VARNISHES
(See also Enamels, Glazes, Oils, Paints, Rust Preventives, Stains, and Waterproofing.)
Varnish is a solution of resinous matter forming a clear, limpid fluid capable of hardening without losing its transparency. It is used to give a shining, transparent, hard, and preservative covering to the finished surface of woodwork, capable of resisting in a greater or less degree the influence of the air and moisture. This coating, when applied to metal or mineral surfaces, takes the name of lacquer, and must be prepared from rosins at once more adhesive and tenacious than those entering into varnish.
The rosins, commonly called gums, suitable for varnish are of two kinds—the hard and the soft. The hard varieties are copal, amber, and the lac rosins. The dry soft rosins are juniper gum (commonly called sandarac), mastic, and dammar. The elastic soft rosins are benzoin, elemi, anime, and turpentine. The science of preparing varnish consists in combining these classes of rosins in a suitable solvent, so that each conveys its good qualities and counteracts the bad ones of the others, and in giving the desired color to this solution without affecting the suspension of the rosins, or detracting from the drying and hardening properties of the varnish.
In spirit varnish (that made with alcohol) the hard and the elastic gums must be mixed to insure tenderness and solidity, as the alcohol evaporates at once after applying, leaving the varnish wholly dependent on the gums for the tenacious and adhesive properties; and if the soft rosins predominate, the varnish will remain, “tacky” for a long time. Spirit varnish, however good and convenient to work with, must always be inferior to oil varnish, as the latter is at the same time more tender and more solid, for the oil in oxidizing and evaporating thickens and forms rosin which continues its softening and binding presence, whereas in a spirit varnish the alcohol is promptly dissipated, and leaves the gums on the surface of the work in a more or less granular and brittle precipitate which chips readily and peels off.
Varnish must be tender and in a manner soft. It must yield to the movements of the wood in expanding or contracting with the heat or cold, and must not inclose the wood like a sheet of glass. This is why oil varnish is superior to spirit varnish. To obtain this suppleness the gums must be dissolved in some liquid not highly volatile like spirit, but one which mixes with them in substance permanently to counteract their extreme friability. Such solvents are the oils of lavender, spike, rosemary, and turpentine, combined with linseed oil. The vehicle in which the rosins are dissolved must be soft and remain so in order to {715} keep the rosins soft which are of themselves naturally hard. Any varnish from which the solvent has completely dried out must of necessity become hard and glassy and chip off. But, on the other hand, if the varnish remains too soft and “tacky,” it will “cake” in time and destroy the effect desired.
Aside from this, close observers if not chemists will agree that for this work it is much more desirable to dissolve these rosins in a liquid closely related to them in chemical composition, rather than in a liquid of no chemical relation and which no doubt changes certain properties of the rosins, and cuts them into solution more sharply than does turpentine or linseed oil. It is a well-known fact that each time glue is liquefied it loses some of its adhesive properties. On this same principle it is not desirable to dissolve varnish rosins in a liquid very unlike them, nor in one in which they are quickly and highly soluble. Modern effort has been bent on inventing a cheap varnish, easily prepared, that will take the place of oil varnish, and the market is flooded with benzine, carbon bisulphide, and various ether products which are next to worthless where wearing and durable properties are desired.
Alcohol will hold in solution only about one-third of its weight in rosins. Turpentine must be added always last to spirit varnish. Turpentine in its clear recently distilled state will not mix with alcohol, but must first be oxidized by exposing it to the air in an uncorked bottle until a small quantity taken therefrom mixes perfectly with alcohol. This usually takes from a month to six weeks. Mastic must be added last of all to the ingredients of spirit varnish, as it is not wholly soluble in alcohol but entirely so in a solution of rosins in alcohol. Spirit varnishes that prove too hard and brittle may be improved by the addition of either of the oils of turpentine, castor seed, lavender, rosemary, or spike, in the proportion required to bring the varnish to the proper temper.
Coloring “Spirit” Varnishes.
Manufacturing Hints.
The Gums Used In Making Varnish.
Venetian turpentine has a tendency to render varnish “tacky” and must be skillfully counteracted if this effect is to be avoided. Benzoin in varnish exposed to any degree of dampness has a {716} tendency to swell, and must in such cases be avoided. Elemi, a fragrant rosin from Egypt, in time grows hard and brittle, and is not so soluble in alcohol as anime, which is highly esteemed for its more tender qualities. Copal is a name given rather indiscriminately to various gums and rosins. The East Indian or African is the tender copal, and is softer and more transparent than the other varieties; when pure it is freely soluble in oil of turpentine or rosemary. Hard copal comes in its best form from Mexico, and is not readily soluble in oil unless first fused. The brilliant, deep-red color of old varnish is said to be based on dragon’s blood, but not the kind that comes in sticks, cones, etc. (which is always adulterated), but the clear, pure tear, deeper in color than a carbuncle, and as crystal as a ruby. This is seldom seen in the market, as is also the tear of gamboge, which, mixed with the tear of dragon’s blood, is said to be the basis of the brilliant orange and gold varnish of the ancients.
Of all applications used to adorn and protect the surface of objects, oil varnishes or lacquers containing hard rosins are the best, as they furnish a hard, glossy coating which does not crack and is very durable even when exposed to wind and rain.
