Re: Casting WAX in silicon moulds

From: Ross Gates (
Date: Fri Jun 11 1999 - 20:32:14 EEST


We inject wax into silicon rubber tooling for investment casting. What
we have found is that it is best to use the wax from the foundry that
the parts are going to. Its seems every foundry has their own wax. It
has never been a problem in having them give you enough for the project.
A problem of injecting wax into soft tools, is that it has to be melted.
This can create sinks in the heavy sections as the wax freezes. Also,
after a few shots the mold retains the heat and it takes much longer to
pull a part, as much as an hour. Sometimes, it is better to go to an
epoxy tool and then it may be injected on a regular wax injection
machine. These machines inject wax that is softened under a lot of
pressure, so the wax hardens almost immediately, and there is not the
shrinkage problems you get when using silicone tooling.

Wax is used in investment casting. If you are going to the sand casting
method, then a hard master is used to produce parting boards or a
matchplate to use in that process.

Ross Gates
Select Mfg. Services Inc.

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