IVORY
(See also Bones, Shell, and Horn.)
To Color Ivory:
Red.—The article is placed for 24 hours in water, 1,000 parts of which carry 100 parts of vinegar (acetic acid, 6 per cent), and from 1 to 5 parts of aniline red. As soon as it acquires the desired color pour off the liquid, let the ivory dry, and polish with Vienna lime.
Black.—Wash the article first in potash or soda lye and then put into a neutral solution of silver nitrate. Drain off the liquid and lay in the direct sunshine.
Red-Purple.—Put the article in a weak solution of triple gold chloride and then into direct sunshine.
Red.—For a different shade of red (from the first given), place the article for a short time in water weakly acidified with nitric acid and then in a solution of cochineal in ammonia.
Yellow.—Leave for several hours in a solution of lead acetate, rinse and dry. When quite dry place in a solution of potassium chromate.
To Color Billiard Balls Red.—
Fiery Red.—Wash the article first in a solution of carbonate of soda, then plunge for a few seconds in a bath of equal parts of water and nitric acid. Remove, rinse in running water; then put in an alcoholic solution of fuchsine and let it remain until it is the required color.
Cherry Red.—Clean by washing in the sodium carbonate solution, rinse and lay in a 2 per cent solution of tin chloride, for a few moments, then boil in a solution of logwood. Finally lay in a solution of potassium carbonate until it assumes the desired color.
Pale Red.—Wash in soda solution, rinse and lay for 25 minutes in a 5 per cent solution of nitric acid, rinse, then lay for several minutes in a weak solution of tin chloride. Finally boil in the following solution: Carmine, 2 parts; sodium carbonate, 12 parts; water, 200 parts; acetic acid enough to saturate.
Brown.—Apply several coats of an ammoniacal solution of potassium permanganate. Similar results are obtained if the solution is diluted with vinegar, and the ivory article allowed to remain in the liquid for some time.
Etching On Ivory
Flexible Ivory.
Another softening fluid is prepared by mixing 1 ounce of spirit of niter with 5 ounces of water and steeping the ivory in the fluid for 4 or 5 days.
Hardened Ivory.
Imitation Ivory:
See also Casein and Plaster.
Manufacture of Compounds Imitating Ivory, Shell, etc.—Casein, as known, may act the part of an acid and combine with bases to form caseinates or caseates; among these compounds, caseinates of potash, of soda, and of ammonia are the only ones soluble in water; all the others are insoluble and may be readily prepared by double decomposition. Thus, for example, to obtain caseinate of alumina, it is sufficient to add to a solution of casein in caustic soda a solution of sulphate of alumina; an insoluble precipitate of casein, or caseinate of alumina, is instantly formed. This precipitate ought to be freed from the sulphate of soda (formed by double decomposition) by means of prolonged washing.
When pure, ordinary cellulose may be incorporated with it by this process, producing a new compound, cheaper than pure cellulose, although possessing the same properties, and capable of replacing it in all its applications. According to the results desired, in transparency, color, hardness, etc., the most suitable caseinate should be selected. Thus, if a translucent compound is to be obtained, the caseinate of alumina yields the best. If a white compound is desired, the caseinate of zinc or of magnesia should be chosen; and for colored products the caseinates of iron, copper, and nickel will give varied tints.
The process employed for the new products, with a base of celluloid and caseinate, is as follows: On one hand casein is dissolved in a solution of caustic soda (100 of water for 10 to 25 of soda), and this liquid is filtered, to separate the matters not dissolved and the impurities.
On the other hand, a salt (of the base of which the caseinate is desired) is dissolved, and the solution filtered. It is well not to operate on too concentrated a solution. The two solutions are mixed in a reservoir furnished with a mechanical stirrer, in order to obtain the insoluble caseinate precipitate in as finely divided a state as possible. This precipitate should be washed thoroughly so as to free it from the soda salt formed by double decomposition, but on account of its gummy or pasty state, this washing presents certain difficulties, and should be done carefully. After the washing it should be freed from the greater part of water contained by draining, followed by drying, or energetic pressing; then it is washed in alcohol, dried or pressed again, and is ready to be incorporated in the mass of the celluloid.
For the latter immersion and washing, it has been found that an addition of 1 to 5 per cent of borax is advantageous, for it renders the mass more plastic, and facilitates the operation of mixing. This may be conducted in a mixing apparatus; but, in practice, it is found preferable to effect it with a rolling mill, operated as follows:
The nitro-cellulose is introduced in the plastic state, and moistened with a solution of camphor in alcohol (40 to 50 parts of camphor in 50 to 70 parts of alcohol for 100 parts of nitro-cellulose) as it is practiced in celluloid factories.
