Melt 1 lb. resin in a pan over the fire, and when melted, add ¼ lb. of pitch. While these are boiling add brickdust until, by dropping a little on a cold stone, you think it hard enough. In winter it may be necessary to add a little tallow. By means of this cement, a piece of wood may. be fastened to the chuck, which will hold when cool; and when the work is finished, it may be removed by a smart stroke with the tool. Any traces of the cement may be removed from the work by means of benzine.
The heat necessary to melt the ordinary turners' cement is liable to warp thin plates of brass, and in some cases, as for example circles of mathematical instruments that require to be graduated, this is very objectionable. In such cases plaster-of-Paris is the best cement to use.
½ oz. rosin, ½ oz. pitch, 1 oz. beeswax; melted together, sufficient fine brickdust added to produce desired consistence.
2 lb. rosin, 2 lb. Burgundy pitch, 2 lb. dried whiting, 2 oz. yellow wax; melted and mixed together.
½ lb. black rosin, 1 oz. yellow wax; melted together, and poured into a tin canister.
Take Burgundy pitch, 2 lb.; rosin 21b.; yellow wax, 2 oz.; dried whiting, 21b.; melt and mix.
Black rosin, Â£ lb.; yellow wax, 1 oz.; melt together, and pour into a tin canister. When wanted for use, chip out as much as will cover the chuck to 1/16th of an inch, spread it over the surface in small pieces, mixing it with an eighth of its bulk of gutta-percha in thin slices; then heat an iron to a dull red heat, and hold it over the chuck till the mixture and gutta are melted and liquid; cool the iron a little and with it stir the cement until it is homogeneous; chuck the work, lay on a weight to enforce contact, leave it at rest for half an hour, when it will be ready for the lathe.