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Previous Next The best candle and soap tips online! of time to effect as minute a division of the molecules as possible in the characteristic form of an emulsion. For this purpose a temperature greater than 48.9° C. (120° F.) is not, required. Perutz affirms that the facts discovered by Mege Mouries have been successfully applied in soap making. "To every rational nanufacturer," he says, "it must be known that saponification is produced with greater ease when the fat is stirred for about an hour under a slight heat—about 60° C. (140° F.) —with the so-called combination lye, and suffered to remain undisturbed for one night." As this mixture never reaches the boiling point, it follows that the globular emulsive state must be produced and saponification expedited. With the view of improving this discovery, and shortening the time of boiling, Perutz proposes to add to the fat the whole quantity of lye necessary for the saponification, and then proceed according to Mege Mouries' plan, leaving the mixture quiet all night. Until now, soap boilers have not, at the beginning, added the entire quantity of lye required, because experience has shown that saponification is thereby rendered more difficult; but, on the other hand, it has also been ascertained that the saponification is more rapidly effected at a low temperature. Whether this process of fabricating soap, as Mege Mouries asserts, is essentially cheaper than the usual method, could only be decided by experiment on a large scale, but that, if we work only with pure materials, a very beautiful pure soap is obtained, we have satisfied ourselves by experiments. Methods of M. D'Areet.—These suggestions have an interest here as they throw some light on our subject and have a scientific basis, and may be a guide to new methods. He remarks, there are two very distinct operations in the fabrication of eoaps; the first has for its object to chemically combine the alkali with the fatty bodies, while in the second, the formed eoap must be made to contain the proper quantity of water, by the processes of liquefaction or mottling if a white soap containing 50 per cent, of water, or a marbled soup containing only 33 per cent, is to be manufactured. 342 TECHNICAL TREATISE ON SOAP AND CANDLES. NEW SOAPS BY NEW METHODS. 343 The first operation, called eaponification, presents numerous difficulties; it is important to add to the fatty body the necessary caustic lye, little by little, and of a proper density, so that the soap when formed will not dissolve in the liquor, nor be transformed into too large and too hard grains. If the soap dissolves in the boiling lye, the whole will soon form a mass, the soap will burn at the bottom of the kettle, and the operation thus conducted will be impossible. If, on the contrary, the saponitication is effected by using too much of, or too concentrated a lye, the ebullition Avill with difficulty bring about a sufficient contact between the fatty bodies and the lye, which will retard the saponification, and increase the expense in fuel, work, etc. The necessity of keeping the soap during all the time of the saponification in a state of half solution in the boiling lye, presents great difficulties of execution, and renders the operation much longer and too costly. The saponification being finished, the soap is boiled down," that is, until the lye on which the soap floats is concentrated by evaporation to the density at which the grain contains just the necessary quantity of water. It is thus, that after the saponification, the soap contains more than 50 per cent, of water, while towards the end of the coction the grain of soap contains only about 16 per cent. This operation has for its principal object to leave in the grain of the soap only the proper quantity of lye, but it presents at the same time the advantage of completing the saponification, if this first operation has not already been completely effected, and besides, of rendering the soap homogeneous in all its parts. After the coction of the soap comes its liquefaction, if it is to be converted into white, or its mottling, if it is to be manufactured into marbled soap. The liquefaction or fitting has for its object to soften the grain of the soap, to introduce into it as much as 55 per cent, of water, instead of the 16 per cent, that the coction has left in it, to render the paste nearly liquid, and to favor thus, during the cooling of the soap in the frame, the precipitation of all foreign substances that the grains may contain, which contributes to bleach this kind of soap, and to give it much homogeneity, and a great degree of purity. As for the marbling of the soap, it might be improved. It is true that soap has been marbled at Marseilles for many, years, and when the art of soap-making is well understood it strikes me that since the origin of the art, the manufacturers have obtained soaps more or less well marbled. At the time of the saponification, the iron which is held in solution in the lye of sulphuretted soda combines with the fatty bodies and the iron of the kettle, and forms a soap of iron, and the manufacturer is often obliged to add some green vitriol; on the other hand, the alumina and lime contained in the lyes are also converted into soaps of alumina and lime, and these three soaps dissolve in the nearly liquid mixture of oil and soap submitted to the saponification. Later, when the saponification is finished, and even at the end of the coction, the soaps of iron, lime, and alumina are so uniformly divided in the mass, that it may be said that they are in a state of true solution. They color it a grayish-blue in all its parts, if the lye on which the soap boils has not ceased to be sulphuretted; and the soap,suddenly cooled and cut into thin plates, looks then like damp slate. The soap, being finished and colored as we have just stated, is too dry on account of the high density of the boiling lyes on which it floats. It must be brought back to contain at the most 36 per cent, of water. This is done by the operation called mottling, which has for its object to swell and soften the grains of soap. (See Marseilles Soap.) When this is done, the mass of soap ought to be evenly penetrated with water throughout; the grains must be soft and voluminous,hardly separated from the warm lye on which they float, and the greater part of which is interposed between the grains of soap properly softened. The soap is then run into the frame, and the operation is finished. Let us see what takes place in the frame. If the soap is run into a thin dish, and if a portion of the soap, taken at the time it is run into the frame, is quickly cooled down, a soap uniformly colored blue like damp slate 344 Previous Next
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