Subject: pewter casting-pit problems

From: [email-masked]
Date: 21 Sep 1996 18:58:37 GMT

using a centerfugal casting machine and vulcanized rubber molds I have a 
problem of pits on smooth surfaces of my castings. I have tried 3 
different types of pewter,different speeds,different pressure,different 
molds,drying my powder and I still come up with pits. I haven't had the 
time to research to find if weather affects casting. Can anyone help?

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From: Andrew Werby <[email-masked]>
Date: 22 Sep 1996 18:22:05 GMT

>time to research to find if weather affects casting. Can anyone help?

[If these are heavy solid pieces, your problem is probably shrinkage. 
The pores come from liquid metal inside the casting pulling metal from 
the surface. The answer is bigger gates or shrinkage reservoirs. I have 
posted an article about an analogous problem in silver castings on my
page under "Techniques of Sculpture."]

Andrew Werby - United Artworks

http://users.lanminds.com/~drewid