Paint Technology and Tests

by Henry A. Gardner

CHAPTER XII

NORTH DAKOTA PAINT TESTS

An inspection of the original test fence, erected and painted by the North Dakota Agricultural College, on the grounds of the agricultural Experiment Station at Fargo, was made by the inspection committee[25] representing the Paint Manufacturers’ Association of the United States, on the 19th and 20th of November, 1909. The fence was erected in 1906 and painted with commercial paints, procured in the open market. The east side of the fence was built of soft pine and cedar weather-boarding, such as is almost universally used on houses in that locality, presenting a very good surface for test purposes, while the west side was built largely of flat trimmed boards of hard pitch pine which, unfortunately, contained knots, pitch pockets, and uneven surfaces, causing to a greater or lesser extent cracking, scaling, and bad general results on all paints applied thereto.

[25] Henry A. Gardner, Director Scientific Section, Educational Bureau, Paint Manufacturers’ Association of U. S.; George Butler, Master Painter; Charles Macnichol, Master Painter.

The fences built in 1907 and 1908 at the suggestion of the Paint Manufacturers’ Association, were inspected on the 20th, 21st, and 22nd of November, 1909, and the detailed results of the inspection of all these fences follow in this report. The same general conclusions as to the woods represented in the 1906 fence also apply to the 1907 and 1908 fences, and because of the general bad quality of wood used on the western exposure of all fences, the detailed reports were made only from an examination of the eastern side of the fences, both on cedar and soft pine.

The following general summary of the inspection and its results applies to all the test fences on the grounds of the college and is the unanimous conclusion drawn by the inspectors from this work:

“Non-absorbent woods, difficult to penetrate, such as those on the west side of the fences, would undoubtedly have given much better results had they been painted with paints properly reduced to suit the nature of the wood. This treatment seems to have been overlooked in the North Dakota tests, and the painting of the hard pine boards was done with the same consistency of mixtures and the same reductions as upon soft pine. Scaling of course resulted. One of the chief purposes of the fences, however, was to study the different types of wood, and compliance with this desire resulted in the bad conditions herein noted. It has been shown in many other field tests that adherence of paints to hard wood surfaces can be obtained only by causing the priming coat to become amalgamated with the woody fibre, by the use of a large percentage of volatile diluent turpentine, benzole, asphaltum spirits, etc., to secure penetration. If such treatment is omitted, failure soon results, as was evidenced by the uniformly bad conditions presented by the paints on the hard pine panels.

North Dakota Test Fences

Typical Sample of Hard Pine Trim Board Showing Knot and Sappy Grain

Test No. 13—1906 Fence
Complete Disintegration and Failure of Cheap Paint

Pine Weatherboarding Showing Knots and Grain

Condition of Lumber Affecting Paint, West Side 1906 Fence

Hail-stone Abrasions on House Repainting Tests

Hail-stone Effect, West Side of 1907 Test Fence

“During July, 1908, a violent hailstorm occurred in Fargo, and left its impression on nearly every wooden structure; in many cases deep dents being made into the wood. The west side of the test fences, which received the most injury from this storm, was covered with these dents over almost its entire surface, causing cracks in the form of concentric rings to appear on the abraded paint coatings. The bad condition of the wood, improper method of applying priming coat, combined with the hailstorm effect on the painted surfaces on the west side of the fences, were undoubtedly responsible for the universal failure of the paints thereon, and, for these reasons, the west side was eliminated from the detailed inspection, only general observations of these tests being made. These general observations, however, showed that paints Nos. 6 and 8 on the 1906 fence, and paints Nos. 8, 10, and 13 on the 1907 fence, proved the most satisfactory on the western exposure.[26]

[26] These formulas were the same as those respectively numbered on the Atlantic City and Pittsburg fences.

Peculiar Crystallization Effect on Section 41. New Special Fence Paint Applied During Cold Weather

“Ochre was tried out as a priming coat on several formulas, but it was found to be most unsatisfactory, affecting the subsequent coats of paint and causing early failure, as evidenced by broad checking, discoloration, and general bad condition. These conditions also apply to those panels on the 1908 fence coated with shellac as a primer.

“The colored formulas in every case showed a great superiority over the same paints in white untinted, and demonstrated that a percentage of color has a wonderful influence on the preservation of the paint coating, reducing chalking, checking, and general disintegration. This condition is probably due to the reinforcing value of the color pigments used.

“It is safe to state that the combination formulas tinted yellow were of better appearance than the corroded white leads tinted yellow, the latter appearing quite dark in many cases.

“The wearing of the paints made solely from white lead and zinc oxide seemed to indicate that a percentage of a third pigment, of an inert nature, would have been beneficial.

“The high-type mixtures of pigments containing lead and zinc, with moderate percentages of inert pigments, on good wood, were in most excellent general condition; in fact, much superior to the single pigment paints. Their surface exhibited only minor checking and moderate chalking with good maintenance of color, and presenting surfaces well adapted to repainting.

“The sublimed white lead was in fair condition, with very little checking, and offering a fair repainting surface. The corroded white lead was somewhat whiter than the sublimed white lead, but a careful observation of the surface of the corroded lead revealed deep checking.

“It was clearly demonstrated, however, that in climates of the North Dakota type, white lead alone is not entirely satisfactory. The addition of zinc oxide to white lead forms paint that has proved much superior to the white lead alone.

“It was conclusively demonstrated that mixtures of white lead and zinc oxide, properly blended with moderate percentages of reinforcing pigments, such as asbestine, barytes, silica and calcium carbonate, are most satisfactory from every standpoint, and are superior to mixtures of prime white pigments not reinforced with inert pigments.

“The white leads painted out on the 1908 fence exhibited different degrees of checking, the mild-process lead and sublimed white lead which presented the best surfaces, being free from checking, while the old-process leads seemed to show very deep and marked checking, even after one year’s wear.

Corroded White Lead	Sublimed White Lead
Condition of Two White Leads on Two Grades of Wood

Photomicrographic Apparatus and Method of Use

CONDENSED REPORT OF INSPECTION OF “1906” TEST FENCE

Fargo, N. D., Nov. 19-23, 1909
No gloss shown by any of the paints. Formulas in white on white pine only included here, on east side of fence

Test No.	FORMULAS																														REPORT OF CONDITION
	Pigment																		Vehicle
	Cor- roded White Lead		Sub- limed White Lead		Zinc Oxide		Cal- cium Car- bonate		Silica and Sili- cates		Barium Sul- phate		Magne- sium Sili- cate		Clay and Silica		Bary- tes and Sili- cate		Lin- seed Oil		Turp. and Drier		Japan Drier		Water		Ben- zine Drier		Vola- tile Oil		Chalking	checking	hiding power	color	condition for repainting
	%		%		%		%		%		%		%		%		%		%		%		%		%		%		%
1	100		—		—		—		—		—		—		—		—		—		—		—		—		—		—		Very bad	Extremely deep	Good	Good	Only fair
2	—		100		—		—		—		—		—		—		—		—		—		—		—		—		—		Bad	Very slight	Good	Light yellowish tint	Fair
3	50		—		50		—		—		—		—		—		—		90		10		—		—		—		—		Medium	Fine matt—deep in places	Good	Fair	Fair to good
4	—		60		40		—		—		—		—		—		—		90		—		10		—		—		—		Medium	Surface checking, very slight	Good	Good	Fair
5	28	.7	—		71	.3	—		—		—		—		—		—		93		7		—		—		—		—		Slight	Quite deep	Medium	Good	Poor. Coating wrin- kled and hard
6	40	.2	—		50	.3	4	.1	5	.4	—		—		—		—		90	.7	9	.3	—		—		—		—		Medium	Slight surface checking	Good	Good	Good
7	21	.9	21	.9	45	.8	10	.4	—		—		—		—		—		89	.6	9	.7	—		0	.7	—		—		Medium	Surface checking with slight cracking	Fair	Good	Slight shelling from wood
8	44	.1	—		46	.0	4	.6	—		—		5	.3	—		—		86	.0	12	.6	—		1	.4	—		—		Medium	Very slight	Good	Good	Good
9	In gray only No report.
10	13	.9	—		34	.9	26	.8	—		—		—		—		24	.4	72	.2	—		—		24	.0	3	.8	—		Slight	Very bad	Bad condition throughout.
11	55	.0	—		15	.2	—		—		—		—		—		29	.8	Test not finished
12	—		5	.1	25	.0	—		—		—		—		—		69	.9	—		—		—		—		—		—		Medium	Medium	Deficient	Good	Shelling from wood
13	—		—		31	.3	45	.4	—		22	.8	—		0	.5	—		57	.2	—		—		16	.1	26	.7	—		Worst looking surface in North Dakota tests.
14	34	.8	5	.4	59	.2	—		—		—		—		—		—		86	.0	13	.7	—		0	.3	—		—		Medium	Slight surface checking and peeling	Fair	Good	Good
15	—		—		64		—		—		36		—		—		—		98		—		—		—		—		2		Slight	Lateral cracking quite deep	Good	Good	Hard film

CONDENSED REPORT OF INSPECTION OF “1907” TEST FENCE

Fargo, North Dakota, Nov. 19-23, 1909

Test No.	FORMULAS																																						REPORT OF CONDITION
	pigment																						vehicle
	Cor- roded White Lead		Sub- limed White Lead		Zinc Oxide		Cal- cium Car- bonate		Alu- minum and Magne- sium Sili cate		Barytes		Silica		Inert		Magne- sium Sili- cate		Cal- cium Sul- phate		Zinc Lead		Lin- seed Oil		Tur- pen- tine Drier		Tur- pen- tine and Japan		Water		Turpen- tine and Ben- zine Japan Drier		Drier		Vola- tile Oil		Ben- zine		Chalking	Checking	Hiding Power	Color	Condition for Repainting
1	30		—		70		—		—		—		—		—		—		—		—		93		7		—		—		—		—		—		—		Medium	Considerable with lateral cracking	Fair	Fair	Poor surface; too hard
2	50		—		50		—		—		—		—		—		—		—		—		86		—		10		4		—		—		—		—		Medium	Considerable with lateral cracking	Good	Fair	Rather poor
3	20		20		50		10		—		—		—		—		—		—		—		90		—		—		—		10		—		—		—		Bad	Medium—scaling some	Good	Good	Fair
4	48	.5	—		48	.5	3		—		—		—		—		—		—		—		83		—		—		—		17		—		—		—		Medium	Considerable with lateral cracking	Good	Good	Medium
5	22		—		50		2		26		—		—		—		—		—		—		90		—		—		—		—		10		—		—		Slight	Slight	Good	Good	Good
6	—		—		64		—		—		36		—		—		—		—		—		98		—		—		—		—		—		2		—		Medium	Considerable	Medium	Medium	Fair
7	37		—		63		—		—		—		—		—		—		—		—		85		13		—		2		—		—		—		—		Considerable	Present; long cracks	Fair	Fair	Poor
8	38		—		48		—		—		—		14		—		—		—		—		91		9		—		—		—		—		—		—		Slight	Surface checking	Good	Good	Fair
9	—		—		73		2		—		—		25		—		—		—		—		66		—		—		12		22		—		—		—		Not evident	Considerable with lateral cracking	Medium	Good	Medium
10	44		—		46		5		—		—		—		—		—		—		—		86	.0	12	.5	—		1	.5	—		—		—		—		Medium	Very slight	Good	Good	Good
11	50		—		50		—		—		—		—		—		5		—		—		78		22		—		—		—		—		—		—		Slight	Lateral cracking	Fair	Fair	Fair
12	60		—		34		—		—		—		—		6		—		—		—		91		7		—		2		—		—		—		—		Considerable	Present with slight cracking and scaling	Fair	Fair	Not very good
13	—		60		27		3		—		—		—		—		10		—		—		90		—		—		—		—		10		—		—		Medium	Surface checking only	Good	Good	Good
14	25		20		25		5		—		—		—		—		—		25		—		90		—		6		—		—		—		—		4		Considerable	Considerable with lateral cracking	Medium	Fair	Medium; some washing shown
15	—		20		40		10		—		—		—		—		—		—		30		90		—		8		2		—		—		—		—		Medium	Medium	Good	Good	Medium
16	33		—		33		—		—		34		—		—		—		—		—		90		—		10		—		—		—		—		—		Medium	Slight; some shelling	Fair	Good	Medium
17	100		(Type		A)		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		Bad	Alligatoring; deep checking	Good	Fair	Poor
18	100		( „		B)		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		Bad	Alligatoring; deep checking	Fair	Fair	Poor
19	100		( „		C)		—		—		—		—		—		—		—		—		10 gal. oil reduction								—		—		—		—		Bad	Deep	Good	Fair	Poor
20	—		100		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		Considerable	Slight	Good	Fair	Fair
21	—		—		100		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		—		Not evident	Considerable; slight cracking; scaling	Fair	Good	Poor
22	—		—		—		—		—		—		—		—		—		—		100		—		—		—		—		—		—		—		—		Medium	Lateral cracking; split	Good	Good	Fair
23	100		(Type		C)		—		—		—		—		—		—		—		—		51⁄2 gal. oil reduction for priming																Bad	Medium deep	Good	Good	Fair
24	37	.51	7	.84	25	.87	20	.36	—		—		8	.42	(Michigan Seal White Lead)										—		—		—		—		—		—		—		Considerable	Slight; lateral cracking	Fair	Good	Good
25	38	.95	4	.81	33	.58	19	.48	—		—		3	.18	(Railway White Lead)								—		—		—		—		—		—		—		—		Considerable	Some; lateral cracking	Fair	Good	Excellent
200	15	.625	—		—		1	.875	—		—		—		—		1	.250	—		43	.750	32	.250	4	.000	—		1	.250	—		—		—		—		Medium	Bad cracking	Good	Good	Fair

“As before stated, the committee believes that a serious mistake was made on the test fence in painting out the leads and other formulas on the various woods without any special attention to reduction to suit the nature of the wood, thus accounting largely for the difference of the wearing of the paints on the different woods.

