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Annealing platinum


#1

Hello, I don’t have ‘proper’ full-on reducing equipment but just use
an ordinary propane torch for my work with gold and silver. A
customer has asked me if I can set some stones into a pre-made plain
platinum wedding band for her. I want to help because she is a good
customer but am a bit wary about working in a new metal. However, I
figure that as long as I can anneal it successfully then I should be
fine to just drill and grain set the stones (although I know this will
be harder work than with gold!). So - my question is about annealing
platinum…is it OK to anneal with the orange part of my propane
flame on a non carbon block? Thank you in advance for your help. Best
wishes, Harriet Hitchin, UK


#2

Harriet, You should be able to set the stones without annealing the
platinum, and in my opinion you will be pleasantly surprised at the
way the platinum responds to setting…I much prefer it to gold. I
cannot, I am sorry to say, answer your question about annealing with a
propane torch.

Jim Malone
Diamond Point Metalsmiths
http//www.adirondackjewelers.com


#3

Hi Harriet. To anneal platinum you should hold it at a nice orange
for about a minute and then quench. You’ll need proper eye protection

  • it gets exceedingly bright. Also you’ll need a very clean surface
    as platinum gets easily contaminated. You’ll love to do the setting
    in platinum, it’s the polishing that will make you go “what the…”.

Good luck, Mike.


#4

Don’t anneal the platinum it is relatively soft to begin with. The
reason it wears longer is its density not its hardness. You can bead
set in platinum about as easily as with silver I have found.
Depending upon the alloy it can be as easy as fine silver to set
stones in. Also it dead sets. By that I mean it does not rebound like
copper alloys of gold and silver. Once you push a prong down it will
not have a tendency to spring back a little. You can get a wealth of
info from the platinum guild in California I am sure someone out
there has their number or it can be found in the JCK directory issue.


#5

Hi Harriet: You shouldn’t have to anneal platinum at all, at least not
for stone setting. Even a die-struck band, although stiffer than a
cast article, is going to be considerably softer than 14 karat white
gold, and setting as you describe is a dream in platinum. It’s my
guess that “bright-cutting” was probably devised as a setting method
for platinum, since I see many examples in platinum from before white
gold was widely in use. Don’t forget to use a little Oil of
Wintergreen (any drugstore) on your gravers. Just dip the tip in a
tiny cotton ball soaked in it. It’s an old engraver’s favorite
lubricant, and platinum tends to “hang” a bit on steel, so you really
will benifit from its use. You could, of course, try “flush” setting
them too, for a more modern look. Nice article a couple months back
on that technique in Professional Jeweler. As for annealling
platinum, if you should feel you need to do this, then keep the metal
scrupulously clean, place on a clean fire brick, and bring it to a
bright orange and hold it there for a minute or so. This would be
around 1600 degrees Faranheit, I believe. It has to be held at that
temperature for a while. Quench it in clean water afterwards, but be
carefull to pick it up with clean tweezers, and pickle it afterwards.
Causing no contamination is much more critical with platinum than
with other metals, since, at its high melting/soldering temperature,
other metals like gold and silver are already flowing readily, if not
boiling, and they’ll just dive right into platinum’s often
microscopically porous surface, where they reek hell with the metals
grain boundaries.

David L. Huffman


#6

Jurgen Maerz’s instructions for annealing platinum include keeping
the metal at 900 C degrees for 60 seconds. I have never maintained a
temperature for a period of time when annealing any other metal. Have
I been annealing gold and silver improperly, or is this process
unique to platinum?

Thanks,
Jamie


#7
Jurgen Maerz's instructions for annealing platinum include keeping
the metal at 900 C degrees for 60 seconds. I have never maintained
a temperature for a period of time when annealing any other metal.
Have I been annealing gold and silver improperly, or is this
process unique to platinum? 

Jurgen is correct. For full softness to be reached with a 900C
anneal, it does indeed take about a minute or so. If you heat it
higher, it takes less time, but with platinum, you then start to get
some grain growth, which isn’t desireable. Platinum differs some from
the other precious metals we normally use in that they (gold and
silver alloys) generally anneal more quickly, at least at the
temperatures we normally use, around 900 F and up (a low, barely
visible red glow or a bit more). Those temps are normally used
because they’re easy to judge visually. At those temps, gold and
silver anneal fully in seconds. However, if you’re furnace annealing,
you might be using an annealing temp a hundred and fifty degrees
lower, or thereabouts, and then, it can take fifteen minutes or more
to fully anneal the metal. It’s all a tradeoff between temperature
and time. Thickness of the metal and the size of the grain structure
also has an effect. Thinner metal with smaller grains, anneals a bit
more quickly. The same is true with platinum. Though a heavy section
of stock at 900 can take a full minute to fully anneal, a length of
28 guage wire will take just a moment.

Peter