The best paste is made of good flour, well boiled. Resin, etc., do more harm than good.
2. An excellent white paste may be made by dissolving 2 1/2 oz. gum arabic in 2 quarts hot water and thickening with wheat flour. To this is added a solution of alum and sugar of lead; the mixture is heated and stirred till about to boil, when it is allowed to cool.
3. Four parts, by weight, of glue are allowed to soften in 15 parts of cold water for some hours, and then moderately heated till the solution becomes quite clear. 65 parts of boiling water are now added with stirring. In another vessel 80 parts of starch paste are stirred up with 20 parts of cold water, so that a thin milky fluid is obtained without lumps, into this the boiling glue solution is poured, with constant stirring, and the whole is kept at the boiling temperature. After cooling, 10 drops of carbolic acid are added to the paste. This paste is of extraordinary adhesive power, and may be used for leather, paper, or cardboard with great success. It must be preserved in closed bottles to prevent evaporation of the water, and will, in this way, keep good for years.
4. Rice flour makes an excellent paste for fine paper work.
5. Gum tragacanth and water make an ever ready paste. A few drops of any kind of acid should be added to the water before putting in the gum, to prevent fermentation. This paste will not give that semi-transparent look to thin paper, that gum arabic sometimes gives, when used for mucilage.
Add plaster of paris to a strong solution of alum till the mixture is of the consistency of cream. It sets readily, and is said to unite glass, metal, porcelain, etc., quite firmly. It is probably suited for cases in which large rather than small surfaces are to be united.
Melt yellow beeswax with its weight of turpentine and color with finely powdered Venetian red. When cold it has the hardness of soap, but is easily softened and moulded with the fingers, and for sticking things together temporarily it is invaluable.
When finely-pulverized chalk is stirred into a solution of soluble glass of 30° B until the mixture is fine and plastic, a cement is obtained which will harden in between six and eight hours, possessing an extraordinary durability, and alike applicable for domestic and industrial purposes. If any of the following substances be employed besides chalk, differently-colored cements of the same general character are obtained: - 1. Finely pulverized or levigated stibnite (grey antimony, or black sulphide of antimony) will produce a dark cement, which, after burnishing with an agate, will present a metallic appearance. 2. Pulverized cast iron, a grey cement. 3. Zinc dust (so-called zinc grey), an exceedingly hard grey cement, which, after burnishing, will exhibit the white and brilliant appearance of metallic zinc. This cement may be employed with advantage in mending ornaments and vessels of zinc, sticking alike well to metals, stone, and wood. 4. Carbonate of copper, a bright green cement. 5. Sesquioxide of chromium, a dark green cement. 6. Thenard's bine (cobalt blue), a blue cement 7. Minium, an orange-colored cement. 8. Vermilion, splendid red cement. 9. Carmine red, a violet cement.