“The reduction of the white leads especially was to be criticised in these tests, in many cases too much oil and not sufficient turpentine being present to cause penetration.

“The application of paint to cedar was satisfactory in most all cases, and this wood showed much better results than the other woods upon the fences. The exudation of resinous pitch on the hard pine was extremely serious, in some cases coming through the paint in large streaks, causing bad results.

“It is to be regretted that the house repainting tests which were conducted are of no special value, inasmuch as no information is on file as to the composition of the old paints originally on the houses before the application of the test paints. Imperfections in the old coating, such as excessive chalking, deep checking, scaling, rosin exudations, etc., affected the subsequent coats in such a manner as to prevent any knowledge of where the new and old paint troubles began. The committee, therefore, omitted a detailed inspection of such tests.

“Examination of the three houses which were painted over new wood showed results which correspond with the results obtained from the fence tests. That is, they showed the ultimate value of high type mixtures of several pigments over one pigment alone. These tests seem to indicate that very good results can be secured from most of the paints sold in North Dakota. If the consumer or householder would exercise more care in the selection of wood and preparation of surfaces, with due regard to the proper reduction for various coats, more satisfactory results would be obtained.

“From an examination of certain paints on the 1908 fence containing petroleum spirits, it would appear that this paint thinner is of value, and in the face of conditions such as are presented by the present scarcity of turpentine, the use of petroleum spirits in moderate quantity would be justified.”

NORTH DAKOTA TESTS

1. Formula No. 21, Section 31, on 1907 Fence	2. Section 80, on 1908 Fence
3. Formula No. 6, Section 9, on 1907 Fence	4. Formula No. 2, Section 3, on 1907 Fence
5. Formula No. 1, Section 1, on 1907 Fence	6. Formula No. 14, Section 21, on 1907 Fence
7. Formula No. 13, Panel 19, on 1907 Fence	8. Formula No. 19, Panel 28. Broad, Deep Checking onCorroded White Lead on 1907 Fence
9. Formula No. 24, Panel 36, on 1907 Fence. GoodCondition. Surface Checking Only	10. Formula No. 25, Section 37, on 1907 Fence. GoodCondition. Surface Checking Only
11. Formula No. 8, Panel 12, on 1907 Fence	12. Formula No. 10, Panel 15, on 1907 Fence
13. Panel No. 34, Formula 23, on 1907 Fence. DeepChecking on Corroded White Lead	14. Test No. 13 on 1906 Fence. White SpotsShow Paint Left on Wood. Balance of Paint Split and Disintegratedfrom Surface
15. Test No. 6 on 1906 Fence. Surface Checking Only	16. Test No. 2, 1906 Fence. Sublimed White Lead
17. Cracks in Test No. 15 on 1906 Fence	18. Effect of Cracking on Hard Pine, Causing Splittingof Painting Coating
19. Formula No. 22, Section 23, 1907 Fence. Cracks in Paint Coating, Causedby Cracks in Wood; Coating Otherwise in Good Condition	20. Test No. 8, on 1906 Fence. Surface Checking Only
21. Combination Cracking and Checking on Section 69, on 1908 Fence
22. Cracks in Paint Coating, Caused by Cracking of Hard Pine Wood	23. Section 65 on 1908 Fence. Showing Early Breakdown of Corroded White Lead

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CHAPTER XIII

TENNESSEE PAINT TESTS

Location and Object of Tests. On September 15, 1910, the erection of a wooden test fence was completed on the State Fair Grounds at Nashville, Tenn. Upon this fence were exposed forty-two samples of white paint, the object of the test being to determine whether the combination type of formula is superior to the single pigment type in the southern plateau, of which Nashville is the centre.

Construction of Tests. The construction and outline of these tests differ somewhat from those conducted at Atlantic City and elsewhere by the Scientific Section. The fence frame is 150 feet long, being made of 6-inch bevelled girders supported three feet from the ground by 4-inch posts set six feet apart. Upon this girder were placed a series of forty-two test panels supported at top and bottom with weather strips and braces. The test panels used were 40 inches high, 30 inches wide, and one inch thick, being made of the highest grade white pine, tongued and grooved together, and protected on the edges by weather strips projecting from the surface of the panels. Each panel was painted on both sides with the same paint, thus giving an eastern and western exposure, the fence running north and south. The formulas used in the test vary in their percentage composition, being made up in some cases of single pigments, and again with combinations of the opaque white pigments, with and without certain percentages of the crystalline or inert pigments. The paints were applied under the supervision of prominent master painters and a committee representing the Scientific Section and other technical organizations.

Other field tests have shown that the sap and knots in hard-grained woods, such as yellow pine, cypress, etc., have been the cause of the failure of even the best paints, and that all tests should be conducted upon soft woods, such as white pine and poplar, if definite results are to be obtained. Paints tinted with ochre, chrome yellow, lampblack, iron oxide, etc., have shown on the other field tests which have been conducted at Atlantic City, Pittsburg, and Fargo the value of these pigments in giving to the paints increased wearing properties. On the Southern Test Fence, therefore, all the formulas were ground in white only and placed upon white pine so as to make the test primarily one to determine the value of the various white pigments upon good wood.

Tennessee Test Fences

Oil and Thinner Tests. Upon one series of panels on the fence was placed one of the formulas which had given universal satisfaction on the various test fences in the past, and this formula was made up with various oils other than linseed oil, in order to determine the value of these oils as painting materials. For instance, the vehicle part of the one formula referred to is made up of 50% linseed oil and 50% soya bean oil, and again 50% linseed oil and 50% rosin oil, etc., an effort being made to test out a few of the available semi-drying oils.

The same formula referred to was ground in pure linseed oil and subjected to a series of tests where it has been thinned for application as priming and second coats with a series of wood turpentines obtained from the United States Forest Products Laboratory at Madison, Wis. These turpentines were made from southern pine stumps and sawdust, and they vary greatly in their properties. Some were objectionable in odor, while others were of excellent quality, having an odor almost equal to that of pure gum spirits.

Views of Fence

One product under test on the Southern Test Fence is pine oil, a high boiling point product obtained from the manufacture of wood turpentine from sawdust. This oil has a boiling point of over 210 degrees Centigrade as against the 150 degrees of ordinary gum spirits. It is almost water white and has the same penetrating qualities as the pure gum spirits; when mixed with 50% linseed oil forming a paint oil of extremely light color, that produces a semi-flat paint of great whiteness.

Reductions and Application. Formulas No. 1 to No. 37 were all ground in pure refined linseed oil. They were made in the form of semi-paste and then thinned down with sufficient refined linseed oil so that each would have a relative viscosity. To each formula was then added a sufficient amount of pure lead and manganese linoleate drier to give proper drying qualities. On thinning for the priming coat, one pint of turpentine was added to each gallon of paint. For the second coat, one-half pint turpentine and one-half pint refined linseed oil were added to each gallon. For the third coat work, reduction was made with one pint of refined linseed oil.

In the case of formulas 31 to 37, reductions were the same, except that a series of specially prepared wood turpentines were used in place of the pure gum spirits used in formulas 1 to 31.

Formulas 38 to 41, as will be shown, were ground in equal parts of the oils tested. These formulas, however, were all thinned for application with pure gum spirits of turpentine, and the respective vehicle in which they were ground.

No inspection of the Tennessee Test Fence has yet been made. The formulas tested are as follows:

FORMULAS FOR SOUTHERN TEST FENCE

Vehicle: Bleached Linseed Oil with Lead and Manganese Linoleate Drier.

For- mula No.
1	[27]Corroded white lead	100%
2	[27]Sublimed white lead	100%
3	Zinc oxide XX	100%
4	Zinc lead white	100%
5	Leaded zinc 65%, corroded white lead	35%
6	[27]Corroded white lead	100%
7	[27]Corroded white lead	100%

[27] Corroded White Lead is the Basic Carbonate of Lead. Sublimed White Lead is the Basic Sulphate of Lead.

No. 8
Corroded white lead	85%
Zinc oxide	15%
	100%
No. 9
Corroded white lead	65%
Zinc oxide	35%
	100%
No. 10
Corroded white lead	50%
Zinc oxide	50%
	100%
No. 11
Corroded white lead	40%
Zinc oxide	60%
	100%
No. 12
Corroded white lead	30%
Zinc oxide	70%
	100%
No. 13
Corroded white lead	45%
Zinc oxide	45%
Silica	10%
	100%
No. 14
Corroded white lead	45%
Zinc oxide	45%
Asbestine	10%
	100%
No. 15
Corroded white lead	45%
Zinc oxide	45%
China clay	10%
	100%
No. 16
Corroded white lead	45%
Zinc oxide	45%
Barytes	10%
	100%
No. 17
Corroded white lead	45%
Zinc oxide	40%
Silica	15%
	100%
No. 18
Corroded white lead	45%
Zinc oxide	40%
Asbestine	15%
	100%
No. 19
Corroded white lead	45%
Zinc oxide	40%
Barytes	15%
	100%
No. 20
Sublimed white lead	45%
Zinc oxide	40%
Silica	15%
	100%
No. 21
Sublimed white lead	45%
Zinc oxide	40%
Asbestine	15%
	100%
No. 22
Sublimed white lead	45%
Zinc oxide	40%
Barytes	15%
	100%
No. 23
Zinc oxide	90%
Calcium carbonate	10%
	100%
No. 24
Sublimed white lead	40%
Zinc oxide	45%
Calcium carbonate	15%
	100%
No. 25
Corroded white lead	35%
Zinc oxide	50%
Silica	15%
	100%
No. 26
Corroded white lead	20%
Sublimed white lead	30%
Zinc oxide	40%
Asbestine	10%
	100%
No. 27
Corroded white lead	20%
Sublimed white lead	20%
Zinc oxide	40%
Barytes	10%
Asbestine	10%
	100%
No. 28
Corroded white lead	20%
Sublimed white lead	20%
Zinc oxide	40%
Calcium carbonate	10%
Silica	10%
	100%
No. 29
Sublimed white lead	20%
Corroded white lead	20%
Zinc oxide	30%
Barytes	10%
Asbestine	10%
Calcium carbonate	10%
	100%
No. 30
Corroded white lead	33%
Zinc oxide	33%
Barytes	33%
	99%
No. 31
Corroded white lead	45%
Zinc oxide	45%
Asbestine	5%
Calcium carbonate	5%
	100%

For- mula No.
32.	Same as No. 31 but thinned with wood turpentine No. 1.
33.	Same as No. 31 but thinned with wood turpentine No. 2.
34.	Same as No. 31 but thinned with wood turpentine No. 3.
35.	Same as No. 31 but thinned with wood turpentine No. 4.
36.	Same as No. 31 but thinned with wood turpentine No. 5.
37.	Same as No. 31 but thinned with high-boiling-point petroleum spirits (turpentine substitute).
38.	Same as No. 31 but ground in 50% raw linseed oil, 50% soya bean oil.
39.	Same as No. 31 but ground in 50% raw linseed oil, 50% corn oil.
40.	Same as No. 31 but ground in 50% raw linseed oil, 50% cotton seed oil.
41.	Same as No. 31 but ground in 50% raw linseed oil, 50% rosin oil.
42.	Same as No. 31 but ground in 50% raw linseed oil, 50% pine oil.

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CHAPTER XIV

WASHINGTON PAINT TESTS

The new vehicle test fence at Washington is fully described in the writer’s paper[28] as presented before the American Society for Testing Materials, as follows:

[28] The Practical Testing of Drying and Semi-Drying Paint Oils, by Henry A. Gardner. Paper presented at Fourteenth Annual Meeting, Amer. Soc. for Test. Mater., Atlantic City, N.J., June, 1911.

“The high price attained by linseed oil during the past two years of over a dollar a gallon, together with the unusual scarcity of this valuable oil, has led many investigators into the field of research, with a view of discovering some mixture of other oils to partly replace linseed oil. Many valuable contributions to oil technology have resulted, but the makers and users of paints have wisely demanded specific and authoritative information as to the practical value of proposed mixtures before adopting them. The Institute of Industrial Research, at the request of the Paint Manufacturers’ Association of the United States, has recently started a series of practical paint vehicle tests designed to decide the question at issue.

