LEATHER

(See also Shoes.)

Artificial Leather.

Black Dye For Tanned Leather.

Boil this solution slowly and the blacking is done. When it has cooled and settled, pour through linen, thus obtaining a pure, good leather blacking.

Bronze Leather.

The color is applied and well worked in with a stiff brush, and the skins allowed to stand for a short time, sufficient to allow the dye to penetrate the pores, when it is fulled. As for the shade of the bronze, it may be made reddish, bluish, or brownish, according to taste.

For a reddish or brownish ground the skins are simply fulled in warm water, planished, fulled again, and then dyed. According to the color desired, the skins are treated with cotton blue and methyl violet R, whereupon the application of the bronze follows.

The bronze is dissolved in alcohol, and it is usual to take 200 parts, by weight, of bronze to 1,000 of alcohol. By means of this mixture the peculiar component parts of the bronze are dissolved. For a fundamental or thorough {448} solution a fortnight is required. All bronze mixtures are to be well shaken or agitated before using. Skins may be bronzed, however, without the use of the bronze colors, for it is well known that all the aniline dyes present a bronze appearance when highly concentrated, and this is particularly the case with the violet and red dyes. If, therefore, the violet be applied in very strong solutions, the effect will be much the same as when the regular bronze color is employed.

Bronze color on a brown ground is the most beautiful of all, and is used to the greatest advantage when it is desirable to cover up defects. Instead of warm clear water in such a case, use a decoction of logwood to which a small quantity of alum has been added, and thus, during the fulling, impart to the skins a proper basic tint, which may, by the application of a little violet or bronze color, be converted into a most brilliant bronze. By no means is it to be forgotten that too much coloring matter will never produce the desired results, for here, as with the other colors, too much will bring out a greenish tint, nor will the gloss turn out so beautiful and clear. Next rinse the skins well in clean water, and air them, after which they may be dried with artificial heat. Ordinary as well as damaged skins which are not suitable for chevreaux (kid) and which it is desirable to provide with a very high polish, in order the more readily to conceal the defects in the grain, and other imperfections, are, after the drying, coated with a mixture, compounded according to the following simple formula: Stir well 1 pint of ox blood and 1 pint of unboiled milk in 10 quarts of water, and with a soft sponge apply this to the surface of the skin. The blood has no damaging effect upon the color. Skins thus moistened must not be laid one upon another, but must be placed separately in a thoroughly well-warmed chamber to dry. When dry they are glossed, and may then be pressed into shagreen or pebbled. The thin light goatskins are worked into kid or chevreaux. Properly speaking, they are only imitation chevreaux (kid), for although they are truly goatskins, under the term chevreaux one understands only such skins as have been cured in alum and treated with albumen and flour.

After drying, these skins are drawn over the perching stick with the round knife, then glossed, stretched, glossed again, and finally vigorously brushed upon the flesh side with a stiff brush. The brushing should be done preferably by hand, for the brushing machines commonly pull the skins out of all shape. Brushing is intended only to give the flesh side more of a flaky appearance.

During the second glossing care must be taken that the pressure is light, for the object is merely to bring the skin back into its proper shape, lost in the stretching; the glossing proper should have been accomplished during the first operation.

Cracked Leather.

Dressings For Leather:

For Carriage Tops.

II.—Shabby dark leather will look like new if rubbed over with either linseed oil or the well-beaten white of an egg mixed with a little black ink. Polish with soft dusters until quite dry and glossy.

Polishes.

II.—Dissolve 2 pounds of borax in 4 gallons of water and add 5 pounds of shellac to the boiling liquid in portions, till all is dissolved. Then boil half an hour, and finally stir in 5 pounds of sugar, 2 1/2 pounds of glycerine, and 1 1/2 pounds of soluble nigrosin. When cold add 4 pounds of 95 per cent methylated spirit.

III.—Ox blood, fresh, clean  1,000 parts
Commercial glycerine  200 parts
Oil of turpentine  300 parts
Pine oil (rosin oil)5,000 parts
Ox gall  200 parts
Formalin   15 parts

Mix in the order named, stirring in each ingredient. When mixed strain through linen.

