Paint Technology and Tests

by Henry A. Gardner

Front of Fence showing Present Rearrangement of Panels

TESTS INAUGURATED IN 1907
CHART OF RESULTS OF SECOND ANNUAL INSPECTION OF ATLANTIC CITY TEST FENCE, MAY, 1910

FORMULAS																		REPORT OF INSPECTION				Pan- el Num- ber
For- mu- la Num- ber	Basic Car- bon- ate White Lead		Zinc Ox- ide		Basic Sul- phate White Lead		Zin Lead White	inert pigments
								Calci- um Car- bon- ate		Calci- um Sul- phate	Mag- ne- sium Sili- cate		Bari- um Sul- phate		Silica		Blanc Fixe
																		CHALKING	CHECKING	GENERAL CONDITION	REMARKS
	%		%		%		%	%		%	%		%		%		%
1	30		70		—		—	—		—	—		—		—		—	Very slight	Very slight	Good		1
2	50		50		—		—	—		—	—		—		—		—	Medium	Slight	Very good		3
3	20		50		20		—	10		—	—		—		—		—	Medium	Slight	Good		5
4	48	.5	48	.5	—		—	3	.0	—	—		—		—		—	Very slight	Slight	Good		7
5	22		50		—		—	2		—	26		—		—		—	Slight	Slight	Good		9
6	—		64		—		—	—		—	—		36		—		—	Very slight	Slight	Good		11
7	37		63		—		—	—		—	—		—		—		—	Medium	Slight	Good		13
8	38		48		—		—	—		—	—		—		14		—	Slight	Very slight	Good		15
9	—		73		—		—	2		—	—		—		25		—	Very bad	Deep, with scaling	Poor		17
10	44		46		—		—	5		—	5		—		—		—	Heavy	Deep	Medium		19
11	50		50		—		—	—		—	—		—		—		—	Medium	Medium	Fair		21
12	60		34		—		—	—		6% Inert Pigment							—	Medium	Deep	Fair		23
13	—		27		60		—	3		—	10		—		—		—	Medium	Slight	Very good		25
14	25		25		20		—	5		25	—		—		—		—	Medium	Lateral	Fair		27
15	20		40		—		30	10		—	—		—		—		—	Slight	Visible with naked eye	Poor		29
16	33		33		—		—	—		—	—		34		—		—	Slight	Slight	Good		31
17	40		40		—		—	—		—	3		13		—		4	Medium	Slight	Good		33
18	75		25		—		—	—		—	—		—		—		—	Medium	Slight	Very good		145
19	—		25		75		—	—		—	—		—		—		—	Considerable	Deep	Good		147
20	67	.0	19	.5	—		—	10	.0	—	3	.5	—		—		—	Medium	Slight	Good		149
33	15		30		25		—	—		—	—		—		30		—	Medium	Slight	Very good		176
34	38	.95	33	.58	4	.81	—	19	.48	—	—		1	.59	1	.59	—	Slight	Slight lateral	Good		175
35	37	.51	25	.87	7	.84	—	20	.36	—	—		4	.21	4	.21	—	Slight	Lateral	Good		180
36	100		—		—		—	—		—	—		—		—		—	Considerable	Heavy	Fair	Rough surface	181
37	100		—		—		—	—		—	—		—		—		—	Considerable	Heavy and deep	Poor	Rough surface	182
38	100		—		—		—	—		—	—		—		—		—	More than Panel no. 182	Very deep	Poor		177
39	—		—		—		100	—		—	—		—		—		—	Considerable	Very slight	Good		178
40	—		—		100		—	—		—	—		—		—		—	Heavy	Slight	Good		168
45	—		90		—		—	10		—	—		—		—		—	Slight	Slight	Good		170
46	—		61		—		—	—		—	—		39		—		—	Slight	Medium	Fair		169
47	—		100		—		—	—		—	—		—		—		—	None	Very deep	Poor		172

“There are no pigments possessing greater hiding properties when first used than white leads, but the lack of hiding power on the white lead panels after two years’ exposure was caused by the chalking away of the lead. The superior hiding power of the composite paints was due to the action of the other pigments in these combination paints in preventing the lead from chalking away.

“The Committee finds that the addition of a reasonable percentage of zinc oxide to white lead increases its durability and retards its chalking, renders it whiter, and forms a surface that presents a much better repainting condition. The combinations of white lead and zinc oxide on the Atlantic City Test Fence were in general good condition throughout.

“Corroded white lead, sublimed white lead, zinc oxide, and zinc lead are the standard white opaque pigments. They were all tested on the Atlantic City Fence and it was found that to use any one alone results in inferior protection to the wood. Barium sulphate, silica, asbestine, china clay, and calcium carbonate are the standard crystalline pigments. In the past, the overloading of paints with these crystalline or inert pigments has been the cause of the prejudice that painters have had against their use. It has been established beyond controversy, however, that the use of these pigments, in moderate percentage, combined with any of the standard opaque white pigments, such as white leads, zinc oxide, etc., undoubtedly results in better service from every standpoint and forms the most satisfactory white paint for general outside use. Some of the most perfect painted surfaces on the fence were those made on the above basis as reference to the charted report will show.”

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