“Forty-eight white-pine panels have been placed upon a test frame on the grounds of the new laboratory building of the Institute, at Washington, D. C. They are painted with a standard white pigment formula reduced with a different oil formula for every panel. White-pine panels were selected for the test on account of the good painting surface which this type of lumber presents; the grade selected was free from knots or pitch pockets—defects which often ruin a paint test. Each panel was constructed of four tongued-and-grooved planed boards, 22 inches long, 1 inch thick, and 9 inches wide. The boards were leaded together and capped at the sides with weather strips, making the finished panels about 2 feet wide and 3 feet high. The fence upon which the panels were placed was constructed of 4-inch squared yellow pine with open framework, allowing the panels a resting place upon which they were finally secured with sherardized screws.

“Before erecting the panels, they were carefully painted in a paint laboratory especially fitted out for the tests. The work was done during the months of April and May, the temperature averaging from 60 degrees to 90 degrees Fahrenheit. This precaution was taken in order that the paint in each case might become thoroughly dry and hard before exposure, so that there would be no accumulation of dust or effect from exposure during the drying period. The actual painting of each panel was done personally by Mr. Charles Macnichol, master painter, of Washington, D. C., who has had a wide experience in the practical application and testing of paints.

View of Panels on Washington Test Fence

“The viscous nature of several of the oils tested precluded the possibility of grinding each oil formula with the white pigment base selected; great heating of the paint mills and a paste of insufficient fineness was the result of an early attempt at this method. It was decided, therefore, to grind the standard pigment formula to a thick paste in the minimum amount of raw linseed oil. Subsequently a weighed amount of the white pigment base was thinned with the oil formula to be tested, to a standard viscosity, judged by the experienced master painter in charge of the practical application of the formulas as sufficiently heavy for third-coat work. When making the reductions with oil mixtures, an allowance was made for the amount of linseed oil already contained in the ground white pigment base.

“During the application of the first coat an equal amount of turpentine was added to each formula, in the proportion of one-half pint to a gallon of paint; in the application of the second coat there was added to each formula a like amount of an equal mixture of turpentine and the oil formula under test. The third coat was applied without the addition of thinners of any kind.

“It is well known that the time of drying and the condition of the dried film of any oil or mixture of drying or semi-drying oils will vary widely. It is for the purpose of causing oils to set up to a hard film in a short time that metallic driers in the form of salts of manganese and lead, soluble in oil, are added to a paint. Some oils require a large amount of drier, while others require only a very small amount. Those which require a large amount are apt, upon exposure, to be burned up by the drier, resulting in the formation of a powdered and disintegrated film. To add various types of drier or even differing amounts of a drier to the oils under test, seemed very unfair from every standpoint, and it was therefore decided to eliminate the drier question entirely, so as not to vitiate the results by bringing in a factor of this nature. The plan of omitting driers proved successful in the Atlantic City steel-panel paint tests, erected three years ago by the writer under the supervision of Committee A-5 of this Society.

“The systematic methods which are necessary when making paint tests were carefully followed. A standard weighed amount of white pigment paste was placed in a clean paint cup and thinned to the proper consistency with a weighed amount of the oil under test. Proper reductions were made, as before stated. Weighings of the paint, cup, and brush were made before and after application to the panel, in order to determine the quantity of paint used and the spreading power. A period of fifteen days was allowed between the application of successive coats, in order to give each formula sufficient time to dry thoroughly. Although several of the formulas remained tacky for over a week, all dried thoroughly in the time allotted. (Oils which when used alone have slow drying properties, have been found to yield good firm films when used with drying pigments such as lead and zinc.) The backs and edges of each panel were painted with two coats of the paint used on the face of the panel, so as to prevent the admission of moisture. After erection, the panels were numbered with aluminum figures pressed into the surface. Frequent inspections will be made, and at the proper time reports will be issued giving the results of the tests.

“During the painting of the panels considerable interesting data were collected, of which the following is a brief résumé:

“The hiding power of a paint is one of its most important requisites. It was found in the tests that some oils had the effect of lessening, while others had the effect of increasing the hiding power of the standard pigment formula. This may be due in part to the varying refractive indices of the oils used, as well as to the difference in the quantity of oil required in each test. Some oils were very viscous, while others were very light.

“The stiff working of heavy-bodied, blown, or heat-oxidized oils, produced films which in some cases gave a very glossy surface, even on the priming coat. Some of these resembled varnished work when finished. It will be of importance to watch these tests carefully for any signs of early breakdown, which might come from too thick a film. The treated Chinese wood oil paints worked rather stiff but produced very smooth films. The rosin oil paints became slightly lumpy on standing, but worked out to a smooth finish somewhat yellowish in color. The marine animal oils, especially the menhaden oil mixtures, dried to a film slightly flatter than straight linseed oil. Any odor which was present in the paints made from the animal oils seemed to disappear a few hours after application. The cotton seed and corn oil mixtures made the slowest drying paints, but at the end of the second week of the drying period they set up rapidly to firm films. Soya bean and perilla oils behaved like straight linseed oil, the former being a little slower and the latter slightly more rapid in drying properties. The perilla oil was made from one of the first importations into this country, and was dark in appearance. It made, however, a very easy-working and hard-drying paint.

“The oils used in the tests were obtained from reliable sources. After they were received, they were carefully analyzed. The results of the analyses appear in [Table 1].

Table 1. Analyses of Oils Used in the Vehicle Tests

	Specific Gravity		Saponifi- cation Number		Iodine Number		Acid Number
Raw linseed oil	0.93	1	188		186		2.0
Boiled linseed oil (linoleate type)	0.94	1	187		172		2.7
Boiled linseed oil (resinate type)	0.93	0	186		176		2.2
Blown linseed oil	0.96	8	189		133		2.8
Lithographic linseed oil	0.97	0	199		102		2.7
Soya bean oil	0.92	4	189		129		2.3
Menhaden oil	0.93	2	187		158		3.9
Perilla oil	0.94		188		180		2.0
Chinese wood oil (raw)	0.94	4	183		166		3.8
Chinese wood oil (treated)[29]	0.89	8[29]	128	[29]	104	[29]	6.8	[29]
Corn oil	0.92	5	191		118		9.5
Cottonseed oil	0.92	1	193		105		3.6
Rosin oil	0.96	6	27		41		16.7
Whale oil	0.92	4	191		148		—
Neutral petroleum oil[30]	0.91	6	6		12		—

[29] Low constants due to presence of over 40% of volatile matter, largely petroleum spirits.

[30] This oil contained over 20% of petroleum spirits.

“The pigment formula selected for the tests had the following composition:

	Basic carbonate-white lead	20%
	Zinc oxide	35%
	Magnesium silicate	10%
	Barytes	5%
100 lbs. of pigment base ground to a stiff paste in 16 lbs. of linseed oil.

“While this pigment formula was not selected as being superior to certain other formulas, it is of a type that has given very fair service in paint tests throughout the country, and will no doubt serve admirably for the purpose designed in these tests.

“The vehicle formulas in the finished paints are as follows:

	No. 1
	Raw linseed oil	100%
	No. 2[31]
	Soya bean oil	100%
	No. 3[32]
	Menhaden oil	100%
	No. 4
	Raw linseed oil	25%
	Boiled linseed oil (resinate)	75%
	No. 5
	Raw linseed oil	25%
	Boiled linseed oil (linoleate)	75%
	No. 6
	Raw linseed oil	50%
	Boiled linseed oil (resinate)	50%
	No. 7
	Raw linseed oil	50%
	Boiled linseed oil (linoleate)	50%
	No. 8
	Raw linseed oil	50%
	Blown linseed oil	50%
	No. 9
	Raw linseed oil	50%
	Litho. linseed oil	50%
	No. 10
	Raw linseed oil	50%
	Soya bean oil	50%
	No. 11
	Raw linseed oil	50%
	Menhaden oil	50%
	No. 12
	Raw linseed oil	50%
	Perilla oil	50%
	No. 13
	Raw linseed oil	50%
	Treated wood oil	50%
	No. 14
	Raw linseed oil	50%
	Corn oil	50%
	No. 15
	Raw linseed oil	50%
	Cottonseed oil	50%
	No. 16
	Raw linseed oil	50%
	Rosin oil	50%
	No. 17
	Raw linseed oil	50%
	Whale oil	50%
	No. 18
	Raw linseed oil	75%
	Soya bean oil	25%
	No. 19
	Raw linseed oil	75%
	Menhaden oil	25%
	No. 20
	Raw linseed oil	75%
	Perilla oil	25%
	No. 21
	Raw linseed oil	75%
	Treated wood oil	25%
	No. 22
	Raw linseed oil	75%
	Corn oil	25%
	No. 23
	Raw linseed oil	75%
	Cottonseed oil	25%
	No. 24
	Raw linseed oil	75%
	Rosin oil	25%
	No. 25
	Raw linseed oil	50%
	Soya bean oil	25%
	Menhaden oil	25%
	No. 26
	Raw linseed oil	50%
	Soya bean oil	25%
	Treated wood oil	25%
	No. 27
	Blown linseed oil	50%
	Soya bean oil	50%
	No. 28
	Raw linseed oil	25%
	Soya bean oil	25%
	Menhaden oil	25%
	Treated wood oil	25%
	No. 29
	Raw linseed oil	25%
	Soya bean oil	25%
	Menhaden oil	25%
	Corn oil	25%
	No. 30
	Raw linseed oil	25%
	Soya bean oil	25%
	Menhaden oil	25%
	Cottonseed oil	25%
	No. 31
	Raw linseed oil	25%
	Soya bean oil	25%
	Menhaden oil	25%
	Rosin oil	25%
	No. 32
	Raw linseed oil	25%
	Soya bean oil	25%
	Treated wood oil	25%
	Rosin oil	25%
	No. 33
	Raw linseed oil	20%
	Soya bean oil	20%
	Treated wood oil	20%
	Menhaden oil	20%
	Cottonseed oil	20%
	No. 34
	Raw linseed oil	20%
	Soya bean oil	20%
	Treated wood oil	20%
	Menhaden oil	20%
	Rosin oil	20%
	No. 35
	Raw linseed oil	40%
	Soya bean oil	20%
	Corn oil	20%
	Cottonseed oil	20%
	No. 36
	Whale oil	33%
	Treated wood oil	33%
	Raw linseed oil	33%
	No. 37
	Raw linseed oil	25%
	L. O.[33]	75%
	No. 38
	Raw linseed oil	50%
	Raw Chinese wood oil	50%
	No. 39
	Raw linseed oil	75%
	Reducing oil[34]	25%
	No. 40
	Raw linseed oil	50%
	Soya bean oil	35%
	Neutral petroleum oil	15%
	No. 41
	Raw linseed oil	50%
	Soya bean oil	25%
	Neutral petroleum oil	15%
	Tungate drier	10%
	No. 42
	Linseed oil	25%
	Soya bean oil	37%
	Neutral petroleum oil	23%
	Tungate drier	15%
	No. 43
	Raw linseed oil	25%
	Soya bean oil	37%
	Whale oil	19%
	Tungate drier	19%
	No. 44
Special test on white base of the following composition, in pure linseed oil:
	Asbestine	10%
	Corroded white lead	20%
	Sublimed white lead	30%
	Zinc oxide	40%
Upper board of panel reduced with straight turpentine on priming coat.
Second board of panel reduced with wood turpentine on priming coat.
Third board of panel reduced with pine oil on priming coat.
Bottom board of panel reduced with petroleum spirits on priming coat.
	No. 45
	Same pigment formula as No. 44, reduced with:
	Pine oil	50%
	Linseed oil	50%
	No. 46
Special test of white base of the following composition, in pure linseed oil:
	Corroded white lead	20%
	Sublimed white lead	30%
	Zinc oxide	35%
	Asbestine	15%
	No. 47
	Cypress panel unpainted.
	No. 48
Cypress panel painted with formula No. 1, thinned with benzol on thepriming coat.

[31] Dry pigment formula in soya bean oil.

[32] Dry pigment formula in menhaden oil.

[33] Mixture of boiled tung and soya bean oil, thinned with petroleum and turpentine.

[34]

25%	raw linseed oil.
73%	petroleum oil.
2%	drier—lead and manganese linoleate.”

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CHAPTER XV

CEMENT AND CONCRETE PAINT TESTS

Damp-proofing and Waterproofing. The decoration and preservation of cement and concrete is a subject which is being given the careful consideration of many technologists on account of the wide usage of cement for structural purposes, and the necessity of properly guarding it against the destructive effects of moisture.

To obtain with various paints decorative effects, and, at the same time, provide a high degree of damp-proofing, is a process quite distinct from that of water-proofing cement and concrete superstructures. The use, in small percentage, of stearic acid solutions, aluminum stearate, marine animal soaps, and other lime-reacting materials, as a component of concrete while it is being mixed, has been in practice for some time, the resulting mixture being used largely upon base-work subjected to water under high pressure. Although some of the materials used for such purposes actually do give to the concrete a high power of water resistance, the degree of waterproofing to be obtained through the use of many such compounds varies to a wide extent, often interfering with the lime-silica reactions, and ultimately affecting the strength of the finished concrete.