Kid Leather Dressings.

White Cream.—

Lard75 parts
Glycerine, technical25 parts
Mirbane oil, ad libitum.

Black Cream.—

Lard100 parts
Yellow vaseline 20 parts
Glycerine, technical 10 parts
Castor oil, technical 10 parts

Dye black with lampblack and perfume with oil of mirbane.

Colored Cream.—

Lard100 parts
Castor oil 20 parts
Yellow wax 25 parts
White vaseline 30 parts

Dye with any desired dyestuff, e. g., red with anchusine, green with chlorophyl. In summer it is well to add some wax to the first and second prescriptions.

These are for either Morocco or kid:

I.—Shellac  2 parts
Benzoin  2 parts
Yellow wax  5 parts
Soap liniment  7 parts
Alcohol600 parts

Digest until solution is effected, then allow the liquid to stand in a cool place for 12 hours and strain. Apply with a bit of sponge or soft rag; spread thinly and evenly over the surface, without rubbing much. If dirty, the leather should first be washed with a little soft soap and warm water, wiped well, and allowed to dry thoroughly before the dressing is put on.

II.—Oil of turpentine 8 ounces
Suet 2 pounds
Soft soap 8 ounces
Water16 ounces
Lampblack 4 ounces
Patent Leather Dressings.—
I.—Wax22 parts
Olive oil60 parts
Oil turpentine, best20 parts
Lavender oil10 parts

With gentle heat, melt the wax in the oil, and as soon as melted remove from the fire. Add the turpentine oil, incorporate, and when nearly cold, add and incorporate the lavender oil.

II.—Wax22 parts
Olive oil60 parts
Oil of turpentine30 parts

With gentle heat, melt the wax in the olive oil, and as soon as melted remove from the fire. When nearly cold stir in the turpentine.

Red Russia Leather Varnish.—
Shellac1.20 parts
Dammar rosin, powdered0.15 parts
Turpentine, Venice0.60 parts

Dissolve with frequent shaking in 12 parts of alcohol (95 per cent), add 1.8 parts of powdered red sanders wood, let stand for 3 days and filter. The object of this varnish is to restore the original color to worn Russia leather boots, previously cleaned with benzine.

Russet Leather Dressing.
I.—Soft soap2 parts
Linseed oil3 parts
Annatto solution (in oil)8 parts
Beeswax3 parts
Turpentine8 parts
Water8 parts

Dissolve the soap in the water, and add the annatto; melt the wax in the oil and turpentine, and gradually stir in the soap solution, stirring until cold. {450}

II.—Palm oil16 parts
Common soap48 parts
Oleic acid32 parts
Glycerine10 parts
Tannic acid 1 part

Melt the soap and palm oil together at a gentle heat, and add the oleic acid; dissolve the tannic acid in the glycerine, add to the hot soap and oil mixture, and stir until perfectly cold.

Shoe Leather Dressing.

Dyeing Leather.

In dyeing leather, aniline or coal-tar colors are generally used. These dyes, owing to their extremely rapid action on organic substances, such as leather, do not readily adapt themselves to the staining process, because a full brushful of dye liquor would give a much deeper coloration than a half-exhausted brush would give. Consequently, to alter and to color leather by the staining process results in a patchy coloration of the skin. In the dyeing operation a zinc shallow trough, 4 to 6 inches deep, is used, into which the dye liquor is put, and to produce the best results the contents of the trough are kept at a uniform temperature by means of a heating apparatus beneath the trough, such as a gas jet or two, which readily allows of a heat being regulated. The skins to be dyed are spread out flat in the dye trough, one at a time, each skin remaining in the dye liquor the time prescribed by the recipe. The best coloration of the skin is produced by using 3 dye troughs of the same dye liquor, each of different strength, the skin being put in the weakest liquor first, then passed into the second, and from there into the third dye liquor, where it is allowed to remain until its full depth of color is obtained. Very great skill is required in the employment of aniline dyes, as if the heat be too great, or the skins remain too long in the final bath, “bronzing” of the color occurs. The only remedy for this (and that not always effectual) is to sponge the skin with plenty of cold, clean water, directly it is taken out of the final dye bath. The dyed skins are dried and finished as before.

