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Previous Next The best candle and soap tips online! TECHNICAL TREATISE ON SOAP AND CANDLES. THE FABRICATION OP SOAPS. 277 white, has no influence on the color of the soap, but it changes its consistency and renders it more soluble and lathering. PASTING. (Empaiage.) We suppose a saponification made with 2250 pounds of oil. For this quantity use a kettle of a capacity of from 1000 to 1250 gallons. Pour into the kettle from 175 to 200 gallons of caustic lye of soft soda at 8° to 10° B., which is heated. When the lye begins to boil, pour on the oil, and to facilitate its combination with the lye, stir the mixture all the time; the stirring may be continued for half an hour after the last portion of oil has been introduced. This being done, boil the mixture. The ebullition must be very gentle to prevent the formation of too much foam. If, notwithstanding this precaution, the mixture rises, the heat is to be slackened, then the ebullition becomes less rapid, the foam diminishes, and the mixture boils regularly; but it is essential to watch the operation, for in the state of dilatation the paste is in, it would soon boil over. A gentle ebullition has also for its object to facilitate the combination of the oil with the lye. It is known that the paste is quite homogeneous, when neither oil nor lye is seen at the surface. This result being obtained, pour into the kettle lyes at a higher degree than the first, at 12° to 15° B., for example. The quantity of lye to be added is not well determined, but from six to eight gallons may be added without inconvenience every half hour, to take the place of the evaporated water. A slight excess of weak lye in the pasting is not injurious, and has the only inconvenience of making the operation a little longer and more expensive; but as a compensation, the oil is better saponified, and more completely deprived of its coloring and mucilaginous matters, and the soap is finer and better. After a gentle ebullition of eight or ten hours, the paste becomes thicker, and more homogeneous. To finish, introduce 25 to 50 gallons of lye at 5° B., and after stirring for half an hour, stop off the heat, and proceed to the separation, or cutting of the pan. SEPARATION. {Relargage.) This operation is conducted in the same manner as indicated for marbled soap, that is, by pouring little by little into the kettle perfectly limpid lyes of coction, i. e., salted lyes at 20° to 25° B. During the introduction of the lye, a man stirs the mass all the time. It is known that the quantity of lye is sufficient, when the soap separates from the lye, and acquires a clotted appearance. The more concentrated the lye, the less the quantity to be used to effect the separation. The operation being finished, cover the kettle, let it rest five or six hours, and then draw off the exhausted lye. If not sufficiently pure in color, this cutting of the pan can be repeated, when proceed to the coction. CLEAR-BOILING, OR COCTION. 1. First Service of Lye.—To begin the operation, pour at first into the kettle from 125 to 150 gallons of soft lye, at 15° to 18° B., heat gently, and when the soap is very warm, stop off the heat. This done, the soap is briskly stirred for three-quarters of an hour or an hour. By stirring thus, the soap is brought into contact with the lye, and by combining with the alkali it acquires more consistency, at the same time that it is deprived of the larger portion of the foreign salts that it has absorbed during the saponification and sepa ration. Rendered purer by this first washing, the soap is more fit to combine with the concentrated lyes which bring it to the proper point to be purified. After a settling of a few hours the lye is drawn off. 2. Second Service of Lye.—For this second service, pour into the kettle 100 gallons of caustic and concentrated lye, at 22° to 25° B. Boil the mixture gently for eight or ten 278 TECHNICAL TREATISE ON SOAP AND CANDLES. THE FABRICATION OF SOAPS. 279 hours, adding every hour six gallons of pure lye to take the place of the evaporated water. During the ebullition, a very abundant foam is formed on the surface of the soap, but its development is moderated by slacking the heat or beating it down with the stirrers, when during the ebullition the soap is entirely granulated, and floats in the lye. By pressing it between the fingers, it is found to have more consistency, but it is yet greasy, because it is not yet completely saturated with alkali. To bring it to the state of saturation, the heat is stopped oft", .and the mixture left to settle for a few hours; then a third and last service of new lye is given. 3. Third Service of Lye.—For this service, use a new lye marking 28° or 30° 13. Pour into the kettle 110 gallons of the lye and then heat. After an ebullition of five or six hours, the grain of the soap is well developed, and when pressed between the fingers forms hard and dry scales. Continue the ebullition for a few hours, and when the soap is saturated, the foam which covered it disappears almost entirely, and that which is left is very light and white. If the oil used is of a good quality, the kettle emits an odor somewhat similar to that of the violet; the heat is stopped oft', and after resting for a few hours, the lye is drawn off. This lye, by being passed over a mixture of soda and lime half exhausted, becomes clear, limpid, and caustic, and may be used anew to separate the soap in a subsequent operation. When thus saturated, this soap contains only 16 per cent, of water, and is very alkaline and caustic. Its coloration is due to the use of crude sodas, and especially to the presence of the sulphurets of soda and iron, always existing in these sodas, which combine with the oxide of iron, also existing in them, and give rise to a sulphuret of iron which colors the soap. To refine it, it ia necessary to submit it to a last operation called fitting and by the French soapmakers liquidation. FITTING. To transform into a pure white soap the mass of soap which has a bluish-gray color, it has to be dissolved by degrees in weak lyes with the aid of heat. To begin, pour into the kettle from 125 to 150 gallons of soft lye at 8° to 10° B. and apply heat. When the soap is very warm, stir it briskly. Under the influence of the heat, of the lyes, and the stirring, the grain dilates, softens, and looks as if half melted in the lye. When in this state slacken the heat, and after a few hours' rest, draw oft' the lye. By this first operation, the paste begins to be deprived of the coloring matter and the excess of alkali it contains, but it is still caustic. To complete its refining, pour into the kettle from 50 to 60 gallons of soft lye at 5° or 6° B. and heat gently, stirring the paste all the time from the bottom to the surface. By agitation and heat, the paste becomes more and more fluid, and is yet separate from the lye. As its refining can take place only when completely liquefied, to obtain this result, add from time to time a few pailfuls of lye at 2° or 3° B., continuing the heat and the stirring. When it has become fluid, and the liquid, brought to the surface by the stirring, has a blackish color and is viscous, the operation is finished, because the coloration is due to the precipitation of the alumino-ferruginous soap—and the viscosity to the complete liquefaction of all the parts of the paste. When in this state, stop off the heat, cover the kettle and surround it with woollen blankets, so as to retain the heat as long as possible. By resting and the heat of the mixture, the metallic soap, i. e., iron oxide soap, and the excess of alkali precipitate to the bottom of the kettle, as well as the excess of weak lyes used in this operation. After a rest of 36 to 40 hours, uncover the kettle, and take off carefully the scum formed on the surface. Dip off the soap with large iron ladles into frames. When the black soap begins to appear, the operator must be careful not to 280 Previous Next
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