so on until the vat is empty. Taking the Glue from the Moulds. Twelve hours are generally required for the glue to conweather 24 hours In taking the mass geal, but in warm may be necessary. from the mould dip the blade of a large knife (Fig. 18) in cold water, and with it loosen the glue from the sides of the box, which must be done skilfully and quickly. The box is then emptied on a table and the glue quickly cut into pieces of desired shape and thickness with a copper knife dipped in water. When a few cuts have been made the knife is again dipped in water, in order to give to the pieces a smooth surface and prevent them from becoming full of cracks. The hand is now dipped into water, and the pieces of glue laid upon hurdles strung with cord similar to a net (Figs. 19, 19 a) which are then carried into the drying-room and placed upon frames provided with strips Fig. 20). set 2 to 3 inches apart (Fig. In the course of a few hours the glue upon the hurdle is turned. It is then allowed to dry gradually, and when nearly dry is strung upon cord by means of a needle, and dried completely in the air, and is then ready for the market. specific gravity for 6 to 12 hours, and then press out. To extract all the tannin, which is absolutely necessary for the gaining of glue, the waste must be again treated with soda lye. It is then thoroughly washed, placed in dilute acid for 24 hours; then, to neutralize the acid, in a weak solution of soda, and finally thoroughly washed with water, when it is ready to be worked into glue in the ordinary manner. Maclagan's Apparatus and Process for Manufacturing Glue and Gelatine. The apparatus is intended for the extraction of gelatine from bones by the aid of steam. Fig. 21 represents a side view of the apparatus, and Fig. 22 the | placed in the extracting vessel f, which ground-plan; a is the steam-boiler; b a is carefully luted, and steam at a presspipe conducting the steam to all parts ure of atmosphere then introduced. а of the steam for 2 hours the gelatine is drawn off through the cock on the bottom of the extracting pan, and after filtering is brought into the evaporating pan c. Second Operation. Some of the fluid in the box d is brought into the extracting pan f, steam is again introduced, and after 3 hours the gelatine is drawn off, filtered, and added to the first. of the apparatus; c pipes conducting | After exposing the bones to the action the steam to the box d, serving for extracting the fat from the bones, then to the evaporating pan e, and finally to the extracting pan; f, g are cocks for regulating the introduction of steam; h pedestal upon which the extracting pan can be revolved; i are valves for the escape of steam; k cocks through which the steam leaves the extracting vessel; another cock is placed beneath the extracting vessel, through which the liquid gelatine is drawn off; are serpentine pipes through which steam passes to bring the fluids in the box d Third Operation. All the gelatine obtained having been brought into the evaporating pan e, it is evaporated to the proper consistency and then treated in the same manner as glue. Glue for Books. Dissolve over a moderate fire 12 parts of glue in 8 of water, add 8 parts of shavings of white soap, and, when all are dissolved, 6 of powdered alum, stirring the mass constantly. The sheets of paper may be either dipped into this fluid or it is applied with a sponge. To Make Gelatine from Glue. Soak | some time. It possesses extraordinary 5 pounds of good glue for 2 days in 1 adhesive power. gallons of strong vinegar, with 1 ounce of which saturate 40 to 45 grains of potassium carbonate. Then pour off the vinegar and place the glue in a sieve suspended in a vat of cold water, and allow it to remain 12 hours to remove the acetates adhering to the glue, which is now clear as glass, with a yellow tint. Glue thus prepared gives, when poured upon glass plates, white sheets of gelatine. They are somewhat more brittle than those obtained from bone glue, but this difficulty is overcome by adding more or less glycerine, according to the season of the year. In this manner gelatine can be produced which binds better than that obtained from bones, and at less cost. Liquid Steam Glue. The Russian steam glue is prepared in the following manner: Soak 100 pounds of good glue in 12 to 14 gallons of water, and add 5 to 6 pounds of aqua-fortis. The peculiar white color of Russian glue is produced by mixing 6 pounds of finely-powdered sulphate of lead with the solution. Heller's Steam Glue consists of 100 parts of good glue, 200 of water, and 12 of aqua-fortis. Cold Liquid Glue. Dilute 2 to 2 parts of crude nitric acid with 40 to 50 of water. Soak in this 25 parts of glue for 24 hours and then heat the mixture until it is homogeneous. The