RE: RP and Jewelry Question

From: Jeffrey Everett (
Date: Wed Oct 29 2003 - 00:33:48 EET

In addition to Rod's comments, I offer the following. Back in the 1980's I
experimented with using ringless casting techniques for centrifugal
investment casting from photopolymer patterns. Phosphate based investment
does not have sufficient permeability for vacuum casting. I did have
problems with ash residue from the photopolymers available then, but
otherwise produced good castings. The investment is quite hard. I had to use
very slow burnout routines with large patterns because expansion of the
photopolymer would crack the investment. Quenching the hot flask did not
shatter it, a hammer was needed to break away the investment from the
castings, followed by a hot bath in a hydrofluoric acid replacement which I
forget the name of. All the casting supplies and materials required were
purchased from a dental supply house. I hope this helps.

Jeffrey Everett

> -----Original Message-----
> From: []On
> Behalf Of Rod McCormick
> Sent: Tuesday, October 28, 2003 1:30 PM
> To: RP list3
> Subject: Re: RP and Jewelry Question
> Doug Bucci at Moore College of Art has been experimenting using platinum
> casting investment (stronger, higher temp) to cast stereo-lith models.
> Perhaps that would help for the perfactory material.
> Rod McCormick
> University of the Arts
> > Scott,
> >
> > For several months I have been seeking to verify that
> Perfactory models can
> > indeed be directly investment cast. So far I have not had much luck.
> >
> > If you are seriously considering doing this, then I would
> strongly suggest
> > that you use the Ceramic Shell process instead of conventional
> jewelry/dental
> > type investment materials. It is capable of handling much
> higher temperatures
> > and would help ensure a successful outcome.
> >

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