Leather Brown.—
Extract of fustic5 ounces
Extract of hypernic1 ounce
Extract of logwood  1/2 ounce
Water2 gallons

Boil all these ingredients for 15 minutes, and then dilute with water to make 10 gallons of dye liquor. Use the dye liquor at a temperature of 110° F.

Mordant.—Dissolve 3 ounces of white tartar and 4 ounces of alum in 10 gallons of water.

Fast Brown.
Bismarck Brown.—
Extract of fustic4 ounces
Extract of hypernic1 ounce
Extract of logwood  1/2 ounce
Water2 gallons

Preparation.—Boil all together for 15 minutes.

Method of Dyeing.—First mordant the skins with a mordanting fluid made by dissolving 3 ounces tartar and 1/2 ounce borax in 10 gallons of water. Then put the skins into the above foundation bath at a temperature of 100° F. Take them out, and then put in 1 ounce of Bismarck brown, dissolved in boiling water. Put the skins in again until colored deep enough, then lift out, drip and dry.

Harness Preparations:

Blacking For Harness.

II.—Best glue, 4 ounces; good vinegar, 1 1/2 pints; best gum arabic, 2 ounces; good black ink, 1/2 pint; best isinglass, 2 drachms. Dissolve the gum in the ink, and melt the isinglass in another vessel in as much hot water as will cover it. Having first steeped the glue in the vinegar until soft, dissolve it completely by the aid of heat, stirring to prevent burning. The heat should not exceed 180° F. Add the gum and ink, and allow the mixture to rise again to the same temperature. Lastly mix the solution in isinglass, and remove from fire. When {451} used, a small portion must be heated until fluid, and then applied with a sponge and allowed to dry on.

Dressings For Harness.—
I.—Ox blood, fresh and well purified100 parts
Glycerine, technical 20 parts
Turpentine oil 30 parts
Pine oil 50 parts
Ox gall 20 parts
Formalin  1 1/2 parts

The raw materials are stirred together cold in the order named. Pour the mixture through thin linen. It imparts a wonderful mild, permanent gloss.

II.—A French harness dressing of good quality consists of oil of turpentine, 900 parts; yellow wax, 90 parts; Berlin blue, 10 parts; indigo, 5 parts; and bone black, 50 parts. Dissolve the yellow wax in the oil of turpentine with the aid of moderate heat in a water bath, mix the remaining substances, which should previously be well pulverized, and work them with a small portion of the wax solution. Finally, add the rest of the wax solution, and mix the whole well in the water bath. When a homogeneous liquid has resulted, pour it into earthen receptacles.

Harness Oils.—
I.—Neatsfoot oil10 ounces
Oil of turpentine 2 ounces
Petrolatum 4 ounces
Lampblack   1/2 ounce

Mix the lampblack with the turpentine and the neatsfoot oil, melt the petrolatum and mix by shaking together.

II.—Black aniline 35 grains
Muriatic acid 50 minims
Bone black175 grains
Lampblack 18 grains
Yellow wax  2 1/2 av. ounces
Oil of turpentine 22 fluidounces
III.—Oil of turpentine  8 fluidounces
Yellow wax  2 av. ounces
Prussian blue    1/2 av. ounce
Lampblack    1/4 av. ounce

Melt the wax, add the turpentine, a portion first to the finely powdered Prussian blue and lampblack, and thin with neatsfoot oil.

Harness Pastes.—
I.—Ceresine, natural yellow1.5 parts
Yellow beeswax1.5 parts
Japan wax1.5 parts

Melt on the water bath, and when half cooled stir in 8 parts of turpentine oil.

Harness Grease.—
By weight
II.—Ceresine, natural yellow2.5 parts
Beeswax, yellow0.8 parts
French colophony, pale0.4 parts
III.—French oil turpentine2.0 parts
Intimately mixed in the cold with American lampblack1.5 parts

Put mixture I in a kettle and melt over a fire. Remove from the fire and stir in mixture II in small portions. Then pour through a fine sieve into a second vessel, and continue pouring from one kettle into the other until the mass is rather thickish. Next fill in cans.

