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Leather, Ink, and Miscellaneous: Blacking

BLACKING LEATHER Blacking for Leather. -The pigments chiefly used in making shoe and harness blackings are lampblack and ivory black. Logwood is sometimes used in liquid blackings, and indigo and Prussian blue are sometimes added in small quantities. Lampblack is finely powdered carbon, resulting from the imperfect combustion of gases from substances containing carbon, as gas tar, wood tar, petroleum, and soft resinous woods. These substances are burned in a fireplace having a long flue, connecting with a series of chambers in which lampblack is deposited according to its fineness. The last chamber receives on a cloth screen the finest black of all. Hence lampblack varies in quality according to its degree of fineness. Crude lampblack contains some oily, tarry, and resinous matters which prevents its mixing freely with water. Hence, in preparing blacking for leather, it is customary to add a small amount of oil of vitriol or other acid, which chars and destroys these foreign substances, leaving the lampblack nearly pure carbon.

Ivory Black, bone black, or animal charcoal is produced by burning bones in close vessels. Various gases are driven off, leaving about one half the weight of the original bones in solid form. This is crushed and sifted, producing bone black, which varies in quality according to the degree of fineness. Animal charcoal is a very powerful absorbent of gases and of various substances from solutions. Under the name "ivory black" it is much used as a pigment in the preparation of shoe and harness blackings on account of its property of absorbing other substances, and thus producing a smooth and uniform mixture. It is somewhat more expensive than lampblack, to which it is usually preferred. Paste Blacking consists of a mixture of these pigments with molasses or sugar and various animal oils and fats or vegetable oils, more or less diluted with water, spirits, or vinegar, and with the addition of sulphuric acid or hydrochloric acid, or a mixture of these. The ordinary liquid blackings known as French polishes consist of the same pigments, with the addition of small quantities of gums or gelatin diluted with water, spirits, vinegar, or turpentine. Another class of liquid blackings, however, is formed of logwood, with the addition of small quantities of indigo or Prussian blue.

Paste Blacking. Mix with gentle heat 1 pound of ivory black, 8 ounces of molasses, and 2 ounces of sweet oil. Dissolve separately 2 ounces of hydrochloric acid in 4 ounces of water, and 4 ounces of sulphuric acid in 8 ounces of water. Mix the solutions, and add the mixture in a thin stream to the other ingredients, stirring vigorously. This is the ordinary German paste blacking of commerce. Mix 4 ounces of ivory black with LEATHER, INK, AND MISCELLANEOUS 1 tablespoonful of alcohol. Stir in 1 fluid ounce of sweet oil and 1/2 pint of molasses. Add 1 ounce of hydrochloric acid and 1 ounce of sulphuric acid.

Or, to make large quantities for sale, mix 50 pounds of ivory black, 12 pounds of molasses, and 1 gallon of rape oil. Dilute 10 pounds of oil of vitriol with 1 gallon of water, add this solution to the other substances in a thin stream, mixing thoroughly with a wooden shovel, and when stirred cover tightly, and let stand 24 hours.

Or mix 4 ounces of ivory black, 3 ounces of brown sugar, 1 tablespoonful of sweet oil, and 1 pint of beer. Or mix 3 ounces of ivory black, 2 ounces of molasses, 1 ounce of sulphuric acid, 1 ounce of gum arabic dissolved in water, 1 tablespoonful of sweet oil, and pint of vinegar.

Or mix 2 ounces of sulphuric acid with 4 ounces of tannin oil. Let stand 48 hours. Add 5 ounces of molasses and 1 pound of ivory black.

This is a celebrated commercial article.

Or mix 8 ounces of ivory black and 8 ounces of molasses. Add ounce of powdered alum, 1 dram of turpentine, 1 ounce of sulphuric acid, and 2 ounces of raw linseed oil.

Liquid Blacking.-Mix 4 ounces of ivory black with 1 tablespoonful of alcohol. Add 1 fluid ounce of sweet oil and pint of molasses; mix, and add 1 ounce of hydrochloric acid and 1 ounce of sulphuric acid.