Decorative and Preservative Coatings. The necessity of obtaining suitable paint coatings for cement and concrete surfaces suggested to the writer a series of tests on paints designed to prevent the destructive action of the lime which, by seepage and other physical action, is brought to the surface, causing saponification of some oil coatings, as well as destruction of color. The tests referred to were carried out during 1908, and although great advances have been made since that time in the preparation of concrete paints, the tests have, nevertheless, afforded information of a valuable nature as indicating the proper methods to follow in the painting of cement, as well as suitable materials to use in the manufacture of cement paints. The tests, moreover, show the comparative durability of a number of paints typical of those prominent in the market at the time the tests were started.

View of Concrete Paint Test Panels

Acid Reacting Compounds. A series of acid reacting washes were included in the tests, having been designed as prime coaters for use previous to the application of oil paints. The application of many of these washes has the effect of neutralizing the lime within cement and concrete surfaces, and often precipitate insoluble lime compounds which aid in filling up the outer voids, thus presenting a surface more suitable to receive oil coatings. To the writer who has since made a careful study of the painting of concrete, it would seem advisable for painters to avoid, when possible, the use of these lime neutralizing washes, as some of them have more or less disintegrating and weakening influences upon concrete. Recent laboratory experiments, however, have indicated that zinc sulphate, an acid reacting material used for many years as a wash for concrete surfaces by Macnichol, actually has a strengthening effect upon cement and concrete surfaces. The more successful coatings of to-day, however, are those which may be placed directly upon the cement and concrete surfaces without the aid of such washes. Several fairly successful paints of this type have recently appeared in the market; some of them being made of acid rosins compounded with vegetable oils. Probably one of the first mixtures of this sort was the so-called suction varnish which the master painter has for years used as a prime coating on plastered walls previous to painting. These suction varnishes generally contain a high percentage of rosin, a material having an exceptionally high acid value and thus lending itself successfully to the neutralization of free lime. It has been claimed, however, by certain practical painters that the lime-rosin compounds formed when such paints are applied to the exterior of buildings, are of a brittle nature and subject to early failure. If this is true, it would seem advisable to use in a concrete paint an oil of a relatively unsaponifiable nature, which would withstand successfully the action of the lime, and, at the same time, prevent disruption of the coating and failure of the color used in the paint.

Outline of Tests. The tests referred to as carried out by the writer were made on a brick wall forty feet long, surface-coated with a four-inch coating of Portland cement mortar made of one part of Portland cement and three parts of sharp, clean sand. After the cement had hardened for three days, the solutions under test were applied.

In many of the tests outlined above, one-coat, as well as two-coat work, was used on different sections of the test surfaces. It was shown that the two-coat work gave far better results than with the one-coat work, and the writer would recommend for the painting of concrete at least two-coat work. Whenever paints containing Prussian blue or chrome green are applied to concrete surfaces, immediate whitening in the case of the blue, and yellowing in the case of the green, will take place, if any degree of action has been exerted by the lime within the concrete. For this reason, green is an especially delicate color to test and should be utilized for this purpose.

The materials used, and the results shown at an inspection made after two years’ exposure, are given herewith.

Test No. 1. Concrete primed with a 25% solution of zinc sulphate crystals dissolved in water. A wide brush was used for the application, and the spreading rate was approximately 200 square feet per gallon. Second and third coated on the second day with No. 119 blue paint of the following composition:

No. 119 Blue Paint

Sublimed white lead	50%
Zinc oxide	35%
Silica and barytes	12%
Prussian blue	3%
Ground in linseed oil, turpentine and drier.

This panel, after three years’ exposure, is in good condition. Slight checking observed.

Test No. 2. Concrete primed with a 20% solution of (alum) (aluminum sulphate). Second and third coated with No. 119 blue.

In similar condition to Test No. 1.

Test No. 3. Concrete primed with zinc sulphate followed by two coats of para red.

Para Red Formula

Blanc fixe	60%
Whiting	25%
Zinc oxide	3%
Paranitraniline lake	12%
Ground in linseed oil, turpentine and drier.

Panel in fair condition with exception of slight crazing. Characteristic dullness of color after exposure shown. Bright red color restored upon washing.

Test No. 4. Concrete primed with an 8% solution of stearic acid and rosin dissolved in benzine. Second and third coated with No. 119 blue.

This panel is not in as good condition as Tests Nos. 1 and 2, and would indicate the inferiority of the priming liquid used. Color failing in spots and checking observed.

Test No. 5. Concrete primed with mixture used in Test No. 4, and then given two coats of para red.

Test is in about the same condition as No. 4.

Test No. 6. Concrete primed with a 10% mixture of acid calcium phosphate, followed with two coats of No. 119 blue.

The acid phosphate solution evidently had a neutralizing effect upon the lime in the concrete, as the paint is in fair condition.

Test No. 7. Concrete primed with one coat of a soap emulsion of the following composition, then painted with two coats of No. 119 blue.

Water	85%
Linseed oil	12%
Alkali	3%

Very poor results obtained. Destruction of color and peeling resulted.

Test No. 8. Concrete primed with one coat of white paint of the following composition:

Primer

Zinc oxide	25%
Silica	35%
Corroded white lead	20%
Gypsum	15%
Whiting, etc.	5%
Ground in a vehicle of linseed oil and containing 35% of volatile hydrocarbonspirits and drier.

This coat was followed by one of the following composition, tinted blue:

Zinc oxide	60%
Gypsum	20%
Silica	20%
Ground in linseed oil with 12% of turpentine and drier.

Fair results shown during first year, but a breakdown occurred during the second year, and cracking and scaling resulted.

Test No. 9. This test was a duplicate of No. 8 with the addition of 5% of zinc sulphate solution emulsified into the primer.

Slightly superior to Test No. 8.

Test No. 10. Primed with a white paste paint thinned with turpentine. Second coated with same paint tinted blue.

Formula of Paste

Zinc oxide	40%
Whiting	30%
Silica	20%
Alumina and gypsum	10%
Ground in 16% of linseed oil vehicle.

Scaling and peeling due to lack of binder and use of saponifiable oil resulted during the first six months’ exposure. Entire destruction of coating at end of two years.

Test No. 11. Primed with a white mixture, and second coated with the same mixture tinted blue.

Formula of Mixture

Whiting	30%
Silica	30%
Zinc oxide	40%
Stirred into a 5% solution of glue in water, until a fairly thick paste wasobtained.

Much chalking was shown, and a bleaching of color. It is evident that this mixture would not serve to keep moisture out.

Test No. 12 A. Primed with a 5% solution of soluble nitrated cotton and paraffin dissolved in equal parts of amyl acetate and benzine. Second coated with No. 119 blue.

Not very good results were obtained, chalking and slight scaling resulting.

Test No. 12 B. Primed with a heavy varnish containing Chinese wood oil and kauri gum. Second coated with No. 119 blue.

Fair results obtained.

Tests Nos. 13, 14, 15, and 16. Primed with a solution made by dissolving 10 parts of sodium oxalate in 100 parts of water. Second and third coated with linseed oil paints in red, brown, blue, and green.

Very good results shown at end of test.

Test No. 20, Special. Primed and second coated with a green paint containing zinc oxide and barytes, ground in an oil having a low saponification value. Very slow drying was shown. Excellent results. No failure of color. Extremely glossy, waterproof surface presented.

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CHAPTER XVI

STRUCTURAL STEEL PAINT TESTS

The Necessity of Protective Coatings. Most painters have in the past considered of minor importance the painting of iron and steel; any paint that would properly hide the surface of the metal being accepted without much question. The demand, however, for structural steel for office buildings, factories, steel cars, railroad equipment, etc., has doubled the output of structural paints, and created a demand for painters having a knowledge of the proper materials to use in the painting of steel, so that its life may be preserved, and its strength maintained. Such knowledge is as important to the painter as a knowledge of how to properly select materials for the painting of wood, and how to temper these materials to suit the various conditions met with.

The Cause of Rust. Everyone is familiar with the appearance of rust, but few actually understand what causes rust. No attempt will be made here to present even an outline of the many theories advanced to explain the phenomenon of the rusting of iron, for the subject is as diverse as it is interesting. A brief résumé, however, will be given of the now generally accepted theory that explains the subject. This theory is called the electrolytic theory. “Auto-electrolysis” is the term used to define the peculiar tendency of iron to be transformed from a metal possessing a hard lustrous surface, high tensile strength, and other useful properties, to a crumbling oxide that falls to the ground and again becomes part of the earth from which it was originally taken by man.

A Side View of Steel Test Fences

This “going back to nature” is more readily accomplished by most of the steel produced to-day than by the old hand-made irons produced many years ago. It seems to be a curious fact that the more quickly a product or an article is fashioned by man, the more quickly it tends to return again to its original oxidized condition. Some manufacturers of steel, however, through an understanding of the causes of rust, have progressed in the manufacture of slow rusting materials, either by the elimination, or by the proper distribution of impurities.

When iron is brought into contact with moisture, currents of electricity flow over the surface of the iron between points that are relatively pure and points that contain impurities. These currents stimulate the natural tendency of the iron to go into solution, and the solution proceeds with vigor at the positive points. The air which the water contains oxidizes the iron which has gone into solution, and precipitates the familiar brown iron rust. Thus water, which acts as an acid, and air, which acts as an oxidizer, have combined together to accomplish the downfall of the metal.

Three Photomicrographs of Corroding Steel

Inhibition and Stimulation of Rust. It is obvious that if means could be devised to stop the solution pressure of iron and make it resistant to the flow of surface electric currents, rust could be prevented. Such methods have been devised, and to better illustrate how they operate, an analogy may be drawn between iron in water and shellac in alcohol.

It is common knowledge that when shellac is placed in alcohol, the shellac will force itself into solution in the alcohol, and form a clear, transparent lacquer. If, however, there should be mixed with the alcohol a quantity of water, it would be found that the shellac could no longer go into solution, and it would remain in its original condition. In the same way, if there be placed in water a small quantity of material, such as soluble chromates, or an alkaline substance like caustic soda or lime, it will be found that iron will no longer have a tendency to go into solution in this treated water, but will stay bright and clean. These materials which prevent the rusting of iron have been called by Cushman, who first advanced these explanations, “rust inhibitors,” or materials which inhibit rusting. The paint maker, realizing the importance of these rust inhibitors, is incorporating them into paints designed for the protection of iron and steel, and the success which paints of this type have met with from a practical standpoint is a justification of what was first called the “electrolytic theory,” which suggested their use.

By placing small, brightly polished steel plates into a mush of paint pigment and water, a determination may be made of the pigment’s effect upon the metal. Some pigments, under such conditions, cause rapid corrosion of the steel plates. Such pigments are stimulators of corrosion, on account of acid impurities which they contain, or because of their effect in stimulating galvanic currents. Many carbonaceous pigments are of this type. Other pigments have the effect of keeping bright the steel plates and preventing rust. Such pigments are of the inhibitive type, and their action is to check or retard the solution pressure of the iron.

The Effects of Moisture. It might occur to the reader that although paint pigments, when mixed up with water and brought into contact with the surface of steel, might show either an inhibitive or stimulative action, that it is by no means certain that the same tendency will be exhibited by pigments when they are properly mixed with linseed oil and laid out as a film upon the surface of steel. In answer to this, it may be well to state that almost no material used by mankind is absolutely dry. Linseed oil, as it is pressed from the seed, comes from the cells, carrying with it a certain small definite percentage of water, and it is quite certain that even the best linseed oil that goes into use is not theoretically dry. Everyone knows, of course, that oil and water do not readily mix and are, in fact, more or less repellent to each other. It is, however, true that, in spite of this, oils can carry quite a percentage of water, without the admixture being apparent to the eye. In addition to this, careful experiments have proved very conclusively that linseed oil films, even after they have oxidized and hardened, have the power to a certain extent of absorbing water from the atmosphere. It is, therefore, safe to say that no linseed oil film in a paint coating is dry all the time. As a matter of fact, there is abundant evidence to show that in rainy weather, and, in fact, when the humidity in the air is high, paint films have absorbed water. As the sun comes out and warms the paint coating, and the humidity content of the atmosphere falls, this water to a large extent evaporates out of the film, only to be taken up again when the weather conditions change. This action may be likened to a breathing of the paint film, that is to say, an indrawing of water under humid conditions, followed by an exhaling of water under dry conditions. With these facts in mind, it must be apparent that pigments laid out in intimate contact with the surface of steel are subjected at all times either more or less to the reactions produced by water contact. Furthermore, as it is a property of water to become saturated with the gases of the atmosphere, such as oxygen, carbonic and sulphurous acids, and other impurities, there is present in a protective paint film at all times the elements necessary to carry on the corrosive process and reactions.

An outline of Cushman’s original research work, upon which has been based the classification of pigments as inhibitors, stimulators, and inerts, is clearly presented in his report[35] as Chairman of Committee U of the American Society for Testing Materials, of which the following is an excerpt:

[35] Page 73, 1910 Proceedings of the American Society for Testing Materials.

Ferroxyl Tests on Painted Steel Surfaces. Upper Row Painted with Stimulative Paints—Lower Row with Inhibitive Paints.

Water Test on Plates Painted—Except in Center Spot. Left Hand Plates Painted with Stimulative Paints, Right Hand Plates Painted with Inhibitive Paints.

