Part 133

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.»—On the piece to be enameled apply oil varnish or white lead, and add a powder giving brilliant reflections, such as diamantine, brilliantine, or argentine. Dry in a stove. Apply a new coat of varnish. Apply the powder again, and finally heat in the oven. Afterwards, apply several layers of varnish; dry each layer in the oven. Apply pumice stone in powder or tripoli, and finally apply a layer of Swedish varnish, drying in the oven. This enamel does not crack. It adheres perfectly, and is advantageous for the pieces of cycles and other mobiles.

«Cold Enameling.»—This style of enameling is generally employed for repairing purposes. The various colors are either prepared with copal varnish and a little oil of turpentine, or else they are melted together with mastic and a trifle of oil of spike. In using the former, the surface usually settles down on drying, and ordinarily the latter is preferred, which is run on the cracked-off spot by warming the article. After the cooling, file the cold enamel off uniformly, and restore the gloss by quickly drawing it through the flame. For black cold enamel melt mastic together with lampblack, which is easily obtained by causing the flame of a wick dipped into linseed oil to touch a piece of tin.

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.»—Two different enamels are usually employed, viz., one for the ground and one for the top, the latter being somewhat harder than the former. Ground enamel is prepared by melting in an enameled iron kettle 625 parts brown shellac, 125 parts French oil of turpentine, with 80 parts colophony, and warming in another vessel 4,500 parts of spirit (90 per cent). As soon as the rosins are melted, remove the pot from the fire and add the spirit in portions of 250 parts at a time, seeing to it that the spirit added is completely combined with the rosins by stirring before adding any more. When all the spirit is added, warm the whole again for several minutes on the water bath (free fire should {722} be avoided, on account of danger of fire), and allow to settle. If a yellow color is desired, add yellow ocher, in which case the mixture may also be used as floor varnish.

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.»—Various methods are practiced in finishing furniture in white enamel, and while numerous preparations intended for the purpose named are generally purchasable of local dealers in paint supplies, it is often really difficult, and frequently impossible, to obtain a first-class ready-made enamel. To prepare such an article take 1⁠/⁠2 pint of white lead and add to it 1⁠/⁠4 pint of pure turpentine, 1⁠/⁠4 gill of pale coach Japan, and 1⁠/⁠2 gill of white dammar varnish. Mix all the ingredients together thoroughly. Apply with a camel’s-hair brush, and for large surfaces use a 2-inch double thick brush. There should be at least three coats for good work, applied after an interval of 24 hours between coats; and for strictly high-class work four coats will be necessary. Each coat should be put on thin and entirely free from brush marks, sandpapering being carefully done upon each coat of pigment. Work that has been already painted or varnished needs to be cut down with, say, No. 1⁠/⁠2 sandpaper, and then smoothed fine with No. 1⁠/⁠2 paper. Then thin white lead to a free working consistency with turpentine, retaining only a weak binder of oil in the pigment, and apply two coats of it to the surface. Give each coat plenty of time to harden (36 hours should suffice), after which sandpapering with No. 1 1⁠/⁠2 paper had best be done. Ordinarily, upon two coats of white lead, the enamel finish, as above detailed, may be successfully produced. For the fine, rich enamel finish adapted to rare specimens of furniture and developed in the mansions of the multimillionaires, a more elaborate and complex process becomes necessary.

«Quick-Drying Enamel Colors.»—Enamel colors which dry quickly, but remain elastic so that applied on tin they will stand stamping without cracking off, can be produced as follows:

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.»—So-called French varnish is made by dissolving I part of bleached or orange shellac in 5 parts of alcohol, the solution being allowed to stand and the clear portion then being decanted. The varnish may be colored by materials which are soluble in alcohol.

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.»—I.—Dissolve 10 pounds of India rubber in a mixture of 10 pounds of turpentine and 20 pounds of petroleum by treating same on a water bath. When the solution is completed add 45 pounds of drying oil and 5 pounds of lampblack and mix thoroughly.

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.»—The first thing to be done when a vessel is to be japanned, is to free it from all grease and oil, by rubbing it with turpentine. Should the oil, however, be linseed, it may be allowed to remain on the vessel, which must in that case be put in an oven and heated till the oil becomes quite hard.

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.»—I.—An excellent varnish for leather can be made from the following recipe: Heat 400 pounds of boiled oil to 212° F., and add little by little 2 pounds of bichromate of potash, keeping the same temperature. The addition of the bichromate should take about 15 minutes. Raise to 310° F., and add gradually during 1 hour at that temperature, 40 pounds Prussian blue. Heat for 3 hours more, gradually raising to 482° to 572° F., with constant stirring. In the meantime, heat together at 392° F., for 1⁠/⁠2 an hour, 25 pounds linseed oil, 35 pounds copal, 75 pounds turpentine, and 7 pounds ceresine. Mix the two varnishes, and dilute, if necessary, when cold with turpentine. The varnish should require to be warmed for easy application with the brush.

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.»—The following is a process giving a special varnish for aluminum, but it may also be employed for other metals, giving a coating unalterable and indestructible by water or atmospheric influences: Dissolve, preferably in an enameled vessel, 10 parts, by weight, of gum lac in 30 parts of liquid ammonia. Heat on the water bath for about 1 hour and cool. The aluminum to be covered with this varnish is carefully cleaned in potash, and, having applied the varnish, the article is placed in a stove, where it is heated, during a certain time, at a suitable temperature (about 1062° F.).

«Brass Varnishes Imitating Gold.»—I.—An excellent gold varnish for brass objects, surgical or optical instruments, etc., is prepared as follows: Gum lac, in grains, pulverized, 30 parts; dragon’s blood, 1 part; red sanders wood, 1 part; pounded glass, 10 parts; strong alcohol, 600 parts; after sufficient maceration, filter. The powdered glass simply serves for accelerating the dissolving, by interposing between the particles of gum lac and opal.

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.