To obtain a varnish of these desirable qualities the best old linseed oil, or varnish made from it, must be combined with the residue left by the dry distillation of amber or very hard copal. This distillation removes a quantity of volatile oil amounting to one-fourth or one-fifth of the original weight. The residue is pulverized and dissolved in hot linseed-oil varnish, forming a thick, viscous, yellow-brown liquid, which, as a rule, must be thinned with oil of turpentine before being applied.
Hard rosin oil varnish of this sort may conveniently be mixed with the solution of asphalt in the oil of turpentine with the aid of the simple apparatus described below, as the stiffness of the two liquids makes hand stirring slow and laborious. A cask is mounted on an axle which projects through both heads, but is inclined to the axis of the cask, so that when the ends of the axle are set in bearings and the cask is revolved, each end of the cask will rise and fall alternately, and any liquid which only partly fills the cask will be thoroughly mixed and churned in a short time. The cask is two-thirds filled with the two thick varnishes (hard rosin in linseed oil and asphalt in the oil of turpentine) in the desired proportion, and after these have been intimately mixed by turning the cask, a sufficient quantity of rectified oil of turpentine to give proper consistence is added and the rotation is continued until the mixture is perfectly uniform.
To obtain the best and most durable result with this mixed oil, rosin, and asphalt varnish it is advisable to dilute it freely with oil of turpentine and to apply 2 or 3 coats, allowing each coat to dry before the next is put on. In this way a deep black and very glossy surface is obtained which cannot be distinguished from genuine Japanese lacquer.
Many formulas for making these mixed asphalt varnishes contain rosin—usually American rosin. The result is the production of a cheaper but inferior varnish. The addition of such soft rosins as elemi and copaiba, however, is made for another reason, and it improves the quality of the varnish for certain purposes. Though these rosins soften the lacquer, they also make it more elastic, and therefore more suitable for coating leather and textile fabrics, as it does not crack in consequence of repeated bending, rolling, and folding.
In coloring spirit varnish the alcohol should always be colored first to the desired shade before mixing with the rosin, except where ivory or bone black is used. If the color is taken from a gum, due allowance for the same must be made in the rosins of the varnish. For instance, in a varnish based on mastic, 10 parts, and tender copal, 5 parts, in 100 parts, if this is to be colored with, say, 8 parts of dragon’s blood (or any other color gum), the rosins must be reduced to mastic, 8 parts, and tender copal, 4 parts. Eight parts of color gum are here equivalent to 3 parts of varnish rosin. This holds true with gamboge, aloes, myrrh, and the other gum rosins used for their color. This seeming disproportion is due to the inert matter and gum insoluble in alcohol, always present in these gum rosins.
Shellac Varnish.
Various impurities held in suspension in shellac varnish may be entirely precipitated by the gradual addition of some {717} crystals of oxalic acid, stirring the varnish to aid their solution, and then setting it aside overnight to permit the impurities to settle. No more acid should be used than is really necessary.
Rules For Varnishing.
2. Varnishing must be done only on smooth, clean surfaces, if a fine, mirror-like gloss is desired.
3. Varnish must be poured only into clean vessels, and from these never back into the stationary vessels, if it has been in contact with the brush. Use only dry brushes for varnishing, which are not moist with oil of turpentine or linseed oil or varnish.
4. Apply varnishes of all kinds as uniformly as possible; spread them out evenly on the surfaces so that they form neither too thick nor too thin a layer. If the varnish is put on too thin the coating shows no gloss; if applied too thick it does not get even and does not form a smooth surface, but a wavy one.
5. Like all oil-paint coatings, every coat of varnish must be perfectly dry before a new one is put on; otherwise it is likely that the whole work will show cracks. The consumer of varnish is only too apt to blame the varnish for all defects which appear in his work or develop after some time, although this can only be proven in rare cases. As a rule, the ground was not prepared right and the different layers of paint were not sufficiently dry, if the surfaces crack after a comparatively short time and have the appearance of maps. The cracking of paint must not be confounded with the cracking of the varnish, for the cracking of the paint will cause the varnish to crack prematurely. The varnish has to stand more than the paint; it protects the latter, and as it is transparent, the defects of the paint are visible through the varnish, which frequently causes one to form the erroneous conclusion that the varnish has cracked.
6. All varnish coatings must dry slowly, and during the drying must be absolutely protected from dust, flies, etc., until they have reached that stage when we can pass the back of the hand or a finger over them without sticking to it.
The production of faultless varnishing in most cases depends on the accuracy of the varnisher, on the treatment of his brush, his varnish pot, and all the other accessories. A brush which still holds the split points of the bristles never varnishes clear; they are rubbed off easily and spoil the varnished work. A brush which has never been used does not produce clean work; it should be tried several times, and when it is found that the varnishing accomplished by its use is neat and satisfactory it should be kept very carefully.
