This is the process for making simple rubber block molds using urethane rubber. In this video we used 74-41 rubber but you could also use 74-20 for delicate patterns, or 74-45 for casting abrasive concrete. This kind of mold is ideal for casting plaster, soap, candle wax, as well as many other materials. Resin may be cast into a urethane mold, but proper release (2300) must be used to insure that the liquid resin does not bond to the urethane rubber mold.
Mould Making & Casting: urethane mold process for candles, soap, plaster, or concrete
This is the process for making simple rubber block molds using urethane rubber. In this video we used 74-41 rubber but you could also use 74-20 for delicate patterns, or 74-45 for casting abrasive concrete.
