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Platinum - copper alloy


#1

Orchidians- While at the recent LA jewelry show, I met a casting
house company representative that was praising the merits of a
platinum alloy that was made with copper (5 or 10%), rather than the
usual iridium, ruthenium, or cobalt. She claimed the alloy, which
came from Europe, was very easy to cast, very white in color, and
nicely workable, somewhere between irid and ruthenium alloys. And of
course, cost less.

I would appreciate any feedback on this subject, and also whatever
folks would like to say about casting platinum in general. While we
cast our own gold and silve, we always send platinum castings to
third party professionals. My experience is that while many casters
claim perfect results, often the castings have substantial porosity
(hooray for laser welders!), and occasional brittleness. They supply
the metal.

Jim Sweaney
mardonjewelers.com


#2

Hi Jim

Orchidians- While at the recent LA jewelry show, I met a casting
house company representative that was praising the merits of a
platinum alloy that was made with copper (5 or 10%), rather than
the 

I haven’t cast this alloy, however I have handworked it and while it
is very workable, it is a devil to polish, because of its “softness”.
The Pt/Ru is a little "harder"but finishing is much, much easier.

Lawrence
www.sabushkadesign.com


#3
I haven't cast this alloy, however I have handworked it and while
it is very workable, it is a devil to polish, because of its
"softness". The Pt/Ru is a little "harder" but finishing is much,
much easier. 

As I recall, 95Pt-5Cu is a stamping blend commonly used abroad. I am
not a fan of this alloy for investment casting. Funny how every time
iridium or ruthenium gets seen as expensive-Suddenly less expensive
but more problematic alloys get sudden attention. A truly good caster
can get decent results from nearly any alloy, but the upstream
consequences must be handled well. Remember Pt/Co? Suddenly casters
had it easier and bench jewelers had to learn to get rid of the oxide
coating when soldering. No big deal-but that is an unwelcome surprise
at the workbench. “responsibility does not end at casting”… :slight_smile:

Keep in mind we can and have made nearly all of them. All but the
patented ones.

Daniel Ballard
www.pmwest.us