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