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Previous Next The best candle and soap tips online! TECHNICAL TREATISE ON SOAP AND CANDLES THE FABRICATION OF SOAPS. 269 The action of the culinary salt does not always succeed at once, even if it is applied in soluble form, although it may thus cause a somewhat quicker operation. The more diluted the lye is, the more culinary salt will be needed for separation. Then, when, in consequence of an increased boiling, a greater concentration of the lye has been produced a separation will ensue; for as has already been stated, the separation of the soap does not so much rest upon the absolute quantity of culinary salt to a given quantity of soap, as upon the insolubility of the latter in a lye containing culinary salt, of a certain concentration. The manner in which the soap boils, is likewise a criterion as to whether the separation is complete. If instead of a smooth, lustrous surface, which is furrowed into small sections and circles, larger and rough divisions are visible, which are broken by steam under formation of bubbles, whereby the soap begins to rise, it may be presumed that the separation of the soap is completed. Moreover, the sub-lye must on no account have a touch or caustic taste, nor will this occur if the operation has been correctly performed, because the oil on hand is in double the quantity that the alkali present can absorb for forming a neutral soap. But if there should despite all this be some unsaponified oil therein, then a mistake has been made, the cutting of the pan has been premature, and must now, after the soap has been again rendered into paste by adding water, again boil until all the alkali becomes bound, and the sub-lye assumes a sweetish-salt taste. A further addition of culinary salt is not needed, and the soap reseparates without this, when the sub-lye, by the evaporation of water is again so concentrated, that it will no longer dissolve any soap. After a complete separation having ensued, the soap must remain a few hours longer in the kettle, during which time, the lye settles on the bottom, and is then drawn out by means of the waste pipe, which is in the bottom of the kettle. Where such a pipe is not present, the removal of the sub-lye is by a portable pump, which has its barrel on the lower end, or the soap is ladled from off the sub-lye into the cooling vat, which stands close to the boil- ing kettle. The soap is now prepared for the third operation of the coction or Clear-boiling.—For this operation, after removal of the sub-lye, the necessary lye is added to the soap, or if this is still in the cooling vat, then it is placed in the kettle, adding the soap from the cooling vat to it, and heating the entire mass till it boils. Some manufacturers divide even the lye necessary for a perfect saponification, and boil the soap first with one-half of the same, and allow all the sub-lye thus produced—having imparted all its alkali—to flow out, whereupon the same operation is repeated with the other half. This may be suitable in those cases where a very impure fat is worked up, but whenever the fats are pure, such a custom is at least superfluous. It would be best, from the start, to pay more attention to a careful cleaning of the fat by remelting and depositing, a process which under all circumstances is much easier than a boiling upon the so-called second, third, and fourth waters. Pure fats may even be boiled and finished upon one water, so that the letting oft" of the sub-lye, or a repeated scooping of the soap into a cooling vat, becomes entirely superfluous. Only if dark colored fats are used, which in a great measure impart their color to the sub-lye, and partly also to the water which is contained in the soap, it may be necessary to boil in two or three waters. This of course is dependent on the color, which each withdrawn lye should show. During the clear-boiling, the soap should boil as tenaciously as possible, that is, it should slip off with difficulty, when a sample is taken out with a spatula. It must become almost pasty, and whenever this does not take place at once, after adding a new quantity of lye, then the mass must have so much water added thereto, till it again returns into a glue-like substance. In this state, the lye acts upon the not yet completely saponified mass, and the process of saponification takes place much faster. It may hardly be necessary to remark, that, even if by a too abundant addition of water, the soap has turned into a real paste, this fault may be easily remedied by the addition of a little more salt. The boiling 270 Previous Next
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