I must question Peters response regarding investment powder
safety. It has always been my understanding that investment powder
is a carcinogenic, regardless of how large or small the particles
are. Once ingested these particles lodge themselves in the lungs
and become impossible to remove.
I'm not a medical professional, so of course, what I "know" is only
from what I've read and been told. Might be wrong. But my
understanding is that larger particles are actually more able to be
removed by the lungs, via cilia action. Also, the initial investment
particles aren't quite as sharp, and are thus perhaps less irritating
along the way. Certainly, they're not good to breathe, and I did not
mean to imply that investment powder wasn't dangerous. It is, and
the labels on the products are careful to advise as such. But it's
not the most dangerous form of silica dust. The particles released
when quenching a cast flask are considerably more irritating, and in
the size range and shape that the cilia in the lungs cannot well deal
Or so I've been told.
As with ANYTHING ever found on Orchid, remember that information
passed on here is usually unverified, and only as good as the source.
Often, in terms of jewelry making technology, we're reasonably
considered experts. But we also often pass on info that's merely
what we've come to believe, right or wrong.
If you're concerned, go find properly researched, published data on
the subject, and if you've the time, report back to us. I'd
personally like to know what that data has to say on the subject.