Soap solution

“ The color mixture for the soap and second application is made from 1 lb. of lampblack and 6 lb. of yellow ocher, both in oil; the finish coat may be any color desired. When no paint is to be used on the canvas it may be waterproofed with a mixture made from soft soap dissolved in hot water, and a solution of iron sulphate added. Iron sulphate, or ferrous sulphate, is the green vitriol. The vitriol combines with the potash of the soap, and the iron oxide is precipitated with the fatty acid as insoluble iron soap. This precipitate is then washed, dried and mixed with linseed oil. ”

“ It is important to run off the mother liquor (ley) containing the excess of alkali, for when the soap is used it consumes the alum to neutralise it."
When the impurities and ley have been removed the soap is dissolved in water, and if, from imperfect boiling, a portion of the resin is found not to have been saponified, a small quantity of a strong solution of soda crystals is added to the water used for dissolving the soap.
Where starch is used for stiffening purposes, the soap is mixed with a quantity of starch paste in the proportion of 11⁄2 part of starch to 1 part of resin soap. ”

“ Potassium chloride and potassium silicate find a limited use for intermixing with soft soaps.
It will be readily understood that hard and fast rules cannot be laid down for "liquoring" soap, and the correct solution to be employed can only be ascertained by experiment and experience, but the above suggestions will prove useful as a guide towards good results. A smooth, firm soap of clear, bright, glossy appearance is what should be aimed at.
Filling.—Some low-grade soaps contain filling, which serves no useful purpose beyond the addition of weight. ”

“ Soda soaps are insoluble in concentrated caustic lyes, and, for the most part, in strong solutions of sodium chloride, hence the addition [Pg 3] of caustic soda or brine to a solution of soda soap causes the soap to separate out and rise to the surface. Addition of brine to a solution of potash soap, on the other hand, merely results in double decomposition, soda soap and potassium chloride being formed, thus:—
The solubility of the different soaps in salt solution varies very considerably. ”

“ Of the colors producing green directly the two tar colors, Victoria and brilliant green, are to be noted; these give a bright color, but fade rapidly; thereby the soap acquires an unsightly appearance. For opaque soap of the better grades, green ultramarine or chrome green are used. Gray and black are produced by lampblack. For brown, there is Bismarck brown among the aniline colors and umber among the earthy pigments.
Garment-cleaning Soap.—The following is excellent:
Dissolve the soap in the water and when it cools down somewhat, add to the solution the ammonia water. ”

“ Some of the mineral substances which occur in solution in potable waters communicate to the latter the quality of hardness. Hard water decomposes soap, and cannot be efficiently used for washing. The chief hardening ingredients are salts of lime and magnesia. In the decomposition of soap these salts form curdy and insoluble compounds containing the fatty acids of the soap and the lime and magnesia of the salts. ”

“ Rosin Soap As An Emulsifier.—The soap should be made by boiling gently for 2 hours, in an evaporating dish, a mixture of 1,800 grains rosin and 300 caustic soda with 20 fluidounces water. Upon cooling, the soap separates as a yellow mass, which is drained from the liquid, squeezed, then heated on a water bath until it is dry and friable. Fixed oils may be emulsified by adding 1 ounce {290} to a solution of 10 grains soap in 1 ounce water. Volatile oils require 10 grains rosin soap, 2 3/4 ounces water, and 2 drachms oil. Creosote requires double this amount of soap. ”

“ This very useful article is produced by a combination of tallow or oil with soda or potash; with soda, hard soap is formed; with potash, soft soap. The yellow soap of commerce has also an addition of resin or turpentine, and often palm oil, these give it its yellow color and peculiar smell; pure white soap is made by boiling a solution of soda with tallow or olive oil; ordinary soaps are generally made by mixing a solution of the soda of commerce, (carbonate of soda) with quick lime, this takes away the carbonic acid and makes the soda what is called “caustic;” ”