The preservation of the brush is thus accomplished: First of all do not place it in oil or varnish, for this would form a skin, parts of which would adhere to it, rendering the varnished surface unclean and grainy; besides these skins there are other particles which accumulate in the corners and cannot be removed by dusting off; these will also injure the work. In order to preserve the brush properly, insert it in a glass of suitable size through a cork in the middle of which a hole has been bored exactly fitting the handle. Into the glass pour a mixture of equal parts of alcohol and oil of turpentine, and allow only the point of the brush to touch the mixture, if at all. If the cork is air-tight the brush cannot dry in the vapor of oil of turpentine and spirit. From time to time the liquids in the glass should be replenished.
If the varnish remains in the varnish receptacle, a little alcohol may be poured on, which can do the varnish no harm. At all events the varnish will be prevented from drying on the walls of the vessel and from becoming covered by a skin which is produced by the linseed oil, and which indicates that the varnish is both fat and permanent. No skin forms on a meager varnish, even when it drys thick.
After complete drying of the coat of varnish it sometimes happens that the varnish becomes white, blue, dim, or blind. If varnish turns white on exposure to the air the quality is at fault. The varnish is either not fat enough or it contains a rosin unsuitable for exterior work (copal). The whitening occurs a few days after the drying of the varnish and can be removed only by rubbing off the varnish.
Preventing Varnish From Crawling.
Amber Varnish.
Asphalt Varnishes.
But even solutions of the best Syrian asphalt in the purest oil of turpentine, if they are allowed to stand undisturbed for a long time in large vessels, deposit a thick, semi-fluid precipitate which a large addition of oil of turpentine fails to convert into a uniform thin liquid. It may be assumed that this deposit consists of an insoluble or nearly insoluble part of the asphalt which, perhaps, has been deprived of solubility by the action of light. Hence, in order to obtain a uniform solution, this thick part must be removed. This can be done, though imperfectly, by carefully decanting the solution after it has stood for a long time in large vessels. This tedious and troublesome process may be avoided by filtering the solution as it is made, by the following simple and quite satisfactory method: The solution is made in a large cask, lying on its side, with a round hole about 8 inches in diameter in its upper bilge. This opening is provided with a well-fitting cover, to the bottom of which a hook is attached. The asphalt is placed in a bag of closely woven canvas, which is inclosed in a second bag of the same material. The diameter of the double bag, when filled, should be such as to allow it to pass easily through the opening in the cask, and its length such that, when it is hung on the hook, its lower end is about 8 inches above the bottom of the cask. The cask is then filled with rectified oil of turpentine, closed, and left undisturbed for several days. The oil of turpentine penetrates into the bag and dissolves the asphalt, and the solution, which is heavier than pure oil of turpentine, exudes through the canvas and sinks to the bottom of the cask. Those parts of the asphalt which are quite insoluble, or merely swell in the oil of turpentine, cannot pass through the canvas, and are removed with the bag, leaving a perfect solution. When all soluble portions have been dissolved, the bag, with the cover, is raised and hung over the opening to drain. If pulverized asphalt has {719} been used the bag is found to contain only a small quantity of semi-fluid residue. This, thinned with oil of turpentine and applied with a stiff brush and considerable force, forms a thick, weather-resisting, and very durable coating for planks, etc.
The proportion of asphalt to oil of turpentine is so chosen as to produce, in the cask, a pretty thick varnish, which may be thinned to any desired degree by adding more turpentine. For use, it should be just thick enough to cover bright tin and entirely conceal the metal with a single coat. When dry, this coat is very thin, but it adheres very firmly, and continually increases in hardness, probably because of the effect of light. This supposition is supported by the difficulty of removing an old coat of asphalt varnish, which will not dissolve in turpentine even after long immersion, and usually must be removed by mechanical means.
For a perfect, quick-drying asphalt varnish the purest asphalt must be used, such as Syrian, or the best Trinidad. Trinidad seconds, though better than some other asphalts, yield an inferior varnish, owing to the presence of impurities.
Of artificial asphalt, the best for this purpose is the sort known as “mineral caoutchouc,” which is especially suitable for the manufacture of elastic dressings for leather and other flexible substances. For wood and metal it is less desirable, as it never becomes as hard as natural asphalt.
Formulas:
I.—A solution of 1 part of caoutchouc in 16 parts of oil of turpentine or kerosene is mixed with a solution of 16 parts of copal in 8 parts of linseed-oil varnish. To the mixture is added a solution of 2 parts of asphalt in 3 or 4 parts of linseed-oil varnish diluted with 8 or 10 parts of oil of turpentine, and the whole is filtered. This is a fine elastic varnish.
II.—Coal-tar asphalt, American asphalt, rosin, benzine, each 20 parts; linseed-oil varnish, oil of turpentine, coal-tar oil, each 10 parts; binoxide of manganese, roasted lampblack, each 2 parts. The solid ingredients are melted together and mixed with the linseed-oil varnish, into which the lampblack has been stirred, and, finally, the other liquids are added. The varnish is strained through tow.
Bicycle Varnish.
Bicycle Dipping Varnish
Black Varnishes.
Black Japanese Varnish.
| II.— | Shellac | 4 parts |
|---|---|---|
| Borax | 2 parts | |
| Glycerine | 2 parts | |
| Aniline black | 5 parts | |
| Water | 50 parts |
Dissolve the borax in the water, add {720} the shellac, and heat until solution is effected; then add the other ingredients. This is a mat-black varnish.
