Ebonite is properly the name for black hard rubber, and vulcanite for the colored products such as used by dentists and others.
GUTTA-PERCHA.
Gutta-percha is prepared by coagulation from the juice or sap of several trees, among others the Isonandra gutta, of Borneo and the East Indian Archipelago. The product gutta-percha is identical in composition with india rubber. It is hard at all ordinary temperatures.
Its manufacture includes purification and mastication. It is far more amenable to treatment than is india rubber. Many materials are mixed with it as adulterants or otherwise in the factories.
It is more useful in the form of sheets. These when heated to 122° F. (50° C.) become pliable and can be moulded by pressure to any degree. At the temperature of boiling water it becomes pasty and adhesive, and at 266° F. (130° C.) it is so soft that it may be considered as melted.
It is an admirable moulding material. Stereotypes and other relief or intaglio images can be made by pressing it while heated. These are often absolutely perfect reproductions of the original.
Dishes for photographic purposes, etc., are easily made out of the sheet. By gentle warming they become pliable, and a greater heat makes surfaces capable of adhering by pressure.
Tubes can be made by the squirting process, as used for india rubber. Wires are coated with it in a similar manner.
It has several defects. It is not durable if exposed to the air with consequent changes of temperature. It is also too easily softened by heat, as of course no hot liquid can be introduced into a gutta-percha vessel. The Parkes cold curing process can be applied to it, which makes it more indifferent to heat. This is applied by dipping an instant and drying. After several repetitions the period of dipping is prolonged and ultimately it is left immersed some time. If left immersed at first it would dissolve.
It is soluble in most caoutchouc solvents, particularly in carbon disulphide.