“ They are now planed, and subjected to the proper mechanical treatment for making cakes of any form. The soap is coloured with strong alcoholic solution of archil for the rose tint, and of turmeric for the deep yellow. Transparent soaps, however pleasing to the eye, are always of indifferent quality; they are never so detergent as ordinary soaps, and they eventually acquire a disagreeable smell.
SOAPSTONE; see Steatite.
SODA, Caustic soda (Hydrate de soude, Fr.; Aetznatron, Germ.) ; is an alkaline substance, used in chemical researches, in bleaching, and in the manufacture of soap. ”

“ If to the neutral solution an extra portion of acid is added, so that there is an excess of acid over base, the neutralization is overbalanced in the opposite direction, and the solution acquires acid characteristics.
Most acids and bases will eat and corrode and discolor, while neutral substances will not; it is for this reason that soap, a slightly alkaline substance, is the safest cleansing agent for laundry, bath, and general work. Good soaps, being carefully made, are so nearly neutral that they will not fade the [223] color out of clothing ”

“ From Castile soap (in powder) , 11 oz.; chloride of lime (dry and good) , 1 oz.; mix, beat them to a mass with rectified spirit, q. s.; (holding in solution) oil of verbena or of ginger grass, 1⁄4 oz.; lastly, form the mass into flat tablets, and wrap these in thin sheet gutta percha. A most excellent detergent and stimulant soap in various affections, admirably adapted for hospital use, and for removing stains from the skin and rendering it white. It is the most powerful known agent against infection from contagious diseases communicable by contact.
Soap, Cod-Liver Oil. Syn. ”

“ I have known cases where soap containing about 83 per cent. of water has been sold at the full market price. Some soaps also contain more alkali than is actually combined with the fatty acids of the soap, and that excess alkali is injurious in washing silks and scouring [Pg 60] wool, and is also not good for the skin. The presence of this free or excess alkali can be at once detected by rubbing a little phenolphthalein solution on to the freshly-cut surface of a piece of soap; if free alkali be present, a red colour will be produced. ”

“ The most likely theory yet advanced is that based on the emulsifying power of soap solutions. The fact that these will readily form emulsions with oils has long been known, and the detergent action of soap has frequently been attributed to it, the explanation given being that the alkali set free by the water emulsifies the fatty matter always adhering to dirt, and carries it away in suspension with the other impurities. ”

“ Through the acid properties of the fats, the oleine, stearine, margarine, etc., which they contain, combine with the alkali to produce the saponified compound.
Hard soap is made with soda; soft soap with potash. The more oleine in the fat, the softer the soap; the more stearine the harder. Rosin is also largely used, sometimes to the extent of one-third the weight of the soap. It increases its hardness, makes it dissolve easier in water and forms a more copious lather.
The Most Economical Soap. Soap may be two-thirds water and still remain solid. Even dry, hard soap contains 20 or 25 per cent. ”

“ Miscellaneous Soaps.—The so-called " floating soaps " are soaps made lighter than water either by inserting cork or a metallic plate so as to form an air space within the tablet. The more usual method is to take milling soap, neutralize it with sodium bicarbonate or a mixture of fatty acids, and, after perfuming, it is aerated by mixing the hot soap with air in a specially designed crutcher. Shaving soaps, which must obviously be free from alkali or any substance which irritates the skin, are characterized by readily forming a permanent lather. ”

“ Another way in which it has been suggested that soap acts as a cleanser is that the soap itself or the alkali set free by hydrolysis serves as a lubricant, making the dirt less adherent, and thus promoting its removal. ”

“ Unless a soap-ley be rendered caustic, or deprived of its fixed air, it can have no natural attraction for vegetable or animal subtsances, such as oil, tallow, or grease of any kind, so as to convert them into a soap. For the sole purpose, therefore, of extracting the fixed air from the leys, do soapmakers use quicklime. Depriving the mild alkali of its fixed air, renders it caustic, or of a burning, corroding quality, and of that peculiar nature that instantly attach themselves to all greasy substances, and converts them into soap. ”