quantity of acid used depends on the quality of the glue. All other receipts have given unsatisfactory results. To Prepare Excellent Glue which will hold in Water. Powder and dissolve 1 part of glue in 1 of thick linseed-oil varnish boiling hot, and mix thoroughly. In using it heat the 2 planed sides of the wood, apply the glue warm, and press the pieces together. Good Furniture Glue. Boil the desired quantity of glue with water. When sufficiently boiled pour it into a porcelain dish and rub with a pestle into a thick paste free from lumps. Then pour it into an earthen-ware dish, let it cool, and cut it into pieces of desired size. When it is to be used dissolve 2 parts of the prepared glue in 1 of ordinary whiskey diluted with 2 of water, and let it boil up once. The glue is now ready for use and can be kept for Glue Resisting Wet and Moisture. Soak any desired quantity of glue in clean water for 11 hours, then pour the water off and stir the glue into a paste. On the other hand, take part of the glue used of isinglass, cut it in small pieces, soak for 12 hours in ordinary whiskey, and then rub it into a paste. Place an earthen pot on the fire and put in gradually portions of the glue and of the isinglass; stir constantly, add a few drops of linseed-oil varnish, strain through a clean cloth, and put the glue in bottles for future use. New Liquid Glue. This glue, which can be used for joining together all imaginable articles, even porcelain, glass, mother-of-pearl, etc., is prepared as follows: Pour 8 parts of water over 3 of glue cut in small pieces, and let it stand for a few hours. Then add part of hydrochloric acid gas and part of sulphate of zinc, and expose the mixture to a temperature of 175° to 190° F. for 10 to 12 hours. The glue does not again congeal, and if necessary can be still further clarified by allowing it to settle and then filtering. Bone Glue is manufactured from bones comminuted to the size of peas, or from waste in the manufacture of bone flour. The material is first moistened with a solution of oxalic acid in water, then piled in heaps and left to itself, whereby spontaneous heating takes place. It is then steamed in a glue boiler, the manhole being left open during the process. When the ammoniacal combinations have been expelled the material is subjected to a pressure of 2 to 3 atmospheres, and boiling water pumped in from time to time in order to completely dissolve the gelatine. The concentrated solution of glue, containing from 25 to 30 per cent. of dry substance, is finally pressed into a wooden vat, where it can be further concentrated, if necessary, by heating a steam-pipe. The whole process re-water for 24 hours. The bags are then quires from 5 to 6 hours. shaken in running water until, on taking a sample from the bag and placing it upon the tongue, no acid or any other taste is perceived. The bone-dust is now brought into a boiler with a hermetically fitting cover and 200 parts of water added to every 150 parts of bone flour weighed before immersion. The Dupasquier's Process of Preparing Bone Glue as a Substitute for Isinglass. Selecting and Bleaching the Bones. Remove all decayed and spongy parts of the bones and boil the sound portions for 1 hour to remove the fleshy and foreign substances. Potash lye is added near the end of the boiling to effectually clean the bones of fat. This lye consists of 1 pound each of potash and lime to every 100 pounds of bones. After remaining in the lye for 2 hours the bones are placed in baskets and set in running water to wash off the potash and foreign substances. Comminuting the Bones. Remove the bones from the baskets, dry, and grind them in a power mill. The mill used by the inventor is 6 feet in diameter and driven by horse-power, a strong horse being able to crush 150 pounds of bones to the size of beans in an hour. But it is better to grind the bones in an ordinary flour-mill, as the smaller the particles are the better the acid acts upon them. Immersing the Comminuted Bones in Hydrochloric Acid. The bone-dust is divided into 2 parts by sifting in a cylinder sieve. One part will be impalpable powder, while the other will be about as coarse as snuff. The reason for this division of the bone flour is that experience has taught that less acid is required for the fine powder than for the coarse. The following are the proportions: For every 100 parts of fine powder take 25 of hydrochloric acid and 75 of water; for 100 parts of coarse powder 50 of hydrochloric acid and 75 of water. The process is as follows: Pour the mentioned proportion of water over the bone flour in a large vat of white wood, and stir with a wooden shovel until every particle of flour is thoroughly moistened. Let it stand for 1 hour, then add of the mentioned