Re: [hobbicast] gassy aluminum
I've made many porosity testers. It is done with a vacuum pump. The
procedure is to place a very small sampling cup of liquid aluminum under a
bell jar and pull a vacuum on it while it is still liquid. If there is much
gas present in the aluminum the sample will swell up like a muffin in the
oven. So you degas and check it again until you can pull a vacuum on the
liquid sample and, while watching its surface, there are no detectable
bubbles that rise to the surface. It is then considered "dead" metal. No gas
whatsoever. You'll be able to polish and chrome plate a casting made from
----- Original Message -----
From: "LLandstrom" <creepinogie@...>
Sent: Sunday, December 31, 2000 5:06 PM
Subject: Re: [hobbicast] gassy aluminum
> Anyone make a homemade porosity testor with a pressure
> cooker of known volume and an air guage?
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- Sounds like they needed a different pattern maker. I
never heard that one before. Don't think I'll try it
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