“ Since the employment of poor soaps works so injuriously upon the skin, many persons never, or rarely ever, use soap, but wash the face in water alone, or with a little almond bran added. Their skins cannot bear the regular application of poor soap. ”

“ It is really a question to what use a soap is to be put, and at what price it may be sold. There is, of course, a difference in the appearance, form and color, and then there are soaps of special kinds, such as floating soaps, transparent soaps, liquid soaps, etc., yet in the ultimate sense they are closely allied, because they are all the same chemical compound, varying only in their being a potash or soda soap, and in the fatty acids which enter into combination with these alkalis. ”

“ Shaving Soaps and Creams are made either with soda or potash, of fine tallow or cocoanut oil, which has the property of making a strong lather. Mottled Soaps owe their variegations of color to the use of iron oxides. It is said that these cannot be effectively applied if the soap contains an excess of water, and that more skill is required to make good blue mottled soap than any other. The more any soap is worked over, or remelted, cooled, etc., the better it becomes. ”

“ Another operation in which soap is used, is that of milling or fulling, whereby the fabric is made to shrink and thus becomes more compact and closer in texture. The fabric is thoroughly cleansed, for which purpose the soap should be neutral and free from rosin and silicates, otherwise a harsh feeling or stickiness will be produced. Curd soaps or finely-fitted soaps made from tallow or bleached palm oil, with or without the addition of cocoa-nut oil, give the best results. All traces of soap must be carefully removed if the fabric is to be dyed. ”

“ In the factory the alkali is proportioned by weight, so that as little free alkali is left as possible. Such a soap is called “neutral.” Resin is added, in yellow laundry soaps, and is supposed to aid in forming suds. When there is an excess of resin, as in some cheap soaps, it is hard to rinse out and colors the clothes. Borax is sometimes added to soap, and is useful when the water is hard, but not necessary in soft water. Naphtha or some other petroleum oil in soap increases the cleansing property of soap, by dissolving fatty or greasy impurities. ”

“ The only thing which will render it easy of removal is soap, as by its action it softens the oily material and dislodges it from the skin. Soap has acquired an evil reputation which it certainly does not deserve, and if it disagrees it is either due to the fact of its being an inferior article, or else the skin itself must be at fault. The best soap to use is the white, not the mottled, Castile, as it is made from pure olive oil. By the proper and judicious use of soap the skin is kept soft and natural, and the complexion is maintained in the hue of health. ”

“ Whatever filling material is used, it is important that the appearance of the soap should not be materially altered.
Neutralising, Colouring and Perfuming.—The free caustic alkali in soap, intended for toilet or laundry purposes, is usually neutralised [Pg 66] during the cleansing, although some soap manufacturers prefer to accomplish this during the milling operation. Various materials have been recommended for the purpose, those in most general use being sodium bicarbonate, boric acid, cocoa-nut oil, stearic acid, and oleic acid. ”

“ Effects of Strong Soap on Fabrics. Soap must not be strong enough to injure fabrics or discharge colors, yet sufficiently powerful to render grease and dirt soluble, so that it may be washed away in water. Rosin soap hardens the fibers of wool, and alkalies, if used to excess, shrink woolen fabrics. 54Hard water, or that containing lime or magnesia, more or less decomposes soap, and it floats on the surface as a greasy scum. But if an oily film rises to the top of soft water, it shows that the fat in the soap is not all saponified. ”

“ Any earthy salt, such as chalk or gypsum, decomposes soap, and prevents its action as a detergent. Soap consists of an oily acid combined generally with soda. Now, when this is added to water containing [Pg 51] lime, that earth unites with the oily acid, forming an insoluble soap, of no use as a detergent; this insoluble lime-soap is the curd which appears in hard water during washing with soap. Hard water is of no use as a cleanser, until all the lime has been removed by uniting with the oily acid of the soap. ”