View of Steel Plates Painted with Stimulative Paints, after Immersion in Ferroxyl Jelly.

“Three years ago the suggestion was made in a paper presented before the Tenth Annual Meeting of this Society that the various types of substances used as pigments in protective coatings might exert a stimulative or an inhibitive action on the rate and tendency to corrosion of the underlying metal. It was further suggested on a theoretical ground that slightly soluble chromates should exert a protective action when employed as pigments by maintaining the surface of the iron in a passive condition in case water and oxygen penetrated the paint film. In view also of the well-known fact that alkalies inhibit while acids stimulate the corrosion of iron, it was suggested that the action of more or less pure pigments on iron in the presence of water should be thoroughly investigated. Two years ago this Committee invited the co-operation of Committee D-1 (then known as Committee E) in the investigation, and a special sub-committee representing the two main committees was appointed.

“The methods and results of the water-pigment tests have previously been reported and published, and need not be given in detail. Briefly, the method consisted in immersing samples of steel in water suspensions of the various pigments and blowing air through the containers for definite periods of time, the corrosion being measured by the loss in weight sustained by the test pieces. About fifty pigments which are in more or less common use for painting steel were purchased in the open market and distributed among a number of the members of the Committee, who agreed to carry out the work. Each investigator worked independently of the others, except that the same general method was followed; the time of exposure to the corroding action, however, varied in the different experiments. When the results were compared and analyzed by the sub-committee, it was felt that the general agreement of the results obtained by the several investigators was striking and merited further and more systematic work. As a result of these tests the sub-committee tentatively divided the pigments into inhibitors, stimulators, and indeterminates. The word ‘indeterminate’ was selected after considerable discussion, because the words ‘neutral’ or ‘inert’ already possess a special meaning as applied to paint technology. The Committee takes this occasion to emphatically state that in adopting this tentative classification, the words ‘inhibitive’ and ’stimulative’ as used by them up to the present time apply only to the results obtained in the water tests, and the inference that the results obtained have decided which class the pigment will fall into when made into a paint with the usual vehicles and used as a protective coating on iron and steel, is not justified. In order to make this point quite clear, it has been agreed by the Committee to qualify the classification so as to speak of the various materials tested as ‘water stimulative’ or ‘water inhibitive.’”

Apparatus for Testing the Inhibitive Value of Pigments

Importance of Field Tests. Although the laboratory accelerated tests for the determination of the relative value of structural steel paints afford information of some import, there seems to be a general opinion that the best method to follow, if information of a reliable character is to be obtained, is to make actual field exposure tests upon large surfaces. The results of the above described water-pigment tests suggested the erection of a series of steel panels on which to test out the same pigments under practical service conditions. The Paint Manufacturers’ Association of the United States erected and painted the panels, the work being under the constant supervision of the writer, and the inspection of the work under Committee U of the American Society for Testing Materials. A brief résumé of the work[36] is herewith presented.

[36] Page 181, “Corrosion and Preservation of Iron and Steel”—Cushman and Gardner—McGraw-Hill Book Co., New York City.

Pickling and Preparation of Plates. The three types of metal[37] selected for the test were rolled to billets, the middle of which were selected, and worked up into plates 24 inches wide, 36 inches high, and 1⁄8 inch in diameter—approximately 11 gauge. A number of plates of each of the metals selected, in all 450, were pickled in 10% sulphuric acid, kept at 180 to 200 degrees Fahrenheit, in order to remove the mill-scale. The plates were then washed in water, and later in 10% solution of caustic soda. Finally the plates were again washed in water and wiped dry. They were then packed in boxes containing dry lime, in order to prevent superficial corrosion. By this method the plates were secured in perfect condition, the surfaces being smooth and free from scale. Upon these pickled plates paints were applied with a definite spreading rate of 900 square feet per gallon. The unpickled plates, coated with mill-scale, were painted with the same paints, but without adopting any special spreading rate, thus following more closely the ordinary method of painting structural steel. A few extra plates of special Bessemer steel and Swedish charcoal iron were also included in the test, some of which were painted, while others were exposed without any protective coating. Plates of the three types of metal already mentioned were also exposed unpainted, both in the black and pickled condition.

[37] Bessemer Steel, Open Hearth Steel, and Pure Iron.

Front View of Steel Test Fences

Fence Erection and Preparation for Work. The fences which were erected for the holding of the plates were constructed of yellow pine, the posts being set deeply in the ground and properly braced. The framework of the fence was open, with a ledge upon the lateral girders, upon which the plates might rest, and to which the plates were secured by the use of steel buttons. After the framework had been erected, painted, and made ready for the placement of the panels, a small shed was built upon the ground, and the materials for the field test placed therein. The steel plates were unpacked from the boxes in which they were shipped, brushed off, and stacked up ready for painting. Small benches were erected, and the accessories of the work, such as cans, brushes, pots, balances, etc., were placed in position.

Methods Followed in Painting Plates. A frame resting upon the workbench served to hold the plates in a lateral position while being painted, room being allowed beneath the plate for the operator to place his hands in order to lift the plates from the under surface after the painting had been finished.

A pickled plate having been placed upon the framework everything was in readiness for the work. The specific gravity and weight per gallon of the paint to be applied was determined, and the amount, in grams, to be applied to each individual panel was calculated according to the following formula:

Spreading rate		Sq. ft. in plate		Grams paint in gal.
900 sq. ft.	:	6	::	5400	:	x

The reciprocal of x being the number of grams of paint to be applied to the panels.

An enamel cup was then filled with the paint and a brush well stirred within. The cup, paint, and brush were placed upon the balances and accurately weighed in grams. After most of the paint had been applied to the panel, cross-brushing of the panel was continued until the pot with brush and paint exactly counterbalanced the deducted weight. The painted panel was then set in a rack, in a horizontal position to dry.

A period of eight days elapsed between the drying of each coat. The greatest care was taken in the painting of the edges of the plates, and the racks for containing the plates after they were painted were so constructed that the paint would not be abraded while sliding the plates back and forth. The working properties of each paint, and the appearance of the surface of each plate after painting, were carefully noted and included in the report. No reductions were made to any of the paints applied except in three cases, where the viscosity was so great that it was necessary to add a small amount of pure spirits of turpentine. The amount of paint was proportionately increased in such cases, so that the evaporation of the turpentine would leave upon the plate the amount of paint originally intended.

The appearance of the completed series of test panels is shown on [page 221].

Vehicles Used and Reasons for Avoidance of Japan Driers. The pigments used were selected with the view to securing as nearly as possible purity and strength, and as already noted, were out of the same lots used in making the preliminary laboratory tests on inhibitives. They were ground in a vehicle composed of two parts of raw linseed oil and one part of pure boiled oil. Paint is generally caused to dry rapidly by the use of japan or driers. These materials contain a large amount of metallic oxides which might have some effect in either exciting or retarding corrosion. To prevent the introduction of such a factor, these materials were not used in the test. The boiled oil, with its small percentages of metallic oxides, was sufficient, however, to cause the paints to dry in a short time after they were spread.

Testing Effect of Various Prime Coats. Some of the special tests made included a series of plates prime-coated with different inhibitive pigments, and these tests were designed to determine which pigments offer the best results for such work. These plates were all second-coated with the same paint. It is the opinion of the authors that any good excluding paint may be used whether it be inhibitive in action or not, provided the contact coat is inhibitive. If, however, both coats can be designed so as to have the maximum possible value from both these points of view, the best results would, of course, accrue. The only way such data can be obtained is by careful observation of the results of exposure tests.

Combination Formulas Tested. By selecting a series of pigments which in the water tests showed inhibitive tendencies, and properly combining these pigments into a paint, it was thought possible that a more or less inhibitive paint would be produced. If this proved to be the case, it would follow that the selection and introduction into a paint of the stimulative pigments would inevitably produce a paint unfit for use on iron or steel.

Data on Application of Paints. The recorded data on the application of the paint to the panels is voluminous. There is presented herewith, however, the data on two of the paints.

No. 2, Quick Process White Lead:
	Sp. Gr. of pigment				6.78
	Lbs. to gallon oil				20.34
	Sp. Gr. of paint as received				2.47
	Wt. of paint per gallon				20.56
	Grams to panel				62
	Condition of paint				Good
	Working properties				Works easy
	Drying				24 hrs. all coats
	1 coat	Oct.	26	T 60	B 29.94	W. fair
	2 coat	Nov.	3	T 54	B 30.23	W. clear
	3 coat	Nov.	7	T 52	B 29.66	W. cloudy
No. 9, Orange Mineral (American):
	Sp. Gr. of pigment				8.97
	Lbs. to gallon oil				26.91
	Sp. Gr. of paint as received				2.97
	Wt. of paint per gallon				24.74
	Grams to panel				74.7
	Condition of paint				Good
	Working properties				Smooth—no brush marks
	Drying				Good
	1 coat	Oct.	28	T 58	B 30.01	W. cloudy
	2 coat	Nov.	4	T 65	B 29.61	W. cloudy
	3 coat	Nov.	9	T 58	B 29.91	W. clear

Composition of Paints. The [following table] gives data regarding the composition, etc., of paints applied to the steel panels.

Results of Inspection. The results of an inspection of the steel test plates, made by Sub-committee D representing Committee D-1 of the American Society for Testing Materials, is herewith presented:

“On Wednesday, June 28, 1911, the second inspection of the Atlantic City Steel Test Panels, erected in October, 1908, was made by Sub-committee D of Committee D-1, this Committee having agreed to report upon the condition of the painted surfaces, leaving any report on the comparative corrosion of the various types of metal used in the test to Committee A-5 on the corrosion of iron.

Pig- ment No.	Name				Sp. Gr. of Pig- ment		Wt. of Pigment to Gal. of oil Lbs.			Sp. Gr. of Paint Rec’d		Wt. of Paint per Gal. Lbs.		Grams Paint to Panel at 900 Sq. ft. spread- ing rate
1	Dutch process white lead				6	.83	20	.49		2	.45	20	.49	61	.0
2	Quick process white lead				6	.78	20	.34		2	.47	20	.34	62	.0
3	Zinc oxide				5	.56	16	.68		2	.12	16	.68	59	.0
4	Sublimed white lead				6	.45	19	.17		2	.36	19	.17	59	.0
5	Sublimed blue lead				6	.39	19	.17		2	.42	19	.17	61	.0
6	Lithopone				4	.26	12	.78		1	.80	12	.78	45	.3
7	Zinc lead white				4	.42	13	.26		1	.96	13	.26	49	.4
9	American orange mineral				8	.97	26	.91		2	.97	26	.91	74	.7
10	Red lead				8	.70	26	.10		2	.93	26	.10	73	.6
12	Bright red oxide				5	.26	15	.78		2	.05	15	.78	60	.0
14	Venetian red				3	.1	9	.30		1	.52	9	.30	38	.0
15	Prince’s metallic brown				3	.17	9	.51		1	.50	9	.51	37	.7
16	Natural graphite				2	.60	7	.80		1	.37	7	.80	34	.4
17	Acheson graphite				2	.21	6	.63		1	.22	6	.63	30	.8
19	{	Lampblack			1	.82	1	.82	}	1	.60	1	.82	40	.2
		Barytes					8	.92				8	.92
20	Willow charcoal				1	.49	4	.47		1	.08	4	.47	27	.0
21	{	Gas carbon black			1	.85	1	.39	}	1	.67	1	.39	50	.7
		Natural barytes					10	.03				10	.03
24	French yellow ochre				2	.94	8	.82		1	.46	8	.82	37	.0
27	Natural barytes				4	.46	13	.38		1	.83	13	.38	46	.0
28	Precipitated barytes (blanc fixe)				4	.23	12	.69		1	.84	12	.69	46	.0
29	Calcium carbonate (whiting)				5	.48	8	.22		1	.37	8	.22	34	.5
30	Calcium carbonate precipitated				2	.56	7	.68		1	.35	7	.68	34	.0
31	Calcium sulphate (gypsum)				2	.33	6	.99		1	.25	6	.99	31	.4
32	China clay (kaolin)				2	.67	8	.01		1	.34	8	.01	34	.0
33	Asbestine (silicate of magnesium)				2	.75	8	.25		1	.38	8	.25	34	.7
34	American vermilion (chrome scarlet)				6	.83	20	.49				20	.49	64	.5
36	Medium chrome yellow				5	.88	17	.64				17	.64	67	.1
39	Zinc chromate				3	.57	10	.71		1	.57	10	.71	39	.2
40	Zinc and barium chromate				3	.45	10	.35		1	.58	10	.35	40	.0
41	Chrome green (blue tone)				4	.44	13	.32		1	.94	13	.32	49	.0
44	Prussian blue				1	.96	5	.88				5	.88	30	.0
45	Prussian blue				1	.93	5	.79				5	.79	34	.5
48	Ultramarine blue				2	.40	7	.20		1	.29	7	.20	32	.5
49	Zinc and lead chromate				4	.76	14	.28		1	.92	14	.28	48	.3
51	Magnetic black oxide						15	.00		1	.92	15		48	.3
	Composite Paints
111	Brown		⎫	Made from pigments that were inhibitive in the water test			10	.82		1	.30	10	.82	32	.7
222	Black		⎬				10	.86		1	.30	10	.86	32	.8
333	White		⎪				14	.52		1	.74	14	.52	43	.8
444	Green		⎭				12	.77		1	.53	12	.77	38	.6
555	Black		⎫	Made from pigments that were stimulative in the water test			9	.37		1	.125	9	.37	28	.
666	Brown		⎬				11	.74		1	.41	11	.74	35	.5
777	White		⎪				14	.55		1	.75	14	.55	44	.
888	Green		⎭				14	.57		1	.75	14	.57	14	.57

“According to the amount of rust apparent on the painted surfaces of the panels, as well as the degree of checking, chalking, scaling, cracking, peeling, loss of color, and other signs of paint failure shown, ratings were given each panel. The system of rating which took into consideration all the above conditions, was similar to the system used at the first inspection during 1910, when 0 (zero) recorded the worst results and 10 (ten) the best results.

