This section is from the book "The Tinman's Manual And Builder's And Mechanic's Handbook", by Isaac Ridler Butt. Also available from Amazon: The Tinman's Manual And Builder's And Mechanic's Handbook.
1. Cut up one pound of India rubber into small pieces and diffuse in half a pound of sulphuric ether, which is done by digesting in a glass flask on a sand bath. Then add one pound pale linseed oil varnish, previously heated, and alter settling, one pound of oil of turpentine, also heated beforehand. Filter, while yet warm, into bottles. Dries slowly.
2. Two ounces India rubber finely divided and digested in the same way, with a quarter of a pound of camphene, and half an ounce of naphtha or benzole. When dissolved add one ounce of copal varnish, which renders it more durable. Principally for gilding.
3. In a wide mouthed glass bottle, digest two ounces of India rubber in fine shavings, with one pound of oil of turpentine, during two days, without shaking, then stir up with a wooden spatula. Add another pound of oil of turpentine, and digest, with frequent agitation, until all is dissolved. Then mix a pound and a half of this solution with two pounds of very white copal-oil varnish, and a pound and a half of well boiled linseed oil, shake and digest in a sand bath, until they have united into a good Avarnish. - For morocco leather.
4. Four ounces India rubber in fine shavings are dissolved in a covered jar by means of a sand bath, in two pounds of crude benzole, and then mixed with four pounds of hot linseed oil varnish, and a half pound of oil of turpentine. Dries very well.
5. Flexible Varnish. - Melt one pound of rosin, and add gradually half a pound of India rubber in very fine shavings, and stir until cold. Then heat again, slowly, add one pound of linseed oil varnish, heated, and filter.
6. Another. - Dissolve one pound of gum dammar, and a half pound of India rubber, in very small pieces, in one pound of oil of turpentine, by means of a water bath. Add one pound of hot oil varnish and filter.
7. India rubber in small pieces, washed and dried, are fused for three hours in a close vessel, on a gradually heated sand bath. On removing from the sand bath, open the vessel and stir for ten minutes, then close again, and repeat the fusion on the following day, until small globules appear on the surface. Strain through a wire sieve.
8. Varnish for Waterproof Goods. - Let a quarter of a pound of India rubber, in small pieces, soften in a half pound of oil of turpentine, then add two pounds of boiled oil, and let the whole boil for two hours over a slow coal fire. When dissolved, add again six pounds of boiled linseed oil and one pound of litharge, and boil until an even liquid is obtained. It is applied warm.
9. Gutta Percha Varnish. - Clean a quarter of a pound of Gutta Percha in warm water from adhering impurities, dry well, dissolve in one 'pound of rectified rosin oil, and add two pounds of linseed oil varnish, boiling hot. Very suitable to prevent metals from oxidation.