Should the mixture have become too cold during the filling of the cans, the vessel containing the grease need only be placed in hot water, whereby the contents are rendered liquid again, so that pouring out is practicable. For perfuming, use cinnamon oil as required.

This harness grease is applied by means of a rag and brushed.

Waterproof Harness Composition.—

See also Waterproofing.

By weight
Rosin spirit27 1/4 parts
Dark mineral oil13 1/2 parts
Paraffine scales16.380 parts
Lampblack 7.940 parts
Dark rosin 5.450 parts
Dark syrup 5.450 parts
Naphthalene black 2.500 parts
Berlin blue 0.680 parts
Mirbane oil 0.170 parts

Melt the paraffine and the rosin, add the mineral oil and the rosin spirit, stir the syrup and the pigments into this, and lastly add the mirbane oil.

Patent And Enameled Leather.

Patent leather for boots and shoes is prepared from sealskins, enameled leather for harness from heavy bullock’s hides. The process of tanning is what is called “union tannage” (a mixture of oak and hemlock barks). These tanned skins are subjected to the process of soaking, unhairing, liming, etc., and are then subjected to the tanning process. When about one-third tanned a buffing is taken off (if the hides are heavy), and the hide is split into three layers. The top or grain side is reserved for enameling in fancy colors for use on tops of carriages; the middle layer is finished for splatter {452} boards and carriage trimmings, and some parts of harness; the underneath layer, or flesh side is used for shoe uppers and other purposes. The tanning of the splits is completed by subjecting them to a gambier liquor instead of a bark liquor.

When the splits are fully tanned they are laid on a table and scored, and then stretched in frames and dried, after which each one is covered on one side with the following compound, so as to close the pores of the leather that it may present a suitable surface for receiving the varnish: Into 14 parts of raw linseed oil put 1 part dry white lead and 1 part silver litharge, and boil, stirring constantly until the compound is thick enough to dry in 15 or 20 minutes (when spread on a sheet of iron or china) into a tough, elastic mass, like caoutchouc. This compound is laid on one side of the leather while it is still stretched in the frame. If for enameled leather (i. e., not the best patent), chalk or yellow ocher may be mixed in the above compound while boiling, or afterwards, but before spreading it on the leather.

The frames are then put into a rack in a drying closet, and the coated leather dried by steam heat at 80° to 160° F., the heat being raised gradually. After removal from the drying closet, the grounding coat previously laid on is pumiced, to smooth out the surface, and then given 2 or 3 coats of the enameling varnish, which consists of Prussian blue and lampblack boiled with linseed oil and diluted with turpentine, so as to enable it to flow evenly over the surface of the coated leather. When spread on with a brush, each coating of the enamel is dried before applying the next, and pumiced or rubbed with tripoli powder on a piece of flannel (the coat last laid on is not subjected to this rubbing), when the leather is ready for market.

To prepare the enameling composition, boil 1 part asphaltum with 20 parts raw linseed oil until thoroughly combined; then add 10 parts thick copal varnish, and when this mixture is homogeneous dilute with 20 parts spirit of turpentine.

Instead of the foregoing enameling varnish the following is used for superior articles:

Prussian blue 18 ounces
Vegetable black  4 ounces
Raw linseed oil160 fluidounces

Boil together as previously directed, and dilute with turpentine as occasion requires. These enameling varnishes should be made and kept several weeks in the same room as the varnishing is carried on, so that they are always subjected to the same temperature.

Stains For Patent Leather:

Black Stain.—
Vinegar 1 gallon
Ivory black14 ounces
Ground iron scales 6 pounds

Mix well and allow to stand a few days.

Red Stain.
Liquid Cochineal Stain.—
Good French carmine2 1/2 drachms
Solution of potash  1/2 ounce
Rectified spirit of wine2 ounces
Pure glycerine4 ounces
Distilled water to make1 pint.

To the carmine in a 20-ounce bottle add 14 ounces of distilled water. Then gradually introduce solution of potash, shaking now and again until dissolved. Add glycerine and spirit of wine, making up to 20 ounces with distilled water, and filter.

Blue Black.
Finishers’ Ink.