“In [Table No. 1] there is shown the rating accorded by each inspector to each panel, as well as an average for each panel.

Table No. 1.—Second Inspection of Steel Paint Test Panels at Atlantic City, N. J.,
by Sub-committee D of Committee D-1

Panel No.	Pigment			W. H. Walker		P. H. Walker		H. A. Gardner Chair- man		C. Chap- man		Aver- age
1	Dutch process white lead			2		3		3		5		3.7
2	Quick process white lead			4		4		3		6		4.2
3	Zinc oxide (XX)			1		1	½	1		2	½	1.5
4	Sublimed white lead			9		9	½	9		8	½	9.0
5	Sublimed blue lead			9		9	½	9	½	7	½	8.8
6	Lithopone			2		1	½	2		3	½	2.2
7	Zinc lead white			3		4		5		7		4.7
9	Orange mineral			9		9		9		6	½	8.3
10	Red lead			9		9		9		6	½	8.3
12	Bright red oxide			8	½	9		8		7		8.1
14	Venetian red			7		9		7		9		8.0
15	Prince’s metallic brown			5		7	½	6		8		6.3
16	Natural graphite			6		8		4		9	½	6.8
17	Artificial graphite			5		7	½	4		7		5.9
19	Lampblack			5		7	½	5		8		6.3
20	Willow charcoal			9		8	½	9		9		8.8
21	Carbon black			7		8	½	5		8	½	7.2
24	Yellow ochre (French)			5		7		2		8		5.5
27	Barytes (natural)			1		1		1		0		0.7
28	Barytes (precipitated)			2		1	½	2		2		1.8
29	Calcium carbonate (whiting)			0		0		0		0		0.0
30	Calcium carbonate (precipitated)			0		0		0		0		0.0
31	Calcium sulphate (gypsum)			1		1		1		3		1.7
32	China clay (kaolin)			6		6		7		6	½	6.3
33	Asbestine (magnes. silicate)			5		4	½	6		5		5.1
34	American vermilion			10		10		10		10		10.0
36	Lead chromate			7		7	½	8	½	8		7.7
39	Zinc chromate			9		9		10		9	½	9.5
40	Zinc and barium chromate			9		9	½	10		9	½	9.5
41	Chrome green (blue tone)			10		10		10		9	½	9.8
44	Prussian blue, W. S			9		9	½	9	½	9		9.0
45	Prussian blue, W. I			8		9	½	8	½	8	½	8.5
48	Ultramarine blue			0		0		0		0		0.0
49	Zinc and lead chromate			10		9	½	10		9	½	9.7
51	Magnetic black oxide			9		9	½	10		9	½	9.5
111	Brown composite paint			7		9		9		9		8.5
222	Black composite paint			9		9		9		8	½	8.8
3333	White composite paint			4		4		7		3		4.5
444	Green composite paint			5		7		7		8		6.7
555	Black composite paint			9		9		6		9		8.2
666	Brown composite paint			8		8		6		9		7.7
777	White composite paint			7		10		5		7		7.2
888	Green composite paint			7		8		8		9		8.0
2000	1 coat zinc chromate	}		8		8	½	8		8		8.1
	1 coat iron oxide excluder
3000	1 coat lead chromate			7		8		7		7	½	7.3
4000	1 coat red lead	}		7		8	½	8		7	½	7.7
	1 coat iron oxide excluder
100	Straight carbon black paint with turps and drier			5		8	½	4		8	½	6.5
90	Straight lampblack paint with turps and drier			5		7		3		8		5.7
5555	Coal tar paint over red lead			4		8		2		7		5.2
1000	Chrome resinate in oil (1 coat)			1		0		0		2		0.7
1 plate	3 coats boiled linseed oil			1		0		1		4		1.5

“In [Table No. 2] there is shown the rating obtained by those panels which were considered by the committee as meriting from 8 to 10, and having given the best all-round service.

Table No. 2.—Analysis of Averages. Grade of Excellence from
8 to 10

Plate	Pigment	Average
34	American vermilion (basic chromate of lead)	10.0
41	Chrome green	9.8
49	Lead and zinc chromate	9.7
39	Zinc chromate	9.5
40	Zinc and barium chromate	9.5
51	Black oxide of iron	9.5
4	Sublimed white lead	9.0
44	Prussian blue	9.0
5	Sublimed blue lead	8.8
20	Willow charcoal	8.8
222	Composite paint	8.8
45	Prussian blue	8.5
111	Composite formula	8.5
9	Orange mineral	8.3
10	Red lead	8.3
555	Composite paint	8.2
12	Bright red oxide of iron	8.1
2000	1 coat zinc chromate; 1 coat iron oxide	8.1
14	Venetian red	8.0
888	Composite paint	8.0

Comparison of Results. It is of interest to compare with [Table 2 of the above report], [Table 2 of the 1910 report] of Committee U of the American Society for Testing Materials. Both charts show the highly inhibitive pigments to be in the lead.

COMMITTEE U REPORT 1910

Table II.—Analysis of Averages. Grade of
Excellence from 8 to 10

(Only resistance to corrosion was considered, and only
pigments which were common to both tests are included)

No.	Pigment	Average
34	American vermilion (chrome scarlet)	9.8
41	Chrome green (blue tone)	9.7
40	Zinc and barium chromate	9.7
5	Sublimed blue lead	9.6
4	Sublimed white lead	9.5
49	Zinc and lead chromate	9.5
39	Zinc chromate	9.4
12	Bright red oxide	9.3
44	Prussian blue (water stimulative)	9.2
16	Natural graphite	9.1
9	Orange mineral (American)	9.0
36	Medium chrome yellow	9.0
2	White lead (quick process)	8.9
20	Willow charcoal	8.8
45	Prussian blue (water inhibitive)	8.8
1	White lead (Dutch process)	8.7
10	Red lead	8.7
7	Zinc lead white	8.0

The writer has recently made a careful inspection of the panels painted with single pigment paints, and has made the following brief summary of the characteristic appearance of each.

Panel No. 1—Dutch Process White Lead. The excessive chalking which took place began to disappear at the end of a year, being washed away by the rains and carried away by the winds, so that there was left upon the surface but a thin coating of pigment, insufficient to give good protection. Slight corrosion was apparent beneath the film.

Panel No. 2—Quick Process White Lead. In the same condition as Panel No. 1.

Panel No. 3—Zinc Oxide. Panel covered with thin lateral streaks of rust, due to the admittance of moisture in cracks caused by brittleness of film. Result doubtless due to insufficient amount of oil used with pigment. Removal of film shows steel very bright except where cracks have formed.

Panel No. 4—Sublimed White Lead. Although sublimed white lead chalked very heavily, the chalked pigment seemed to be tenacious and adhered to the plate, presenting an excellent surface with absence of rust. Film of good color and quite elastic.

Panel No. 5—Sublimed Blue Lead. In same condition as Panel No. 4, but color has slightly faded.

Panel No. 6—Lithopones. Lithopone was early destroyed, as is usual with this pigment when used alone on exterior surfaces. It became rough and discolored, presenting a very blotchy appearance and disclosed the formation of rust working through the film.

Panel No. 7—Zinc Lead White. In general good condition with the exception of the color, which is slightly dark. Medium chalking was apparent but only very slight corrosion appeared.

Panel No. 9—Orange Mineral. In excellent condition, showing a good firm surface with no checking or corrosion apparent. Shortly after exposure the film became covered with a white coating of carbonate of lead, which indicates action of the red lead with the carbonic acid of the atmosphere. Removal of this white coating with water discloses the brilliant color of the unaffected portion of the red lead.

Panel No. 10—Red Lead. In same condition as Panel No. 9.

Panel No. 12—Bright Red Iron Oxide. In general good condition. Film intact and unfading in color.

Panel No. 14—Venetian Red. Similar to Panel No. 12, but slight corrosion apparent beneath, in localized spots, and film showing slight wart-like formations.

Panel No. 15—Prince’s Metallic Brown. Similar to Panel No. 14.

Panel No. 16—Natural Graphite. Deeply pitted in spots, showing bulbous eruptions, indicating the stimulative nature of this pigment.

Panel No. 17—Artificial Graphite. In same condition as Panel No. 16.

Panel No. 19—Lampblack and Barytes. Although the film seems to be intact, there are apparent abrasions of the surface showing stimulative corrosion effects of a pronounced nature.

Panel No. 21—Carbon Black and Barytes. In same condition as Panel No. 19.

Corrosion Pits on Graphite Panel

Rust on Stripped Graphite Film

Section of Wire Painted with a Stimulative Carbonaceous Paint

Corroded and Pitted Surface of Plate Painted with Stimulative Paint

The longevity of lampblack and carbon black paint films when applied to wood has been attributed to the slow drying nature of these pigments when mixed with oil. It is assumed that they have the property of keeping the oil in a semi-drying condition, which will not disintegrate as early as when the oil is thoroughly dried to linoxyn. If this is true, it would seem advisable to use with hard-drying pigments, a proportion of some oil that is semi-drying in nature or one which will leave a film not too hard. Soya bean oil, wood oil, and fish oil present themselves as candidates for such use. How they will work in practice, however, is a question not yet determined. On the other hand, it is well known that these pigments require enormous quantities of oil in order to grind to a working consistency, and it is possible that the life of such coatings is due rather to the property of these pigments, of taking up large quantities of oil, than to their effect upon the slow drying of oil. Excessive oil carrying, however, should be avoided, as shown by the early failure and pitting of those carbon black and lampblack paints ground with very large quantities of oil, as is the usual practice. When these carbon and lampblack pigments were ground with barytes (which is a heavy pigment and requires only about 9 pounds of oil to 100 pounds of pigment, as against 175 pounds of oil to 100 pounds of lampblack), it was found that the lampblack and carbon black paints were reinforced and made more suitable for actual practice. The stimulative nature of these black pigments, however, asserted itself in both cases, and large pittings and eruptions were evident at the end of a year. Carbon black, lampblack, graphite, or any other good conductor of electricity should never be placed next to the surface of iron. They are good as top-coatings, but not as prime-coaters. Some pigments are stimulators of corrosion, because they contain water-soluble impurities that hasten the rusting, while others, like graphite, hasten it simply because, being good conductors, they stimulate surface electrolysis.

Panel No. 20—Willow Charcoal. In excellent condition throughout. Presence of small quantities of potash may be responsible for the inhibitive nature of this black pigment.

Panel No. 24—Ochre. While the film seems intact, it has a very mottled appearance and examination shows eruptions of rust through the film, in several places.

Panel No. 27—Natural Barytes. Within a year the film became pin-holed, and corrosion was apparent. At the end of three years very little of the pigment was left upon the plate, having chalked and scaled off. Barytes has proved its usefulness as a constituent of a combination type of paint, but it should not be used alone.

Panel No. 28—Blanc Fixe. In the same condition as Panel No. 27, but slightly more chalking and disintegration was shown.

Panel Painted with Blanc Fixe. Right Side Stripped of Paint to Show Corrosion

Scaled Whiting Films

Chemically Active Pigments and Their Effect After Eighteen Months’ Wear

Plate Showing Effect of Chemically Active Pigments on Oil after One Year’s Wear

Panel No. 29—Whiting. Plates coated with calcium carbonate or whiting in oil presented a very fair appearance at the start of the test, but they soon began to chalk and disintegrate. It is well known that whiting, being alkaline, has the property of acting on oil and causing its early disintegration by saponification. As a matter of fact, six months after the whiting plates were exposed, crumbling of the surface appeared, and twelve months was sufficient for the total destruction of the paint. At this time the rusted surface of the plates which had been painted with calcium carbonate, seemed not to rust as fast as those plates which were exposed without paint coatings, and the rust which had formed appeared to be of an even, fine texture. On the lower left-hand corner of these plates had been lettered the figures “29” and “30,” using lampblack in oil. One of the most remarkable things which appears on the fence to-day is the perfect condition of these lampblack letters over their priming coat of calcium carbonate, standing out in clear relief against the rusted metal. This test would suggest, therefore, that if the surface of metal is properly protected with a pigment which is slightly alkaline or inhibitive in nature, and then topped with a good weather-resisting material, such as lampblack, graphite or carbon black, good results would be obtained. Further tests will be made to determine the value of this suggestion.