For Blackboards.
Bookbinders’ Varnishes.—
| I Per Cent | II Per Cent | III Per Cent | IV Per Cent | V Per Cent | |
|---|---|---|---|---|---|
| Shellac | 14.5 | 6.5 | 13.5 | 6.3 | 8.3 |
| Mastic | 6.0 | 2.0 | — | — | 1.1 |
| Sandarac | 6.0 | 13.0 | — | 1.3 | 1.1 |
| Camphor | 1.0 | — | 0.5 | 1.5 | — |
| Benzoin | — | — | — | — | 13.7 |
| Alcohol | 72.5 | 78.5 | 86.0 | 79.2 | 75.8 |
Scent with oil of benzoin, of lavender, or of rosemary. Other authors give the following recipes:
| VI Per Cent | VII Per Cent | VIII Per Cent | IX Per Cent | |
|---|---|---|---|---|
| Blond shellac | 11.5 | 13.0 | 9.0 | — |
| White shellac | 11.5 | — | — | — |
| Camphor | — | 0.7 | — | — |
| Powdered sugar | — | 0.7 | — | — |
| Sandarac | — | — | 18.0 | 6.6 |
| Mastic | — | — | — | 13.0 |
| Venice turpentine | — | — | 2.0 | 6.6 |
| Alcohol | 77.0 | 85.6 | 71.0 | 73.8 |
All solutions may be prepared in the cold, but the fact that mastic does not dissolve entirely, must not be lost sight of.
Bottle Varnish.
Amber-colored bottles for substances acted upon by the actinic rays of light may be obtained from almost any manufacturer of bottles.
Can Varnish.
Copal Varnish.
I.—Melt 8 pounds best copal and mix with 20 pounds very clear matured oil. Then boil 4 to 5 hours at moderate heat until it draws threads; now mix with 35 pounds oil of turpentine, strain and keep for use. This varnish dries rather slowly, therefore varnishers generally mix it one-half with another varnish, which is prepared by boiling for 4 hours, 20 pounds clear linseed oil and 8 pounds very pure, white anime rosin, to which is subsequently added 35 pounds oil of turpentine.
II.—Mix the following two varnishes:
(a) Eight pounds copal, 10 pounds linseed oil, 1/2 pound dried sugar of lead, 35 pounds oil of turpentine.
(b) Eight pounds good anime rosin, 10 pounds linseed oil, 1/4 pound zinc vitriol, 35 pounds oil of turpentine. Each of these two sets is boiled separately into varnish and strained, and then both are mixed. This varnish dries in 6 hours in winter, and in 4 hours in summer. For old articles which are to be re-varnished black, it is very suitable.
Elastic Limpid Gum Varnishes.
II.—Dissolve 1 part of the desiccated rubber in 8 parts of petroleum ether (benzine) and add 2 parts of fat copal varnish and stir in. Or, cover 2 parts of dried rubber with 1 part of ether; let stand for several days, or until the rubber has taken up as much of the ether as it will, then liquefy by standing in a vessel of moderately warm water. While still warm, stir in 2 parts of linseed oil, cut with 2 parts of turpentine oil.
Enamel Varnishes:
Antiseptic Enamel.
Bath-tub Enamel Unaffected By Hot Water.
The priming coat should be white lead thinned with turpentine, with only just sufficient linseed oil to bind it. After this is thoroughly dry, apply one or more coats of special bath-tub enamel, or a gloss paint made by mixing coach colors ground in Japan with hard-drying varnish of the best quality. Most first-class manufacturers have special grades that will stand hot water.
II.—The following preparation produces a brilliant surface on metals and is very durable, resisting the effect of blows without scaling or chipping off, and being therefore highly suitable for cycles and any other articles exposed to shock:
For the manufacture of 44 gallons, 11 pounds of red copper, 8.8 pounds of yellow copper, 4.4 pounds of hard steel, and 4.4 pounds of soft steel, all in a comminuted condition, are well washed in petroleum or mineral spirit, and are then treated with concentrated sulphuric acid in a lead-lined vessel, with continued stirring for 2 hours. After 12 hours’ rest the sulphuric acid is neutralized with Javel extract, and the fine powder left in the vessel is passed through a silk sieve to remove any fragments of metal, then ground along with linseed oil, ivory black, and petroleum, the finely divided mass being afterwards filtered through flannel and incorporated with a mixture of Bombay gum, 22 pounds; Damascus gum, 11 pounds; Judea bitumen, 22 pounds; Norwegian tar rosin, 11 pounds; and 11 pounds of ivory black ground very fine in refined petroleum. When perfectly homogeneous the mass is again filtered, and is then ready for use. It is laid on with a brush, and then fixed by exposure to a temperature of between 400° and 800° F. The ivory black may be replaced by other coloring matters, according to requirements.
A Color Enamel.
Cold Enameling.
White.—White lead or flake white.
Red.—Carmine or cinnabar (vermilion).
Blue.—Ultramarine or Prussian blue.
Green.—Scheele’s green or Schweinfurt green.
Brown.—Umber.
Yellow.—Ocher or chrome yellow.
The different shades are produced by mixing the colors.
Enamel For Vats, Etc.
