cure, removing the master, and then casting a duplicate part in
the cavity that remains.
Mold-making rubber is not inexpensive and has a limited shelf
life, usually less than six months. The mold that it produces is
permanent and can only reproduce the part for which it was
constructed. This is all well and good if you need to make a sig-
nificant number of the same parts. But what if you only need
an occasional casting or two? Is there a process that can make
a mold quickly, one that can be reused when the mold is no
longer needed?
Yes, there is. The product is called ComposiMold. It is a thermal
polymer that can be readily melted in a microwave or double
boiler, and poured around a master to produce a mold. When
all of the castings have been made, the ComposiMold material
can be reheated and returned to its jar or used to create another
mold. This cycle can be repeated many, many times.
In addition, ComposiMold does not smell (in fact, it has a
pleasant odor when melted), is non-toxic, and cleans up with
water. The process of mold-making can be completed in about
an hour. You can cast plaster, concrete, resin, silicone, ure-
thane, epoxy, wax, soap, and even chocolate in ComposiMold.
ComposiMold's only drawback is that it is somewhat soft and
you will only be able to produce a few castings from the mold
before it is no longer usable. If you still have the master, you
can always remelt the ComposiMold to make a fresh mold and
carry on.
Trial size
ComposiMold is available in 6, 16, and 32 ounce jars (1).
Because ComposiMold is measured in fluid ounces rather than
by weight, you can sometimes measure the volume needed
Easiest way to make molds -
MRH-Jan 2014