Panel No. 30—Precipitated Calcium Carbonate. Showed more rapid destruction than Panel No. 29.

Corrosion Adhering to Film Stripped from Panel Painted with Gypsum (Calcium Sulphate)

Panel No. 31—Calcium Sulphate. Under the paint film of gypsum, rust soon appeared, showing that the film was not a good excluder of moisture. Although the film remained intact, rusting progressed throughout the test and considerably darkened the color of the paint.

Panel No. 32—China Clay. This pigment gave excellent service for eighteen months. Afterwards indications of corrosion were shown, and apparent breakdown of the film was indicated.

China Clay	Asbestine	Gypsum

Panel No. 33—Asbestine. In the same condition as Panel No. 32.

Excellent Surface shown by American Vermilion after nearly Four Years’ Exposure

Panel No. 34—American Vermilion. This pigment has given perfect protection to the plates. The film is strong and elastic, and upon removal reveals the bright steel. No chalking, checking, discoloration, or other signs of paint failure are shown. It would appear that the inhibitive characteristics of this pigment are pronounced, and it promises to give efficient service for several years more.

Panel No. 36—Lead Chromate. This panel is in generally fair condition, but slight checking is shown.

Perfect Condition of Plate Painted with Zinc Chromate; One Half Stripped. (Negative cracked)

Panel No. 39—Zinc Chromate. This panel is in condition similar to Panel No. 34, presenting a perfect appearance, with decided maintenance of color, elasticity of film, and freedom from any bad characteristics. It has proved to be one of the highest type rust inhibitive pigments.

Panel No. 40—Zinc-and-Barium-Chromate. Although the color of this pigment is not very pleasing, it has proved itself to be the equal of zinc chromate in its protective value.

Panel No. 41—Chrome Green. In excellent condition. Presents an appearance similar to Panels Nos. 34 and 39. Its surface is perfect and will doubtless give service for many years.

Panel No. 44—Prussian Blue. This panel stands forth as the most wonderful moisture-excluder in the whole test, its surface presenting an appearance similar to a varnished plate, even after three years’ exposure. Action between the pigment and the oil, resulting in the formation of iron linoleate, may account for this property.

Panel No. 45—Prussian Blue. In same condition as Panel No. 44.

Panel No. 48—Ultramarine Blue. Soon after this test was exposed, early vehicle decay and excessive chalking were observed. The admittance of moisture may have caused the formation of acid with the sulphur content of the pigment, which would account for the rapid corrosion which followed. It is of a pronounced stimulative type. The effect of stimulative under-coatings is well shown on some special plates on the fence, which when received were not pickled before painting, but had upon their surfaces the ordinary coating of mill scale. Over this had been stencilled in a triangular form the trade mark of the manufacturer. The stencilling material was made of ultramarine blue. When these plates were painted with some of the special paints, and exposed, the stimulative nature of the ultramarine blue began to assert itself, and within a short time, wherever the stencil marks were located, signs of rust began to appear through the coatings of top paint which had been applied. Corrosion under these stencil marks became so great that the trade mark was plainly outlined in letters of rust. This would seem to be final proof that pigments of a stimulative nature should never be used for the priming of iron and steel.

Panel No. 49—Zinc-Lead Chromate. In excellent condition throughout, with a smooth surface and showing no corrosion. Stands in the same class as Panels Nos. 34 and 39.

Effect of Stimulative Paint. Manufacturer’s Trade Mark Stencilled on Bare Metal in Triangular Form, showing Through Subsequent Paint Coating

Panel No. 51—Black Magnetic Oxide of Iron. In excellent condition.

---

CHAPTER XVII

THE SANITARY VALUE OF WALL PAINTS

Decoration and Sanitation. The proper decoration of the interior of dwellings and public buildings has become of even greater importance than the protection and decoration of exteriors. There is, moreover, an increasing demand for harmonious effects and the production of more sanitary conditions than have prevailed in the past. Up until a few years ago a great variety of wall papers of more or less pleasing appearance were almost exclusively used for the decoration of walls in the interior of buildings, and their application was commonly considered the most effective means of wall decoration. There seems to be no question, however, that the use of wall paper is steadily decreasing, and that the art of interior decoration is undergoing a transition to the almost universal use of paint.

Modern progress demands the maintenance of sanitary conditions for the benefit of the public welfare, and there is no doubt that from the standpoint of sanitation and hygiene, properly painted wall surfaces are far superior to papered walls. There is an abundance of evidence which shows that dust germs may easily be harbored, and thus disease transmitted from wall paper. In the tenement houses, which are common to the larger cities, and to a lesser extent in the dwellings found in smaller communities, where tenants are more or less transient, the continued maintenance of sanitary conditions presents a difficult problem. Infectious and epidemic illnesses generally leave behind bacilli of different types, which may find a culture medium in the fibrous and porous surfaces presented by wall paper, backed up as they invariably must be by starch, casein, or other organic pastes. Occasionally the restrictions of local boards of health provide in such events for proper fumigation, but too often no precautions are taken to destroy the disease germs which are caught in the dust which collects on wall paper. As a rule, both tenant and landlord are oblivious to all conditions which cannot be readily seen or detected. Burning sulphur, one of the most effective means of fumigation, will generally cause bleaching and consequent fading of the delicate colors used in printing the designs upon wall paper. Washing of the paper with antiseptic solutions will destroy its adhesiveness to the plaster and often cause bulging and general destruction.

Heavy Colonies of Bacteria Developing inAgar Jelly Treated with Washings fromWall Paper	Practically no Development of BacterialColonies in Agar Jelly Treated withWashings from Sanitary Wall Paint

Hospital Practice. In hospitals, where it is necessary to maintain sanitary conditions, the walls are invariably painted, and requirements should demand the use of paints which can be washed frequently, so that there will be no possibility of uncleanliness. Inquiry made of a prominent surgeon[38] connected with one of the large metropolitan hospitals substantiated the writer’s findings regarding the greater sanitary value of wall paints, and brought forth the information that in hospitals under construction provision had been made for the finishing of walls so that a hard, non-absorbent, and washable surface might be obtained. The same authority stated that the common practice, in apartments and tenements, of covering the old wall paper over with a layer of new each time a tenant moved in, should be condemned, and that from a hygienic standpoint the use of sanitary wall paints should be advocated in all dwellings as well as public buildings.

[38] Dr. F. F. Gwyer, Cornell Uni. Med. Col., New York City.

If such conditions are maintained in hospitals, where special attention is paid to sanitation, it would appear that similar precautions should be equally as necessary in public buildings and in dwellings—wherever, in fact, people congregate or live.

Sanitary Wall Paints. There have recently appeared in trade a number of wall paints composed of non-poisonous pigments ground in paint vehicles having valuable waterproofing and binding properties, and of a nature to produce the flat or semi-flat finish that has become so popular. Such paints produce a sanitary, waterproof surface, which permits of frequent washing. By their use it is possible to secure a more permanent and a wider range of tints than can be obtained with wall paper, as they are produced in a myriad of shades, tints and solid colors, from which any desired combination may be selected. On the border or on the body of walls decorated with such paints, attractive stencil designs, which bring out in relief the color combinations, may be applied.

For the decoration of chambers and living rooms, delicate French grays, light buffs, cream tints and ivory whites may be used, while in the library and other rooms richer and more solid colors, such as greens, reds, and blues, may be harmoniously combined.

Defects of Wall Paper. It recently occurred to the writer to investigate the conditions which obtain in many apartment houses in the larger cities. Inspection of a number of such places, in which wall paper had been exclusively used on the walls, showed generally bad conditions; bulging of the surfaces, caused by dampness in the walls, which had loosened up the binder, as well as peeling and dropping of the paper from the ceilings, were frequently observed. In many cases a shabby appearance was shown, accompanied by an odor which suggested decomposition of the paste binder used on the paper. The writer was impressed with the fact that such conditions could easily be avoided by the very simple expedient of using properly manufactured wall paints, which are so easily made dustproof and waterproof.

Samples of wall paper, which had been applied to plastered walls for a year or more, were obtained, and examination under the microscope showed a most uncleanly surface. Cultures were made of these samples, and bacilli of different types were developed in the culture medium in a short time.

Experimental Evidence. That the above conditions could not have existed, had proper wall paints been used, seemed doubtless, and suggested a carefully conducted experiment to prove the relative sanitary values of wall paper and wall paints. A large sheet of fibre board, such as is occasionally used to replace plastered walls, was painted on one side with a high-grade wall paint, three-coat work. A similar sheet was papered on one side with a clean, new wall paper. These test panels were placed where unsanitary conditions, such as dampness, foul odors, and a scarcity of air were present. After a short period of exposure, the panels were taken to the bacteriological laboratory and a small section of the painted surface, about two inches square, as well as a small section of the papered surface of similar size, were removed and used for making cultures. In each case the surface of the section under test was washed with 100 c.c. of distilled, sterilized water. The washings which dripped from the surface were collected in a graduated flask. One c.c. of the washings was used in each case, admixed with bouillon and again with agar-agar. The enormous development of bacteria in the bouillon, treated with the washings from the wall-papered surface, was sufficient evidence to convince one of the greater sanitary value of the wall paint, the washings from which gave a culture practically free from bacteria. The colonies of bacteria shown in the petri-dish test made of the washings from wall paper further supports these findings. It will be noticed that the tests made from the washings of the wall paint show practical absence of bacteria, and was clear, as was the bouillon-solution test of the paint. The washings from the wall paper showed active development of bacteria, both in the bouillon and agar tests.

Development of Bacteria in Bouillon Solutions
Note Practical Freedom ofBacteria in Clear BouillonSolution Treated withWashings from SanitaryWall Paint	Note Milky Appearance ofSolution Due to Heavy Developmentof Bacteria inBouillon Treated withWashings from Wall Paper

From the Conservation Standpoint: It would be of interest to sum up in figures the acreage and cordage of wood that annually is transformed into pulp for the manufacture of wall paper. Unfortunately, there are no available statistics on this subject. It is clear, however, that from the standpoint of conservation the use of wall paints should take precedence over the use of wall paper.