The top enamel (hard) consists of 500 parts shellac, 125 parts French oil of turpentine, and 3,500 parts spirit (90 per cent). Boiling in the water bath until the solution appears clear can only be of advantage. According to the thickness desired, one may still dilute in the cold with high-strength spirit. Tinting may be done, as desired, with earth colors, viz., coffee brown with umber, red with English red, yellow with ocher, silver gray with earthy cerussite, and some lampblack. Before painting, dry out the vats and putty up the joints with a strip of dough which is prepared from ground enamel and finely sifted charcoal or brown coal ashes, and apply the enamel after the putty is dry. The varnish dries quickly, is odorless and tasteless, and extraordinarily durable. If a little annealed soot black is added to this vat enamel, a fine iron varnish is obtained which adheres very firmly. Leather (spattering leather on carriages) can also be nicely varnished with it.
Finishing Enamel For White Furniture.
Quick-drying Enamel Colors.
In a closed stirrer or rolling cask place 21.5 parts, by weight, of finely powdered pale French rosin, 24 1/2 parts, by weight, of Manila copal, as well as 35 parts, by weight, of denaturized spirit (95 per cent), causing the cask or the stirrer to rotate until all the gum has completely dissolved, which, according to the temperature of the room in which the stirrer is and the hardness of the gums, requires 24 to 48 hours. When the gums are entirely dissolved add to the mixture a solution of 21 1/2 parts, by weight, of Venice oil turpentine in 0.025 parts, by weight, of denaturized spirit of 95 per cent, allowing the stirrer to run another 2 to 3 hours. For the purpose of removing any impurities present or any undissolved rosin from the varnish, it is poured through a hair sieve or through a threefold layer of fine muslin (organdie) into suitable tin vessels or zinc-lined barrels for further clarification. After 10 to 14 days the varnish is ready for use. By grinding this varnish with the corresponding dry pigments the desired shades of color may be obtained; but it is well to remark that chemically pure zinc white cannot be used with advantage because it thickens and loses its covering power. The grinding is best carried out twice on an ordinary funnel mill. Following are some recipes:
I.—Enamel White.—Lithopone, 2 parts, by weight; white lead, purest, 1/2 part, by weight; varnish, 20 parts, by weight.
II.—Enamel Black.—Ivory black, 2 parts, by weight; Paris blue, 0.01 part, by weight; varnish, 23 parts, by weight.
III.—Pale Gray.—Graphite, 2 parts, by weight; ultramarine, 0.01 part, by weight; lithopone, 40 parts, by weight; varnish, 100 parts, by weight.
IV.—Dark Gray.—Graphite, 3 parts, by weight; ivory black, 2 parts, by weight; lithopone, 40 parts, by weight; varnish, 110 parts, by weight. {723}
V.—Chrome Yellow, Pale.—Chrome yellow, 2 parts, by weight; lithopone, 2 parts, by weight; varnish, 40 parts, by weight; benzine, 1 1/2 parts, by weight.
VI.—Chrome Yellow, Dark.—Chrome yellow, dark, 2 parts, by weight; chrome orange, 1/8 part, by weight; lithopone, 1 part, by weight; varnish, 35 parts, by weight; benzine, 1 part, by weight.
VII.—Pink, Pale.—Carmine, 1/2 part, by weight; lithopone, 15 parts, by weight; varnish, 40 parts, by weight; benzine, 1 1/2 parts, by weight.
VIII.—Pink, Dark.—Carmine, 1/2 part, by weight; Turkey red, 1 part, by weight; lithopone, 15 parts, by weight; varnish, 40 parts, by weight.
IX.—Turkey Red.—Turkey red, pale, 2 parts, by weight; lithopone, 1 part, by weight; Turkey red, dark, 1 part, by weight; white lead, pure, 1/2 part, by weight; varnish, 18 parts, by weight; benzine, 1/2 part, by weight.
X.—Flesh Tint.—Chrome yellow, pale, 1 1/2 parts, by weight; graphite, 1/8 part, by weight; lithopone, 15 parts, by weight; Turkey red, pale, 2 parts, by weight; varnish, 42 parts, by weight; benzine, 1/2 part, by weight.
XI.—Carmine Red.—Lead sulphate, 5 parts, by weight; Turkey red, pale, 6 parts, by weight; carmine, 1 1/2 parts, by weight; orange minium, 3 parts, by weight; vermilion, 2 parts, by weight; varnish, 50 parts, by weight; benzine, 1 1/2 parts, by weight.
XII.—Sky Blue.—Ultramarine, 5 parts, by weight; lithopone, 5 parts, by weight; ultramarine green, 0.05 parts, by weight; varnish, 30 parts, by weight; benzine, 1 part, by weight.
XIII.—Ultramarine.—Ultra blue, 5 parts, by weight; varnish, 12 parts, by weight; benzine, 1/2 part, by weight.
XIV.—Violet.—Ultramarine, with red tinge, 10 parts, by weight; carmine, 0.5 parts, by weight; varnish, 25 parts, by weight.
XV.—Azure.—Paris blue, 10 parts, by weight; lithopone, 100 parts, by weight; varnish, 300 parts, by weight.
