Has anyone ever done any research or run across any
technical papers or have first hand experience concerning the
integrity of the stones after they have been through the
casting process ?
Bill, I have not heard of any such research. I have heard many
papers at the Sante Fe Symposium about casting with stones and I
recall no mention of problems. I have been casting stones in
place for a couple of years and have noticed no decrease in
durability or other problems. the fact that so many major
manufacturers are using this process suggests that it is not a
concern. Many stones are heated to the same temperatures during
some repair procees, without any problems.
Also, some technical papers I have run across say to put boric
acid in your investment to protect the stones. Does anyone
know the purpose of the boric acid and if it is necessary ?
I use boric acid in my investment and cast using a normal
burnout cycle. the boric acid coats the stones just like fire
coat does when soldering. I believe it keeps oxygen from
reaching the surface of the stone and not allowing it to
oxidize. I can’t tell you exactly or technicly why but I know
it works. It is very important that the stones be impecibly
clean to keep them from being scorched.
I am teaching a class at Revere this summer on casting with
stones in place and we will actually be doing several castings
with different shapes and types of stones and injecting a wax
mold around stones. Any one interested can contact the Revere
Academy for specific dates at:
Revere Academy of Jewelry Arts
760 Market Street, Suite 900, San Francisco, CA 94102
phone: (415) 391-4179 fax: (415) 391-7570