MOLDMAKING, B.C. - People have been making molds for thousands of years, dating back to ancient Egypt and China. Through the years, a variety of materials have been used to make molds including sand, wax, glue, animal fat, gypsum, alginate, metal, plastic, re-usable vinyl, gelatin and others.

OLDMAKERS TODAY still use a variety of materials, but a majority uses one of four different flexible rubber products for the following reasons: 1) these rubbers reproduce exact detail, 2)
flexibility allows for easy removal (demold) from the original model and the cast piece, 3) they generally give long life, allowing for multiple reproductions and 4) because they generally yield many reproductions, which also makes them cost effective.

hese rubber products are latex, polysulfides, polyurethanes, and silicones. The next few paragraphs review these common mold rubbers along with advantages/disadvantages of each.