Instructions in the manipulation of hard rubber or vulcanite for dental purposes . shaft, is very useful in cleaningunder the pins (Fig. 8). It can be made outof an old excavator. It is advisable to rubthe pins with a small pledget of cotton dippedin strong alcohol, especially w^here there areany particles of foreign substance adhering tothem. The importance of removing every particleof wax from the mould is demonstrated bysome experiments made by the writer to ascer-tain the efiect of lard-oil, yellow wax, whitewax, and paraffin upon rubber during vulcani-zation. Kubber was vulcanized in cont
Instructions in the manipulation of hard rubber or vulcanite for dental purposes . shaft, is very useful in cleaningunder the pins (Fig. 8). It can be made outof an old excavator. It is advisable to rubthe pins with a small pledget of cotton dippedin strong alcohol, especially w^here there areany particles of foreign substance adhering tothem. The importance of removing every particleof wax from the mould is demonstrated bysome experiments made by the writer to ascer-tain the efiect of lard-oil, yellow wax, whitewax, and paraffin upon rubber during vulcani-zation. Kubber was vulcanized in contactwdth these substances separately; and in eachcase the integrity of the rubber was oil acted more energetically than theother substances, leaving the mass, when cold,^ semi-fluid. CLEANSING THE MOULD. 17 The next step is to cut grooves, or gates, in the plaster,radiating from the mould to the outer edge of the tiask, toallow the excess of rubber to flow out when the sections ofthe flask are being brought together. Fig. 9 represents thelower section so Another method is to cut a groove encircling the mouldabout midway between it and the edge of the flask, thenmaking numerous small grooves radiating from the mouldto the encircling groove, and from this a few larger ones tothe circumference of the flask. Fig. 10 represents theupper section prepared in this manner. This having beendone, the mould should be carefully brushed, to remove allloose particles of plaster. 18 INSTKUCTIONS FOR MAKING VULCANITE WORK. IlG. 10.
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Keywords: ., bookcentury1800, bookdecade1860, bookidinstructions, bookyear1865