proportion of acid, and, in intervals of 1 hour, the other 3. Let the acid act for 12 hours, stirring the mixture every hour with wooden shovels. Then draw off the liquor which contains hydrochlorate of lime, free phosphoric acid, and a certain quantity of free hydrochloric acid. The residue is filled into bags of a loose material and placed in running Fig. 23. whole is now boiled until all gelatine is entirely dissolved, which may be recognized by the sediment on the bottom becoming pasty and containing no particles offering resistance to pressure with the finger. Fig. 23 represents the Fig. 24. form of boiler used for the operation. The liquor is then drawn off and filtered through a bag, the residue pressed out, and the liquor obtained thereby added | taken from the cloth and laid either in to the first. Bleaching. Pour the liquor into a tall barrel (Fig. 24) and introduce a very vigorous current of sulphurous gas produced by decomposing sulphuric acid by charcoal. By the action of this acid the dark color of the liquor is converted into a bluish-white resembling that of a solution of good isinglass. Let the liquor settle and then draw it off through a faucet placed 3 inches above the bottom of the barrel. Pouring the Gelatine into Moulds. The liquor is carried in wooden buckets to another room where the moulds are arranged. They are made of white pine, are 5 feet long and 13 feet wide, and stand in a horizontal position alongside each other upon a wooden frame. Around the edge they are provided with a rim 1 inches high. They are painted with a coat of drying oil and white lead. The liquor is poured inch deep in them. A gelatine of firm consistency is soon formed, which is lifted out with wooden knives and laid upon loosely-woven cloths stretched out in a room through which a strong current of air passes. It remains here for 6 to 10 days, when it is sufficiently dry to be packed. Isinglass (Fish Glue). Genuine isinglass is yellowish-white or grayish-yellow to brown, transparent, very tough and flexible, can be easily torn only in the direction of the grain, has no taste or odor, and when chewed it becomes sticky. A solution of 1 part of isinglass in 50 of warm water is colorless and cools to a jelly. It consists of: Animal glue Osmazome Water Insoluble particles of skin Acid and salts of soda, potash, and lime 1 70 per cent. 16 It is principally manufactured in Russia from the bladders of the sturgeon and other fishes belonging to the same family. The bladders, after being placed in hot water, are cut open, washed, and exposed to the air with the inner, silvery skin upward. This is then removed by rubbing, placed in moistened cloths, pressed, and then serpentine windings between 3 small blocks or placed together in sheets like a book and dried. Printers' Rollers from Glue and Glycerine. Let good cabinet-makers' glue stand with water until a jelly has been formed, heat this in a water-bath, and, when melted, add as much glycerine as glue, stir, and then heat carefully until the water is evaporated. The product is an elastic substance well adapted for printers' rollers, moulds for galvanoplastic purposes, etc. Another process is as follows: Clean waste of skins by soaking in water for several days, then cut them in small pieces and cover them with glycerine. Boil the whole for some time at 212° to 235° F. When all the waste is dissolved pour the solution into another vessel, and, when cold, pour into moulds. Birdlime is a thick, soft, tough, and sticky mass of a greenish color, has an unpleasant smell and bitter taste, melts easily on heating, and hardens when exposed in thin layers to the air. It is difficult to dissolve in spirit of wine, but easily in hot alcohol, oil of turpentine, and fat oils, and also somewhat in vinegar. The best quality is prepared from the inner green bark of the holly (Ilex aquifolium), which is boiled, then put in barrels, and submitted for 14 days to slight fermentation until it becomes sticky. Another process of preparing it is to mix the boiled bark with juice of mistletoe berries and burying it in the ground until fermented. The bark is then pulverized, boiled, and washed. Artificial birdlime is prepared by boiling and then igniting linseed oil, or boiling printing varnish until it is very tough and sticky. It is further prepared by dissolving cabinet-makers' glue in water and adding a concentrated solution of chloride of zinc. The mixture is very sticky, does not dry on exposure to the air, and has the advantage that it can be easily washed off the feathers of the birds. The following mixtures give a good fly glue: I. Melt together 6 parts of colophony, 4 of rapeseed oil, and 3 of rosin. II. Eight parts of rosin, 4 each of turpentine and rapeseed oil, and of honey. |