XVI.—Leaf Green.—Chrome green, pale, 5 parts, by weight; varnish, 25 parts, by weight; benzine, 1/2 part, by weight.
XVII.—Silk Green.—Silk green, 10 parts, by weight; chrome yellow, pale, 1/2 part, by weight; lead sulphate, 5 parts, by weight; varnish, 30 parts, by weight; benzine, 1/2 part, by weight.
XVIII.—Brown.—English red, 10 parts, by weight; ocher, light, 3 parts, by weight; varnish, 30 parts, by weight; benzine, 1/2 part, by weight.
XIX.—Ocher.—French ocher, 10 parts, by weight; chrome yellow, dark, 1/2 part, by weight; varnish, 30 parts, by weight; benzine, 1/2 part, by weight.
XX.—Chocolate.—Umber, 10 parts, by weight; Florentine lake, 1/8 part, by weight; varnish, 25 parts, by weight; benzine, 1/2 part, by weight.
XXI.—Terra Cotta.—Chrome yellow, pale, 10 parts, by weight; Turkey red, dark, 3 parts, by weight; varnish, 35 parts, by weight.
XXII.—Olive, Greenish.—French ocher, 5 parts, by weight; Paris blue, 1/2 part, by weight; graphite, 1/2 part, by weight; varnish, 25 parts, by weight; lithopone, 5 parts, by weight.
XXIII.—Olive, Brownish.—Chrome orange, 5 parts, by weight; Paris blue, 2 parts, by weight; lead sulphate, 10 parts, by weight; English red, 1 part, by weight; varnish, 40 parts, by weight; benzine, 1 1/2 parts, by weight.
XXIV.—Olive, Reddish.—Turkey red, dark, 75 parts, by weight; sap green, 75 parts, by weight; ocher, pale, 5 parts, by weight; varnish, 300 parts, by weight; benzine, 1 1/2 parts, by weight.
Engravers’ Varnishes.
In copper-plate engraving the plate must be covered with a dark-colored coating which, though entirely unaffected by the etching fluid, must be soft enough to allow the finest lines to be drawn with the needle and must also be susceptible of complete and easy removal when the etching is finished. Varnishes which possess these properties are called “etching grounds.” They are made according to various formulas, but in all cases the principal ingredient is asphalt, of which only the best natural varieties are suitable for this purpose. Another common ingredient is beeswax, or tallow.
Etching grounds are usually made in small quantities, at a single operation, by melting and stirring the solid ingredients together and allowing the mass to cool in thin sheets, which are then dissolved in oil of turpentine. The plate is coated uniformly with this varnish through which the engraver’s tool readily penetrates, laying bare the metal beneath. After the lines thus drawn have been etched by immersing the plate in acid, the varnish is washed off with oil of turpentine.
The following formulas for etching grounds have been extensively used by engravers: {724}
| I | II | III | IV | |
|---|---|---|---|---|
| Yellow wax | 50 | 30 | 110 | 40 parts |
| Syrian asphalt | 20 | 20 | 25 | 40 parts |
| Rosin | — | — | — | 20 parts |
| Amber | — | — | 20 | — parts |
| Mastic | 25 | 25 | 25 | — parts |
| Tallow | — | — | — | 2 parts |
| Bergundy pitch | — | — | — | 10 parts |
Floor Varnishes.
| I.— | Manila copal, spirit-soluble | 12 parts |
|---|---|---|
| Ruby shellac, powdered | 62 parts | |
| Venice, turpentine | 12 parts | |
| Spirit, 96 per cent | 250 parts |
The materials are dissolved cold in a covered vat with constant stirring, or better still, in a stirring machine, and filtered. For the pale shades take light ocher; for dark ones, Amberg earth, which are well ground with the varnish in a paint mill.
II.—Shellac, A C leaf, 1.2 parts; sandarac, 8 parts; Manila copal, 2 parts; rosin, 5 parts; castor or linoleic acid or wood oil acid, 1.50 parts; spirit (96 per cent), 65 parts.
French Varnish.
For red, use 1 part of eosin to 49 parts of the bleached shellac solution. For blue, use 1 part of aniline blue to 24 parts of the bleached shellac solution, as the orange shellac solution would impart a greenish cast. For green, use 1 part of aniline green (brilliant green) to 49 parts of the orange shellac solution. For yellow, use either 2 parts of extract of turmeric or 1 part of gamboge to 24 parts of the solution, or 1 part of aniline yellow to 49 parts of the solution. For golden yellow, use 2 parts of gamboge and 1 part of dragon’s blood to 47 parts of the orange shellac solution. The gamboge and dragon’s blood should be dissolved first in a little alcohol.
Golden Varnishes.—
| I.— | Powdered benzoin | 1 part |
|---|---|---|
| Alcohol enough to make | 10 parts. | |
| Pure saffron, roughly broken up, about 6 threads to the ounce. | ||
Macerate 3 days and filter. Vary the quantity of saffron according to the shade desired. Mastic and juniper gum may be added to this varnish if a heavier body is desired.
II.—Benzoin, juniper gum, gum mastic, equal parts.
Dissolve the gums in 9 times their weight of alcohol (varied more or less according to the consistency wanted), and color to the desired shade with threads of pure saffron. This varnish is very brilliant and dries at once.
