Show Repairing Hard Rubber The bureau of standards says that hard rubber may be Joined by a bond of new hard rubber. A cement Is prepared pre-pared by adding one part of sulphur and three parts of crude rubber to fifty fif-ty parts of carbon bisulphide and three parts of alcohol. Several applications appli-cations of the cement are applied to the broken parts. These are finally Joined and held under pressure at a temperature of 100 degrees C. for four hours. A mixture of equal parts of gutta percha and bitumen dissolved in carbon bisulphide may also be used to cement the broken portions. |