Or, for the same purpose, melt to gether 5 ounces of rosin, I ounce of beeswax, 1 ounce of red ocher, and / tablespoonful of gypsum.
Leather Cement. — Dissolve in a double boiler 1 ounce of pure isin glass in / pint of ale. Add 2 ounces of common glue and dissolve with gen tle heat. Stir in 1 ounce of boiled lin seed oil until well mixed. This mix ture will have the texture of India rubber. Bottle and cork tightly for future use. Dilute when required with fresh ale, and after shaving the sur faces of the leather apply hot with a brush to harness and other belts, bands, etc. Let stand in a vise or under pressure until it sets. This is waterproof and a very powerful ad hesive.
Or dissolve in a double boiler equal quantities of glue and isinglass in water. Bring to a boil and stir in pure tannin until the mixture assumes the appearance of white of egg. Shave the leather, rub the edges with sand paper to roughen them, and apply the cement while hot. It will make a stronger joint if the surface is first moistened with a solution of gallnuts. A joint made' of this cement will be as strong as any other part of the leather.
Or, to fasten leather and other fibrous material to metals, dissolve glue in hot vinegar and add one third by volume of hot white pine pitch.
Collodion Cement.—Collodion is a mixture of 1 ounce of gun cotton and 1 ounce of alcohol in about 1 pound of ether. When used as a ce ment or varnish to prevent rust or for other purposes, it easily cracks and peels. To prevent this, add to each 18 ounces of collodion 4 ounces of Venice turpentine and 2 ounces of castor oil.
Or, when using collodion for sur gical purposes to dress cuts, etc., add to the ordinary collodion one eighth its volume of glycerin. This makes a varnish which adheres to the skin, but is elastic, and hence does not crack or crease.
Coppersmith's Cement. — Thicken fresh beef blood with powdered quick lime. Mix only as required and ap ply at once, as it sets rapidly. This is suitable for mending copper boil ers, rivets, leaks in copper pipes, fau cets, and the like. It is both cheap and durable.
Acid-proof Cement. — Mix in a double boiler 1k pounds of rosin, 4 ounces of dry red ocher, 2 ounces of plaster of Paris, and 1 ounce of linseed oil. Dissolve with gentle heat. Mix and apply while warm. Use this for cementing troughs to hold acid. It will stand boiling sul phuric acid.
Parchment Glue.—Boil in a double boiler 1 pound of parchment in 6 quarts of water down to 1 quart. Strain through cheese cloth to remove the sediment, and with gentle heat evaporate the liquid slowly to the con sistency of glue. Bottle and cork
tightly for use. Use this for fine work with delicate white paper.
Peach-tree Gum.—The gum which exudes from peach trees, when dis solved in alcohol and thinned with water, is a suitable cement for mend ing broken glassware, and is a good substitute for gum arabic, senegal, and the like.
To Mend Glass and China. — To take off grease or varnish, wash the pieces in ammonia and water, or ap ply alcohol or ether to the edges to be joined, but take care not to smooth off irregularities, as the rougher the surface the better the cement will hold. When the pieces are numerous it is best to unite them one at a time and let that harden before another is added. Select a quick-drying cement, heat the pieces, apply a thin coating of the cement to both surfaces, no more than will be partially absorbed, and bring the edges together before the cement sets. Hold them firmly until it hardens. After all the pieces have been thus united, let the article stand for several days or weeks be fore using.
Glue for Gilding.—Cut up rabbit skins as fine as possible, and boil them in water until the liquor on cooling is a firm gelatinous mass. Dilute with water, bring to a boil, and strain through a wire sieve.
Dissolve 1 part of alum and 3 parts of sulphate of zinc in boiling water, pour into the clear mixture, stir the whole while hot, and strain into a mold until it cools and jells. The mass will now be thick enough to re move from the mold and dry in the open air or with gentle heat.
Colored Cement.—To make a col ored cement suitable for uniting col ored glass or china, mix soluble glass with fine chalk and stir in the desired coloring matter. This cement requires six or eight hours to set. The follow ing coloring matters are recommended for this purpose: For black, sifted sulphide of an timony. This can be burnished to a fine metallic luster.
For gray black, fine iron dust.
For gray, zinc dust. This is a suitable cement for zinc castings. It also adheres to metals, stone, or wood.
For bright green, carbonate of cop per.
For dark green, sesquioxide of chromium.
For blue, Thenard's blue. For yellow, litharge.
For bright red, cinnabar. For violet, red carmine.
Soluble glass with chalk alone makes a white cement.
Equal quantities of sulphide of an timony and iron dust with soluble glass, a black cement.
Equal quantities of zinc dust and iron, a dark-gray cement.
Soluble glass can be kept in liquid form if covered tightly to exclude the air. Hence it is better to mix these cements only when wanted, and to keep the materials at hand for use when required.