This section is from the book "A Practical Treatise On Friction, Lubrication, Fats And Oils", by Emil F. Dieterichs. Also available from Amazon: A practical treatise on friction, lubrication, fats and oils.
Bring into the kettle 100 parts linseed oil or 60 parts linseed oil and 40 parts cotton oil, together with 10 parts rosin, and heat. When the rosin is melted allow to cool to 175° F., and then add, whilst crutching, 100 parts caustic potash lye of 22° Be. mixed with 4 parts soda lye of 38° Be. When the mass after continuous crutching commences to combine, add at once a solution of 7 parts calcined potash in 21 parts water to prevent thickening. When a complete paste has been formed allow the kettle to stand covered for about one hour to effect thorough combination. Samples are then taken and they should be perfectly clear and short. Small corrections regarding fitting can always be made. When the soap shows the proper constitution it is allowed to cool to 175° F. and filled, a suitable filling consisting of 5 parts potato-flour stirred together with 30 parts potassium chloride solution of 13° Be. For fitting about 4 to 5 parts potash lye of 28 Be. are required.
Heat 190 lbs. linseed oil and 10 lbs. crude palm oil to 190° F. and crutch in 84 lbs. caustic soda lye of 50° Be. mixed with 126 lbs. water. Combination will take place after crutching for half an hour. Then crutch in 14 lbs. of calcined potash dissolved in 42 lbs. of water. The soap is now entirely clear and can be immediately filled with 100 lbs. potato-flour stirred together with 290 lbs. potash solution of 12° Be. and 100 lbs. potassium chloride solution of 13° Be. The filling, previous to crutching in, should be heated to 145° F. and the soap itself should not be hotter than 176° F. The soap is then fitted with potash lye of 28° Be'., about 80 lbs. of it being required for this purpose, until a sample upon the glass is again short and firm.
Glucose flour mixed to a paste with the assistance of heat, and thinned out with linseed oil; then mixed with water.
Rosin is obtained by distillation of the crude turpentine obtained from several species of pine and fir trees, especially the pine trees of the States of North and South Carolina and Georgia.
The crude turpentine-resin is distilled with water, and yields about one-fourth of spirits of turpentine, the remainder being the common rosin of commerce.
Rosin is a semi-transparent solid and brittle product of smooth and shining fracture, of a yellowish-brown, sometimes almost black, color. It has a somewhat acrid and bitter taste, and is insoluble in, and rather heavier than, water.
Rosin melts at about 275° F., and is completely liquid at 306° F. It is soluble in the fixed and in volatile oils. Rosin distilled by itself yields rosin oil.
The first distillate below 674° is the lighter, at a specific gravity of about .987, or 12° Baume, at 60° F., and that over 675° F. being the second and heavier oil at a specific gravity of about .981 to .985, or 12° Baume, 60° F. Rosin oil readily resinifies by absorption of oxygen, and is much used as an adulterant of linseed oil and in the manufacture of printer's inks. Rosin oil consists of sylvic and pinic acids. When distilled with superheated steam, rosin yields benzol and toluol.
Oil of turpentine is also obtained by distillation of the cones of the pine trees. Its specific gravity is about 0.953 at 60° F., or 25° Baume.
Pine tar is obtained by charring the wood of pine and other coniferous trees.
Deodorized rosin oil is that freed from the "spirits" by fractional distillation.
Rosin or pine oil (kidney oil) is a somewhat thickish fluid of a brownish-yellow color, aromatic, turpentine-like odor and taste. Its specific gravity is about 0.985 at 60° F., or 12° Baume. At that temperature it is about ten times thicker than water, becomes whitish turbid at about 16° below zero F., and solidifies at about 20° below zero F. It is a slow-drying, gummy oil.
Glycerin, also called the sweet spirit of the fatty oils and fats, is a trihydric alcohol, and is not found readily formed in the fatty matter. All fats and fatty oils are considered glycer-ides, that is, compounds of fatty acids with a weak base called glyceryle. By the process of hot saponification the stronger alkaline bases unite with the fatty acids to form soapy compounds, thereby separating and setting the weaker base, "glycerin," free, and from ten to twelve per cent of it is thus obtained. Glycerin is also obtained from fatty matter by the action of superheated steam.
Under cold treatment of fatty matter with alk-line bases, the latter unite with the fatty acids and form oleates, stearates and palmitates of soda or potassa, but no glycerin.
Glycerin is a water-white, viscid liquid. It has no odor, but a very sweet taste. It boils at 550° F., is not volatile at ordinary temperature, but will vaporize at 212° F. When mixed and boiled with water it readily absorbs water from the air, and will mix with water in all proportions. It is miscible with alcohol in all proportions, but is insoluble in petroleum and benzine. A mixture of nitric acid and sulphuric acid forms with it "nitro-glycerin," a most powerful explosive.