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Previous Next The best candle and soap tips online! becomes strongly heated and breaks with violence, the fatty mass floating above. This fault is remedied by weakening the lye with water, and constantly stirring the mass. The production of some soap causes a corresponding weakening of the lye as a consequence, and the process again proceeds in a regular way. 2. In a not sufficiently caustic lye. This is discerned when by testing the lye with acid it foams up very strongly. A gradual addition of caustic lye remedies this defect. 3. In too much lye. Here we may help ourselves by the addition of fat, or, still better, by an addition of scrap-soap. After the first quarter of the soda has united with the fat or becomes pasted, the second quarter is added, for which a strong lye 15° to 18° B. will best serve. 20 litres (5.29 gallons) of such a lye contain about 2 kilog. (4.40 lbs.) soda, so we must therefore to reach 52.5 kilog. (115.5 lbs.) lye take of this lye 26.25 x 20, that is 525 litres "(139 gallons) lye. All further operations are entirely the same as in the case of Marseilles soap. 'The soap must be run hot into the frames, and for the first two days be well covered with cloths. On the second day it is cut on the edges and pressed or stamped down, to avoid its becoming hollow in the centre by shrinking. The touch or alkali of the sub-lye is removed by boiling it in a sufficient quantity of oleic acid, which also absorbs the carbonate of soda. Instead of oleic acid another fat can be applied, but the fat in this case must be previously made pasty. This is done by means of a small portion of weak caustic lye. The cutting of the pan is now performed with the still caustic sub-lye and adding ad libitum so much fat and salt to it until all trace of a touch in the lye has vanished. The last boiling is kept and applied to the next boilirig of soap. Many manufacturers use rosin for the removal of the touch, that is, for regaining the soda contained in the sub-lye, which is entirely l-ational, because the rosin combines as well with the carbonate as with the caustic soda. The rosin soap is to be, as usual, separated from the salt (cutting up of the pan) and afterwards added to another soap boiled in fat. It is 284 TECHNICAL TREATISE ON SOAP AND CANDLES. THE FABRICATION OF SOAPS. 285 self-evident that every other soap may be thus treated whose 8ub-lye still shows traces of a touch or presence of alkali. PALM SOAP. In saponifying palm oil it is customary to mix it with other fats and oils, either in its natural state, or deprived of its strong yellow color which will remain unchanged in the soap and will stain linen and other fabrics. The process of decolorizing the oils has been fully described elsewhere. In England many of the soaps for domestic uses are made of this oil, though usually in combination with tallow, cocoa-nut oil, and rosin, while in other countries where the oil is not so abundant it is principally used for toilet soaps, but rarely by itself. A pure palm-oil soap we will take for example: To 1000 kilog. (2200 lbs.) pure palm oil 110 kilog. (242 lbs.) soda are needed; this first, stronger lye must therefore contain 55 kilog. (121 lbs.)soda; lye of 18° B. is used,and, whereas such a lyecon-tains in the litre 0.161 kilog. (0.35 lb.), we must for 55 kilog. (121 lbs.) soda take 342 litres (90.3 gallons) of lye. As soon as the fat combines with this lye, there should be added gradually 360 litres (95 gallons) of a 20° B. lye having a tolerably strong touch. Since the palm oil often contains a considerable quantity of free palmitic acid, a certain quantity of carbonate of soda may be applied at once, and when this becomes saturated with the palmitin, then the rest is to be saponified with pure caustic lye. This is, however, not the same as if a carbonated soda lye were to be used. In this case, the intention would not be fulfilled, since the free palmitic acid absorbs at first the soda, while the carbonate of soda remains uncombined. The soap having finished boiling is separated by culinary salt, boiled until all froth disappears, gently ground or fitted, and the soap is run hot into the frames, where it is well covered and left to stand. In this case too, the rims of the soap in the frames are cut on the second day, and the soap pushed together. Palm-oil soap is always hard and brittle, and to divest it Previous Next
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