India-rubber Varnishes.
II.—Dissolve 7 pounds of India rubber in 25 pounds of oil of turpentine. By continued heating dissolve 14 pounds of rosin in the mixture. Color while hot with 3 pounds of lampblack.
Inlay Varnish.—
| Ozokerite | 17 parts |
| Carnauba wax | 3 parts |
| Turpentine oil | 15 parts |
Melt the ozokerite and Carnauba wax, then stir in the turpentine oil. This varnish is applied like a polish and imparts to the wood a dark natural color and a dull luster.
Japanning Tin.
After these preliminaries, a paint of the shade desired, ground in linseed oil, is applied. For brown, umber may be used.
When the paint has been satisfactorily applied it should be hardened by heating, and then smoothed down by rubbing with ground pumice stone applied gently by means of a piece of felt moistened with water. To be done well, this requires care and patience, and, it might be added, some experience.
The vessel is next coated with a varnish, made by the following formula:
| Turpentine spirit | 8 ounces |
| Oil of lavender | 6 ounces |
| Camphor | 1 drachm |
| Bruised copal | 2 ounces |
Perhaps some other good varnish would give equally satisfactory results.
After this the vessel is put in an oven and heated to as high a temperature as it will bear without causing the varnish to {725} blister or run. When the varnish has become hard, the vessel is taken out and another coat is put on, which is submitted to heat as before. This process may be repeated till the judgment of the operator tells him that it is no longer advisable.
Some operators mix the coloring matter directly with the varnish; when this is done, care should be taken that the pigment is first reduced to an impalpable powder, and then thoroughly mixed with the liquid.
Label Varnishes.
| I.— | Sandarac | 3 ounces av. |
|---|---|---|
| Mastic | 3/4 ounce av. | |
| Venice turpentine | 150 grains | |
| Alcohol | 16 fluidounces |
Macerate with repeated stirring until solution is effected, and then filter.
The paper labels are first sized with diluted mucilage, then dried, and then coated with this varnish. If the labels have been written with water-soluble inks or color, they are first coated with 2 coats of collodion, and then varnished.
II.—The varnished labels of stock vessels often suffer damage from the spilling of the contents and the dripping after much pouring.
Formalin gelatin is capable of withstanding the baneful influence of ether, benzine, water, spirit of wine, oil, and most substances. The following method of applying the preservative is recommended: Having thoroughly cleaned the surface of the vessel, paste the label on and allow it to dry well. Give it a coat of thin collodion to protect the letters from being dissolved out or caused to run, then after a few minutes paint over it a coat of gelatin warmed to fluidity—5 to 25—being careful to cover in all the edges. Just before it solidifies go over it with a tuft of cotton dipped into a 40 per cent formalin solution. It soon dries and becomes as glossy as varnish, and may be coated again and again without danger of impairing the clear white of the label or decreasing its transparency.
Leather Varnishes.
II.—Caoutchouc, 1 part; petroleum, 1 part; carbon bisulphide, 1 part; shellac, 4 parts; bone black, 2 parts; alcohol, 20 parts. First the caoutchouc is brought together with carbon bisulphide in a well-closed bottle and stood aside for a few days. As soon as the caoutchouc is soaked add the petroleum and the alcohol, then the finely powdered shellac, and heat to about 125° F. When the liquid appears pretty clear, which indicates the solution of all substances, the bone black is added by shaking thoroughly and the varnish is at once filled in bottles which are well closed. This pouch composition excels in drying quickly and produces upon the leather a smooth, deep black coating, which possesses a certain elasticity.
Metal Varnishes.
The purpose of these varnishes is to protect the metals from oxidation and to render them glossy.
Aluminum Varnish.
Brass Varnishes Imitating Gold.
II.—Reduce to powder, 160 parts, by weight, of turmeric of best quality, and pour over it 2 parts, by weight, of saffron, {726} and 1.700 parts, by weight, of spirit; digest in a warm place 24 hours, and filter. Next dissolve 80 parts, by weight, of dragon’s blood; 80 parts, by weight, of sandarac; 80 parts, by weight, of elemi gum; 50 parts, by weight, of gamboge; 70 parts, by weight, of seedlac. Mix these substances with 250 parts, by weight, of crushed glass, place them in a flask, and pour over this mixture the alcohol colored as above described. Assist the solution by means of a sand or water bath, and filter at the close of the operation. This is a fine varnish for brass scientific instruments.
Bronze Varnishes.
Brown Varnish.
Copper Varnishes.
I.—One hundred and ten parts of sandarac and 30 parts of rosin, dissolved in sufficient quantity of alcohol; 5 parts of glycerine are to be added.
| II.— | Sandarac | 10 parts |
|---|---|---|
| Rosin | 3 parts | |
| Glycerine | 1/2 part | |
| Alcohol, a sufficient quantity. | ||
Dissolve the two rosins in sufficient alcohol and add the glycerine.
