RE: Investment Casting of Silicone Rubber

From: 071 Bassam Sarkis (
Date: Thu Nov 30 1995 - 20:58:53 EET

Al Hastbacka wrote:

>Has anyone on this list ever tried to use investment casting techniques
>to make silicone rubber models. What I have in mind is the idea of
>making a ceramic mold as you would if you were investment casting
>metal. The ceramic mold would then be autoclaved to melt out the
>master pattern. Then, instead of pouring a metal into the mold,
>silicone rubber would be poured into the ceramic mold. Once the
>silicone rubber has set up, the rubber model would be removed by
>breaking away the ceramic.

>If you have any experience with a process similar to this, I would
>appreciate feedback.

Why would anyone want to do this, especially in view of the

-You would need one wax pattern for each silicone rubber model
needed. The time and money spent in making these patterns is
likely to be more costly than the value of the silicone rubber models
without even considering the cost of ceramic molding and casting.

-Investment casting wax patterns are typically made from machined
aluminum injection molds. Once again, the time and cost of
manufacturing such mold is better spent in fabricating some sort of
tooling that can be used for the silicone directly without having
to go through the investment casting process.


Bassam Sarkis Phone: 1-514-322-2371
Rapid Prototyping Engineer Fax: 1-514-322-1340
Cercast Group
3905, Industrial Blvd E-mail:
Montreal North
Quebec, Canada
H1H 2Z2


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