I have just returned from the Santa Fe Symposium and it was
great. For those of you that do not know it is a technical
conference for those involved in jewelry manufacturing. It is
the first conference that I have ever attended where the papers
are not thinly disguised marketing presentations. There was a
great effort to keep the papers technical or scientific in nature
and I did not see much if any marketing in the presentations.
Many were reports on research into precious metals metallurgy
such as “Understanding Heat Treatable Platinum Alloys” and the
"The Effect of Quench Temperature on Silicon Containing Low
Karat Investment Casting Alloys". Others covered process research
like “Metal Flow Optimizing - An Important Step to Successful
Casting” or “A Study of Machining Parameters and Their Effect on
the Surface Texture of Platinum Alloys for Jewelry Applications”.
It was overload. I learned more about why things
happen in those four days than I ever have from any school or
book. I would definitely recommend that anyone who is involved
in manufacturing jewelry should attend. It would also be of
interest to many bench goldsmiths but might be hard to justify
the cost of the conference. On the other hand the manufacturer
will learn things that will save money and time by reducing
failure rates and rework costs.
There were a couple of very good papers about thermal
decomposition of the CaSO4 (plaster of paris) binder in
investment that releases SO2 (sulphur dioxide gas). The SO2 is a
major cause of gas porousity. I turns out that the breakdown is
accelerated by the presence several things, carbon, metal oxides
(zinc, copper, silver), and hydrogen. These papers showed how an
incomplete burnout and poor melting practice will be the major
cause of gas porousity in our castings. While we may have known
this from experience the papers provide exact temperatures of the
reactions and some insight on how to avoid the breakdown and
reduce or eliminate this cause of porousity.
Enough rambling. If you are interested in why things happen
and what to do to correct them when they do then you might want
to consider attending the Santa Fe Symposium.
James Binnion Metal Arts
4701 San Leandro St #18
Oakland, CA 94601