Grind the gum and potassium bichromate to powder and then add all the coloring ingredients to the water and boil.

To Restore Patent Leather Dash.

Preservatives For Leather.

I.—Mutton suet50 parts
Sweet oil50 parts
Turpentine 1 part
Melt together.

The application should be made on the dry leather warmed to the point where it will liquefy and absorb the fat.

II.—Equal parts of mutton fat and linseed oil, mixed with one-tenth their {453} weight of Venice turpentine, and melted together in an earthen pipkin, will produce a “dubbin” which is very efficacious in preserving leather when exposed to wet or snow, etc. The mixture should be applied when the leather is quite dry and warm.

III.—A solution of 1 ounce of solid paraffine in 1 pint light naphtha, to which 6 drops of sweet oil have been added, is put cold on the soles, until they will absorb no more. One dressing will do for the uppers. This process is claimed to vastly increase the tensile strength.

Patent Leather Preserver.—
Carnauba wax1.0 part
Turpentine oil9.5 parts
Aniline black, soluble in fat0.06 parts

Melt the wax, stir in the turpentine oil and the dye and scent with a little mirbane oil or lavender oil. The paste is rubbed out on the patent leather by means of a soft rag, and when dry should be polished with a soft brush.

Revivers And Regenerators.

By weight.
I.—Methylic alcohol22 1/2 parts
Ground ruby shellac 2.250 parts
Dark rosin 0.910 parts
Gum rosin 0.115 parts
Sandarac 0.115 parts
Lampblack 0.115 parts
Aniline black, spirit-soluble 0.115 parts

The gums are dissolved in spirit and next the aniline black soluble in spirit is added; the lampblack is ground with a little liquid to a paste, which is added to the whole, and filtering follows.

Kid Reviver.—

By weight.
II.—Clear chloride of lime solution3.5 parts
Spirit of sal ammoniac0.5 parts
Scraped Marseilles soap4.5 parts
Water6.0 parts

Mix chloride of lime solution and spirit of sal ammoniac and stir in the soap dissolved in water. Revive the gloves with the pulpy mass obtained, by means of a flannel rag.

Tanning Leather.

Pickling Process.

The goods pickled with the largest amount of acid possessed a more leathery feel and after drying were fuller and stretched much better than those in which smaller amounts of acids were employed. Dried, pickled pieces, containing as much as 3 per cent of sulphuric acid, showed no deterioration or tendering of fiber. The pickled skins after chrome tanning still retained these characteristics. An analysis of the leather produced by tanning with sumac showed that no free acid was retained in the finished leather. An Australian pickled pelt was found to contain 19.2 per cent of salt and 2.8 per cent of sulphuric acid.

From a very large number of experiments the following conclusions were drawn: 1. That sulphuric acid is quite equal in efficiency to other acids for the purpose. 2. To a certain limit increasing softness is produced by increasing the quantity of acid used. 3. For naturally soft skins and when a leather not very soft is required the best results are obtained by using 22 pounds of salt, 2.2 pounds of sulphuric acid, and 25 gallons of water for 110 pounds of pelt in the drum. 4. For material which is naturally hard and when a soft leather is required, the amount of acid should be increased to 4.4 pounds, using similar amounts as those given above of pelt, salt, and water.

French Hide Tanning Process.

II.—The hides are soaked in a solution of sodium carbonate of 10° Bé. for 3 to 6 hours. After washing with water they are allowed to remain for 5 hours in {454} a bath of caustic soda, the strength of which may vary from 2° to 30° Bé. From this they are transferred to a bath of hydrochloric acid (1° to 5° Bé.) in which they remain for 2 hours. Finally the hides are washed and the beam-work finished in the usual way. The tannage consists of a special bath of sodium or ammonium sulphoricinoleate (2 to 30 per cent) and sumac extract, or similar tanning material (2 to 50 per cent). The strength of this bath is gradually raised from 4° to 30° or 40° Bé.

Tanning Hides For Robes.
Lace Leather.