This plastic mass of nitro-cellulose is placed in a rolling mill, the cylinders of which are slightly heated at the same time as the caseinate, prepared as above; then the whole mass is worked by the cylinders until the mixture of the two is perfectly homogeneous, and the final mass is sufficiently hard to be drawn out in leaves in the same way as practiced for pure celluloid. These leaves are placed in hydraulic presses, where they are compressed, first hot, then cold, and the block thus formed is afterwards cut into leaves of the thickness desired. These leaves are dried in an apparatus in the same way as ordinary celluloid. The product resembles celluloid, and has all its properties. At 195° to 215° F. it becomes quite plastic, and is easily molded. It may be sawed, filed, turned, and carved without difficulty, and takes on a superb polish. It burns less readily than celluloid, and its combustibility diminishes in proportion as the percentage of caseinate increases; finally, the cost price is less than that of celluloid, {430} and by using a large proportion of caseinate, products may be manufactured at an extremely low cost.
Ivory And Bone Bleaches.
If simply dirty, scrub with soap and tepid water, using an old tooth or nail brush for the purpose. Grease stains may be sometimes removed by applying a paste of chalk or whiting and benzol, covering the article so that the benzol may not dry too rapidly. Carbon disulphide (the purified article) may be used in place of benzol. When dry, rub off with a stiff brush. If not removed with the first application, repeat the process. Delicately carved articles that show a tendency to brittleness should be soaked for a short time in dilute phosphoric acid before any attempt to clean them is made. This renders the minuter portions almost ductile, and prevents their breaking under cleaning.
The large scratched brush should be treated as follows: If the scratches are deep, the surface may be carefully rubbed down to the depth of the scratch, using the finest emery cloth, until the depth is nearly reached, then substituting crocus cloth.
To restore the polish nothing is superior to the genuine German putz pomade, following by rubbing first with chamois and finishing off with soft old silk. The more “elbow grease” put into the rubbing the easier the task, as the heat generated by friction seems to lend a sort of ductility to the surface. To remove the yellow hue due to age, proceed as follows: Make a little tripod with wire, to hold the object a few inches above a little vessel containing lime chloride moistened with hydrochloric acid; put the object on the stand, cover the whole with a bell glass, and expose to direct sunlight. When bleached, remove and wash in a solution of sodium bicarbonate, rinse in clear water and dry.
Like mother-of-pearl, ivory is readily cleaned by dipping in a bath of oxygenized water or immersing for 15 minutes in spirits of turpentine, and subsequently exposing to the sun for 3 or 4 days. For a simple cleaning of smooth articles, wash them in hot water, in which there has been previously dissolved 100 parts (by weight) of bicarbonate of soda per 1,000 parts of water. To clean carved ivory make a paste of very fine, damp sawdust, and put on this the juice of 1 or 2 lemons, according to the article to be treated. Now apply a layer of this sawdust on the ivory, and when dry brush it off and rub the object with a chamois.
Ivory Tests.
Many years ago an article was introduced in the industrial world which in contradistinction to the genuine animal ivory, has its origin in the vegetable kingdom, being derived from the nut of a palm-like shrub called phytelephasmacrocarpa, whose fruit reaches the size of an apple. This fruit has a very white, exceedingly hard kernel which can be worked like ivory. A hundred of these fruits only costing about $1, their use offers great advantages. Worked on the lathe this ivory can be passed off as the genuine article, it being so much like it that it is often sold at the same price. It can also be colored just like genuine ivory.
To distinguish the two varieties of ivory, the following method may be employed: Concentrated sulphuric acid applied to vegetable ivory will cause a pink coloring in about 10 or 12 minutes, which can be removed again by washing with water. Applied on genuine ivory, this acid does not affect it in any manner.
IVORY BLACK: See Bone Black.
IVORY CEMENT: See Adhesives.
IVORY GILDING: See Plating.
IVORY POLISHES: See Polishes.
JAPAN BLACK: See Paints.
JAPANNING AND JAPAN TINNING: See Varnishes.
JASMINE MILK: See Cosmetics.
JELLY (FRUIT) EXTRACT: See Essences and Extracts.
JEWELERS’ CEMENTS: See Adhesives.
JEWELERS’ CLEANING PROCESSES: See Cleaning Preparations and Methods.