Re: Gympsum material

From: Scott Nelson (
Date: Mon May 17 1999 - 22:21:58 EEST

USG makes rayite, I believe there are 3 grades, I only am familiar with
one, the machining grade, rayite-m I think.

It is not a slurry.... You mix it with water and pour into a casting
pattern, I use urethane rubber molds for this. In about 2-3 hours it is
cured and can be mounted on a milling machine as a solid block. It cuts
like butter with no dust, the rayite cuts off in big flakes leaving behine a
hard, polishable part with I will then often cast in aluminum filled
urethane for prototype tooling.

I have never seen rayite spread with a squeegee, it doesn't work that way.


-----Original Message-----
From: Doug Mitchell <>
To: Greg Pettengill <>
Cc: Rapid Prototyping Mailing List <>
Date: Monday, May 17, 1999 7:24 AM
Subject: Re: Gympsum material

>Greg Pettengill wrote:
>> I'm a little confused, maybe this is something I haven't seen
before.Rayite is a
>> castable material, what is this "You spread it with a
>> squeegee like device."
>> Best Regards
>> Greg Pettengill
>> (623) 846-8410
>Rayite was the group that was showing the US Gypsum material
>in their booth. It is a slurry material consisting of drywall
>mud. However it was thinned out. Therefore, you spread it
>around with a squeegee. Too thin for our application, although
>they did say that they were working on a thicker material.
>Doug Mitchell
>Ford Motor Company
>For more information about the rp-ml, see

For more information about the rp-ml, see

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