For stuffing, use 3 gallons curriers’ hard grease and 3 gallons American cod oil. Strike out from mill, on flesh. Set out on grain. Dry slowly. Trim and board, length and cross. The stock is then ready to cut. The time for soaking the hides may be reduced one-half by putting the stock into a rapidly revolving reel pit, with a good inflow of water, so that the dirty water washes over and runs off. After 10 hours in the soak, put the stock into a drum, and keep it tumbling 5 hours. This produces soft stock.

In liming, where the saving of the hair is no object, softer leather is obtainable by using 35 pounds sulphide of sodium with 60 pounds lime. Then, when the stock comes from the limes, the hair is dissolved and immediately washes off, and saves the labor of unhairing and caring for the hair, which in some cases does not pay.

Miscellaneous Recipes:

Russian Leather.

The hides are steeped in this compound for 2 days, until swelled up, and then put into a solution of willow and poplar barks, in which they are allowed to remain 8 days, being frequently turned about. The tanning process is then completed by putting them into a tanning liquor composed of pine and willow barks, equal parts. They are steeped 8 days in this liquor, and then a {455} fresh liquor of the same ingredients and proportions is made up. The hides are hardened and split, and then steeped in the freshly made liquor for another 8 days, when they are sufficiently tanned.

The hides are then cut down the middle (from head to tail) into sides, and scoured, rinsed, and dried by dripping, and then passed on to the currier, who slightly dampens the dry sides and puts them in a heap or folds them together for a couple of days to temper, and then impregnates them with a compound consisting of 2/3 parts birch oil and 1/3 parts seal oil. This is applied on the flesh side for light leather, and on the grain side also for heavy leather. The leather is then “set out,” “whitened,” and well boarded and dried before dyeing.

A decoction of sandalwood, alone or mixed with cochineal, is used for producing the Russian red color, and this dye liquor is applied several times, allowing each application to dry before applying the following one. A brush is used, and the dye liquor is spread on the grain side. A solution of tin chloride is used in Russia as a mordant for the leather before laying on the dye. The dye liquor is prepared by boiling 18 ounces of sandalwood in 13 pints of water for 1 hour, and then filtering the liquid and dissolving in the filtering fluid 1 ounce of prepared tartar and soda, which is then given an hour’s boiling and set aside for a few days before use.

After dyeing, the leather is again impregnated with the mixture of birch and seal oils (applied to the grain side on a piece of flannel) and when the dyed leather has dried, a thin smear of gum-dragon mucilage is given to the dyed side to protect the color from fading, while the flesh side is smeared with bark-tan juice and the dyed leather then grained for market.

Toughening Leather.
Painting On Leather.

If such leather, so called kips, which are much used for carriage covers and knee caps, is to be prepared for painting purposes, it is above all necessary to close up the pores of the leather, so that the said fat particles cannot strike through. They would combine with the applied paint and prevent the latter from drying, as the grease consists mainly of fish oil. For this reason an elastic spirit leather varnish is employed, which protects the succeeding paint coat sufficiently from the fat.

For further treatment take a good coach varnish to which 1/4 of stand oil (linseed oil which has thickened by standing) has been added and allow the mixture to stand for a few days. With this varnish grind the desired colors, thinning them only with turpentine oil. Put on 2 coats. In this manner the most delicate colors may be applied to the leather, only it is needful to put on pale and delicate shades several times. In some countries the legs or tops of boots are painted yellow, red, green, or blue in this manner. Inferior leather, such as sheepskin and goat leather, which is treated with alum by the tanner, may likewise be provided with color in the manner stated. Subsequently it can be painted, gilded, or bronzed.

Stains For Oak Leather.

II.—The moistened leather is primed with a solution of 1 part, by weight, of copper acetate in 50 parts of water, slicked out and then painted with solution of yellow prussiate potash in feebly acid water.

LEATHER AS AN INSULATOR: See Insulation.

LEATHER CEMENTS: See Adhesives, under Cements.

LEATHER-CLEANING PROCESSES: See Cleaning Preparations and Methods.

LEATHER, GLUES FOR: See Adhesives.

LEATHER LAC: See Lacquers.

LEATHER LUBRICANTS: See Lubricants. {456}

LEATHER VARNISH: See Varnish.

LEATHER WATERPROOFING: See Waterproofing.