---

INDEX

		PAGE
Abrasion, apparatus for determining resistance to,		[153]
Acid reacting compounds,		[215]
Actinic light tests,		[112]
Adhesive power of Paint Coating,		[104]
Aluminum Silicate,		[62]
American Vermilion,		[64]
Analogies of Paint and Concrete manufacture,		[94]
Analyses of Averages in Atlantic City steel paint test,		[235], [236]
	Corn Oil,	[16]
	Cottonseed Oil,	[15]
	Debloomed Mineral Paint Oil,	[18]
	Iron Oxide Pigments, table,	[63]
	Linseed Oil,	[7]
	Menhaden Oil,	[14]
	Oils used in Washington tests,	[211]
	Petroleum Spirits,	[20]
	Rosin Oil,	[16]
	Soya Bean Oil,	[8]
	Sunflower Oil,	[15]
	Tung Oil,	[12]
	Whale Oil,	[14]
	Wood Turpentine,	[19]
Asbestine,		[55]
Atlantic City fence tests,		[107]
	steel paint tests,	[228]-[235]
	Checking,	[122]
	Gloss,	[122]
	Hiding power,	[122]
	inspection of,	[114]
	Methods used,	[114]
	Results,	[124]
Auto-electrolysis,		[220]
Bacteria in wall paper,		[256]
Barium Sulphate,		[55]
Barytes,		[55]
	and Silica Paints in Pittsburg tests,	[172]
Basic Carbonate-White Lead,		[42]
Benzine,		[20]
Benzol,		[20]
Blanc Fixe,		[60]
Blue Lead, Sublimed,		[47]
Blue Paint for concrete wall, formula,		[215]
Blue paints in Pittsburg tests,		[142]
Boiled Linseed Oil,		[2]
	Driers in,	[28]
Bone Black,		[66]
Calcium Carbonate,		[60]
Calcium Sulphate,		[60]
Carbon Black,		[66]
Cause of rust in steel work,		[220]
Chalking test for laboratory,		[149]
Checking and cracking in Pittsburg tests,		[166]
Checking, in Atlantic City tests,		[122]
China Clay,		[62]
Chrome Green,		[66]
Chrome Yellow,		[64]
Coatings for cement and concrete,		[214]
Colored formulas in North Dakota tests,		[190]
Colors, report of, in Pittsburg tests,		[139]
Combination formulas in inhibitive paints,		[231]
Composite formulas in North Dakota tests,		[190]
	in Pittsburg tests,	[142]
Composition of paints, in steel test,		[232]
Conclusion from Pittsburg tests,		[144]
Concrete primer formula,		[218]
Constants of Pine Oil,		[18]
	Pure Gum Turpentine,	[19]
Co-operative tests of Driers,		[29]-[41]
Corn Oil,		[16]
Cottonseed Oil,		[15]
Damp-proofing and Waterproofing,		[214]
Decay of Lithopone paints,		[124]
Decomposition of Paint,		[122]
Driers, Co-operative tests of,		[29]-[41]
	in Boiled Oil,	[28]
	Tests of Manganese, Lead and Combination, tables,	[24]-[25]
Drying Properties of Oil,		[1], [26], [27]
Elasticity and Strength of Paint Coating,		[102]
Fence tests of paints,		[105]
	Supervision of,	[112]
Film sectioning,		[87]
Film testing results, table,		[80]
Filmometers,		[74]-[79]
Formulafor Blue Paint for concrete wall,		[215]
	Concrete primer,	[218]
	Para Red Paint for concrete wall,	[217]
Formulas of Atlantic City fence test,		[108]
	Tennessee tests,	[202], [204]
	Washington tests,	[208], [211]
Fume Pigments Paints in Pittsburg tests,		[173]
General results of Atlantic City tests,		[128]
Gloss, in Atlantic City tests,		[122]
Graphite,		[66]
Green paints in Pittsburg tests,		[142]
Grinding Pigments,		[87]
Gums as moisture resisters,		[84]
Gypsum,		[60]
Hailstorm, effects of in North Dakota tests,		[185]
Hospital, painting practice,		[254]
House paint tests in North Dakota,		[196]
Hydrocarbon Oils,		[16]
Imperviousness of paint coating,		[100]
Indian Red,		[62]
Inert Pigments, use of,		[99]
Inhibition of rust,		[222]
Iodine Values of Linseed and Mixed Oils, table,		[8]
Iron Oxide Paints,		[64]
Japan driers in tests on steel,		[231]
Laboratory tests, panels for,		[149]
Lampblack,		[66]
Laws of Paint Making,		[93]
Lime action on paint,		[214]
Linoxyn,		[21]
Linseed Oil, boiled,		[2]
	Chemical action of pigments upon,	[91]
	Table of Analyses of Various Types of,	[7]
	tests of Driers with,	[24], [25]
Lithopone,		[53]
	paint in Pittsburg tests,	[136]
	tests at Atlantic City,	[124]
Lumbang Oil,		[12]
Magnesium Silicate,		[55]
Manufacturing Barytes,		[55]
	Blue Lead,	[47]
Manufacturing Bone Black,		[66]
	Paint Pigments,	[42]-[68]
	White Lead,	[42]
Menhaden Oil,		[12]
	Constants of, table,	[14]
Metallic Brown,		[62]
Microscope, use of in paint laboratory,		[86]
Microscopic examination of paint, preparation for,		[86]
	measurements of paint sections,	[89]
Mineral Black,		[68]
	Oils,	[17]
Moisture Absorption, tests in,		[84]
	experiments with various Pigments,	[83]
North Dakota Paints tests,		[182]
	test fence,	[105]
	report of, table,	[193]-[195]
Ochre,		[62]
Oil and Thinner tests,		[202]
Oil, Corn,		[16]
	Cottonseed,	[15]
	Effects of Pigments on,	[90]
	Linseed,	[1]
	Linseed, Analyses of Various Types of, table,	[7]
	Linseed, Iodine Values of, table,	[8]
	Linseed, Tests of Driers with,	[24], [25]
	Lumbang,	[12]
	Menhaden,	[12]
	Menhaden, Constants of, table,	[14]
	Perilla,	[21]
	Pine,	[18]
	Rosin,	[16]
	Soya Bean, and Driers, table,	[9]
	Soya Bean,	[7]
	Chemical Characteristics of, table,	[8]
	Sunflower,	[14]
	Tung,	[9]
	Whale,	[14]
Oils, Constants and Characteristics of,		[1]
	Drying properties of,	[1], [26]
	Hydrocarbon,	[16]
	In Washington paint tests,	[210]
	Iodine Value of Linseed and Mixed, table,	[8]
	Mineral,	[17]
	Moisture resistance of,	[84]
	Oxygen Absorbing qualities,	[21]
Oils, Outline of tests of paints on concrete walls,		[216]
Oxygen Absorption in Oils,		[21]
Paint Coating, Adhesive power of,		[104]
	Elasticity and Strength of,	[102]
	imperviousness of,	[100]
	decomposition of,	[122]
	films, action of water upon,	[223]
	permeability of,	[71]
	Testing machine,	[74]
	preparation of,	[70]
	in Hospitals,	[254]
	making, Laws of,	[93]
	Perry’s Principles of,	[100]
	pigments,	[42]-[69]
	pigments, properties of,	[42]
	preparation for microscopic examination of,	[86]
	tests at North Dakota Experiment Station,	[105]
	at Washington,	[207]-[213]
	supervisors of,	[113]
	woods used on,	[124], [135]
Painting steel plates for tests,		[230]
Paints for cement and concrete surfaces,		[214]
	composition of in steel test,	[233]
	hiding power of,	[111]
	sanitary value of,	[252]
Panels for laboratory tests,		[149]
Para Red formula for concrete wall,		[217]
Paranitraniline paints in Pittsburg tests,		[140]
Paranitraniline Red,		[64]
Perilla Oil,		[21]
Perry’s analogies of paint and concrete manufacture,		[99]
	principles of Paint Making,	[100]
Petroleum Spirits,		[20]
Photomicrographs,		[89], [165]
Pigment contention, the,		[105]
	grinding,	[87]
Pigments,		[42]-[69]
	as stimulators of rust,	[223]
	Chemical action of upon Linseed Oil, table,	[91]
	Effects of on Oil,	[90]
	inert, use of,	[99]
	moisture experiments with, table,	[83]
	percentages of Oil required for grinding,	[68]
	re-enforcing,	[89]
	report of results of steel paint tests,	[236]-[251]
	Water resistance of,	[81]
Pine Oil,		[18]
Pittsburg fence tests,		[107]
Polar Micro-Examinations and Photomicrographs,		[89]
Primer for concrete,		[218]
Properties of Paint Pigments,		[42]
Prussian Blue,		[66]
Red Lead,		[64]
Reductions used in fence tests,		[111]
Re-enforcing Pigments,		[89]
Results of new test at Atlantic City test fence in 1910, table,		[178]-[181]
	Pittsburg tests,	[135]
	steel test plates,	[232]
Rosin Oil,		[16]
Rust, cause of in steel work,		[220]
	inhibition of,	[222]
	stimulation of,	[223]
Sanitary value of paints,		[252]
	wall paints,	[254]
Sienna,		[62]
Silex,		[60]
Silica,		[60]
Silica and Barytes Paints in Pittsburg tests,		[172]
Solvent Naphtha,		[20]
Soya Bean Oil and Driers, table,		[9]
	Chemical Characteristics of, table,	[8]
Steel Paint test, rating report,		[234]
	reports on pigments used,	[236]-[251]
Steel paint, result of tests at Atlantic City,		[234], [235]
Steel, preparation of for paint tests,		[228]
	water contact and paint,	[224]
Structural steel paint tests,		[220]
Sublimed Blue Lead,		[47]
Sublimated White Lead,		[46]
Suction varnish,		[215]
Sunflower Oil,		[14]
	Constants of, table,	[15]
Supervisors of paint tests,		[113]
Table Analysis of Averages in Atlantic City Steel Paint test,		[235], [236]
	Analyses of Corn Oil,	[16]
	Analyses of Debloomed Mineral Paint Oil,	[18]
	Analysis of Iron Oxide Pigments,	[63]
	Analyses of Oils used in Washington tests,	[211]
	Analyses of Petroleum Spirits,	[20]
	Analyses of Rosin Oil,	[16]
TableAnalyses of various types of Linseed Oil,		[7]
	Analyses of wood Turpentine,	[19]
	Atlantic City test fence formula,	[108]
	Chemical Characteristics of Soya Bean Oil,	[8]
	Comparative spreading rates of White Paint in Pittsburg tests,	[148]
	Composition of Blue Lead,	[49]
	Composition of paints in Atlantic City Steel test,	[233]
	Constants of Cottonseed Oil, table,	[15]
	Constants of Menhaden Oil,	[14]
	Constants of Pine Oil,	[18]
	Constants of Sunflower Oil,	[15]
	Constants of Whale Oil,	[14]
	Co-operative drying tests,	[32]-[41]
	Excluding tests for moisture absorbed,	[84]
	Fineness for grinding pigments,	[87]
	Formulas in Tennessee tests,	[204]
	Iodine Value of Linseed Oil and Mixed Oils,	[84]
	Moisture experiments with various pigments,	[83]
	Paint section measurements under microscope,	[89]
	Percentages of Oil required for grinding various dry pigments,	[68]
	Permeability of Paints,	[72]
	Ratings of Atlantic City Steel Paint test,	[234]
	Report of North Dakota test fence,	[193]-[195]
	Results of Atlantic City test fence,	[130], [131]
	Results of new tests at Atlantic City test fence in 1910,	[178]-[181]
	Results of second annual inspection Atlantic City test fence,	[133]
	Results of second annual inspection in Pittsburg tests,	[145]
	Showing action of various pigments upon Linseed Oil,	[91]
	Soya Bean Oil and Driers,	[9]
	Tests of Linseed Oil and Manganese, Lead and Combination Driers,	[24], [25]
Talcose,		[55]
Tennessee Paint tests,		[201]-[206]
Test Fences in Paint Experiments,		[105]
	at Atlantic City,	[114]-[134]
	at Pittsburg,	[135]-[148]
	at Washington,	[207]-[213]
	Cement and concrete,	[214]
	in Tennessee,	[201]-[206]
	laboratory, chalking,	[149]
	North Dakota,	[182]
	of Oil and Thinners,	[202]
	of various pigments in steel paint,	[236]-[251]
	panel sections for,	[149]
	Structural steel paints,	[220]
	Water pigment,	[226]
Thinner, Wood Turpentine as a,		[202]
Tung Oil,		[9]
Tung Varnishes,		[11]
Turpentine,		[18]
Ultramarine Blue,		[66]
Umber,		[62]
Varnishes from Tung Oil,		[11]
Vermilion, American,		[64]
Wall paints,		[252]
Wall paper, defects of,		[255]
Washington Paint tests,		[207]-[213]
Water, action of upon paint films,		[223]
	contact with steel and paint,	[224]
	resistance of Pigments,	[81]
	tests,	[226]
Water-pigment tests,		[226]
Waterproofing and damp-proofing,		[214]
Whale Oil,		[14]
White Lead, Basic Carbonate,		[42]
	Basic Sulphate,	[46]
	Mild Process,	[46]
	Quick Process,	[45]
	in Pittsburg tests,	[139]
	in North Dakota tests,	[190]
	Paints, checking in Pittsburg tests,	[172]
	processes of manufacture of,	[43]-[46]
Whiting,		[60]
Wood Turpentine,		[19]
	experiments with as a thinner,	[202]
Woods used in paint tests,		[124], [135]
Zinc Chromate,		[64]
Zinc Lead White,		[51]
Zinc Oxide,		[51]

Transcriber's Notes:

• Minor typopgraphical errors have been corrected silently; inconsistencies in spelling have not been changed.
• Footnotes have been moved to directly below the table or paragraph to which they refer. Where a single footnote has multiple anchors, there is no backward link.
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• Where there are mutiple footnotes to a single footnote anchor, the reverse link is not implemented. In these cases it is suggested to use the browser back button.
• Tables that were spread over two pages in the original work have been re-combined into a single table.
• Page 25, Table VIII: the header row contains duplicate values (last two columns) that could be typographical errors.
• Page 32-41: some table headers moved or inserted for consistency and better readability.
• Pages 86 and 87 have some section titles followed by numbers. These serve no obvious purpose, but have not been deleted.
• Page 87 (table): row 12 (zinc oxide), column 5: .00037 is probably an error for .0037
• Page 124 contains a footnote without anchor; this has been moved to below the first paragraph of the page as an unnumbered footnote.
• Photos and other illustrations have been edited slightly to show more detail and remove dirt and scratches, except for the (micro)photographs of paint surfaces and other materials; the latter have only been edited slightly to show better contrast.
• Changes made to the text:
  • Page 26: as discolored and turned brown changed to was discolored and turned brown.
  • Page 87: table row 3, 0.00076— changed to 0.00076.
  • Page 94: row 6 (Concrete), } moved down one row as in Paint.
  • Page 124: The note at the bottom of the page has been moved to directly underneath the first paragraph.
  • Page 137: Pittsburgh in caption changed to Pittsburg as elsewhere in text (and in illustration itself).
  • Page 142: prussian blue changed to Prussian blue.
  • Page 161: A.C. changed to A. C. (space added) as elsewhere.
  • Page 177: pages 174 to 177 changed to pages 178 to 180.
  • Pages 197-200: Order of photgraphs changed from vertical to horizontal.
  • Page 211: One footnote anchor * changed to [29] as others in same row.
  • Page 230: 4500 in formula changed to 5400.
  • Page 234: rows for Panel No. 2000: bracket added as elsewhere in table.
  • Page 259 (Index): determinating changed to determining as in text.
  • Page 259 (Index): Derbloomed changed to Debloomed as in text.
  • Page 260 (Index): Filometers changed to Filmometers as in text.
  • Page 261 (Index): Grinding Pigments moved to proper place in alphabetic order.
  • Page 263 (Index): Parilla Oil changed to Perilla Oil as in text.
  • Page 264 (Index): Derbloomed changed to Debloomed as in text.