Decorative Metal Varnishes.—
| I Per Cent | II Per Cent | III Per Cent | IV Per Cent | |
|---|---|---|---|---|
| Seed lac | 11.5 | — | — | — |
| Amber | 7.6 | — | — | 13.5 |
| Gamboge | 7.6 | — | — | — |
| Dragon’s blood | 0.18 | — | — | — |
| Saffron | 0.16 | — | — | — |
| Sandarac | — | 11.2 | 15.9 | 16.6 |
| Mastic | — | 6.5 | 14.0 | 3.4 |
| Elemi | — | 3.3 | — | — |
| Venice turpentine | — | — | 1.0 | 3.4 |
| Camphor | — | 1.5 | — | — |
| Aloe | — | — | 7.0 | — |
| Alcohol | 72.96 | 77.5 | 66.1 | 63.2 |
As will be seen, only natural colors are used. The so-called “gold lacquer” is composed as follows: Sandarac, 6.25 parts; mastic, 3 parts; shellac, 12.5 parts; Venice turpentine, 2.5 parts; aloe, 0.75 parts; gamboge, 3 parts; alcohol, 72 parts. The solution is filtered. Applied in a thin coating this varnish shows a handsome golden shade. Other metal varnishes have the following composition:
| V Per Cent | VI Per Cent | VII Per Cent | |
|---|---|---|---|
| Shellac | 17.5 | — | 18.0 |
| Yellow acaroid gum | 13.1 | 25.0 | — |
| Manila | — | 8.0 | 9.0 |
| Alcohol | 69.4 | 67.0 | 63.0 |
{727}
Gold Varnish.
II.—A varnish which will give a splendid luster, and any gold color from deep red to golden yellow, is prepared by taking 50 ounces pale shellac, 15 pounds Florentine lake (precipitated from cochineal or redwood decoction by alum onto strach, kaolin, or gypsum), 25 ounces of sandalwood, and 8 ounces of dragon’s blood. These in fine powder are dissolved on the water bath, in 500 ounces rectified spirit. The spirit must boil and remain, with occasional shaking, for 2 to 3 hours on the bath. Then cool and decant. In the meantime heat in another flask on the bath 30 ounces of gamboge in 500 ounces of the same spirit. The two liquids are mixed until the right color needed for the particular purpose in hand is obtained. Dilute with spirit if too thick. The addition of a little picric acid gives a greenish-yellow bronze but makes the varnish very liable to explode. These varnishes are applied to gently warmed surfaces with a soft bristle brush.
Gold Varnish For Tin.
Iron Varnishes.
II.—Shellac, 15 pounds; Siam benjamin, 13 pounds; alcohol, 80 pounds; formylchloride, 20 pounds.
III.—Sierra Leone copal, 6 pounds; dammar, 18 pounds; oleic acid, 3 pounds; alcohol, 40 pounds; oil of turpentine, 20 pounds; formylchloride, 15 pounds. The formylchloride not only effects the rapid drying necessary to prevent the varnish gravitating into hollows, but enables the alcohol to make a perfect solution of the rosin. The varnishes are excessively volatile, and must be stored accordingly.
Stove Varnishes.—
| Shellac | 12 parts |
| Manila copal | 14 parts |
| Rosin | 12 parts |
| Gallipot | 2 parts |
| Benzoin | 1 part |
| Lampblack | 5 parts |
| Nigrosin, spirit-soluble | 1 1/2 parts |
| Alcohol | 250 parts |
Tin Varnishes.
In 75 parts of alcohol dissolve 15 parts of shellac, 2 parts of Venice turpentine, and 8 parts of sandarac.
II.—For Trays and Other Tinware.—The ground is prepared by adding to the white lead the tinting colors ground in good rubbing varnish and half oil of turpentine. For drier an admixture of “terebine” is recommended. With this lean and dull paint, coat the tins 2 or 3 times and blend. Next, grain with water or vinegar glaze, and varnish with pure Zanzibar copal varnish, or finest amber table-top varnish. There are other tried methods for varnishing tin, which are applicable for new goods, manufactured in large quantities, while they are less advantageous for the restoration of old, repeatedly used articles.
Varnish Substitutes.
A substitute for varnish is produced by adding to 100 parts of casein 10 to 25 parts of a 1 to 10 per cent soap solution and then 20 to 25 parts of slaked lime. The mixture is carefully kneaded until a perfectly homogeneous mass results. Then gradually add 25 to 40 parts of turpentine oil and sufficient {728} water for the mass to assume the consistency of varnish. If it is desired to preserve it for some time a little ammonia is added so that the casein lime does not separate. The surrogate is considerably cheaper than varnish and dries so quickly that paint ground with it may be applied twice in quick succession.
Zapon Varnishes.
For the production of zapon or celluloid varnish, pour 20 parts of acetone over 2 parts of colorless celluloid waste, allowing it to stand for several days in a closed vessel, stirring frequently until the whole has dissolved into a clear, thick mass. Admix 78 parts of amyl acetate and clarify the zapon varnish by allowing it to settle for weeks.
VARNISH, HOW TO POUR OUT: See Castor Oil.
VARNISHES, INSULATING: See Insulation.
VARNISHES, PHOTOGRAPHIC RETOUCHING: See Photography.
VARNISH REMOVERS: See Cleaning Preparations and Methods.
VASELINE STAINS, TO REMOVE FROM CLOTHING: See Cleaning Preparations and Methods.