Tim Williams wrote:

...

What metal are you casting? If it's aluminum, and if you're getting lots
of bubbles, have you tried degassing the melt? - GWE


I think his problem is bubbles under the plaster, and being too picky about
them. (

I've seen bubbles in plaster removed in a vacuum chamber (on a This Old
House episode where they do a factory tour of an investment casting
place). I've only poured one casting ever in my life, though, so I'm no
expert.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com