Tire Cements.—
| I.— | India rubber | 15 grams |
|---|---|---|
| Chloroform | 2 ounces | |
| Mastic | 1/2 ounce |
Mix the india rubber and chloroform together, and when dissolved, the mastic is added in powder. It is then allowed to stand a week or two before using.
II.—The following is recommended as very good for cementing pneumatic tires to bicycle wheels:
| Shellac | 1 ounce |
| Gutta percha | 1 ounce |
| Sulphur | 45 grains |
| Red lead | 45 grains |
Melt together the shellac and gutta percha, then add, with constant stirring, the sulphur and red lead. Use while hot.
| III.— | Raw gutta percha | 16 ounces |
|---|---|---|
| Carbon bisulphide | 72 ounces | |
| Eau de Cologne | 2 2/3 ounces |
This cement is the subject of an English patent and is recommended for patching cycle and motor tires, insulating electric wires, etc.
IV.—A good thick shellac varnish with which a small amount of castor oil has been mixed will be found a very excellent bicycle rim cement. The formula recommended by Edel is as follows:
| Shellac | 1 pound |
| Alcohol | 1 pint |
| Mix and dissolve, then add: | |
| Castor oil | 1/2 ounce |