In years past, I have cast some silver and gold jewelry successfully, techniques and equipment that are FAR from "by-the-book". Until this week, I had never used a vacuum de-bubbler. My burnout oven was a metal coffee can on top of a hotplate that surely never reached so much as 700 deg F (flask never glowed orange). And my centrifugal caster appears to be home-made (I bought it used), and only spins for about 30 seconds. With all this... I have cast some pretty nice stuff. But I'm trying to do better. So...