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Platinum bending

Hi all,

About 6 months ago I made an engagement ring using cast 950
irridium platinum. The ring contains an emerald cut diamond & 2
baguette diamonds. My question is, the bottom of the shank is
bending according to my customer(she didn’t do anything). The
shank is fairly substantial-not super heavy though. How do I
harden the shank? Thanks in advance.

David Ginis
Ginis Goldsmiths


Sounds like your customer dosen’t know their own strength. I
would recommend a new and heavier shank as compressing or
hammering the shank to harden would enlarge and thin it & sizing
would take the temper back out. A new shank using bar stock
would also be more dense as well as stronger. BTW you did’nt say
just how thick the shank is.


Unfortunately, 950 iridio platinum won’t harden up all that
much. It’s not an alloy you can heat treat. Work hardening is
the only way, and with an already cast piece, this is difficult.
You can hammer it and bend it around, straighten it again, etc.
This will help. But you won’t get really hard out of it, only
perhaps some improvement. And unfortunately too, doing all this
will then require refinishing most likely, which will then
further thin the shank at least a little bit…

You might consider, if you can do so cleanly, putting on a new,
heavier shank. This time, forge it from 900 iridio platinum,
which is a bit harder, and using forged/rolled metal will help a
GREAT deal too.

he other option, maybe the most practical, is to just straighten
it. If She bends it again, you’ll straighten it again. After a
few cycles through this, it won’t be so soft… Not the best
public relations, though. but platinum being as it is, if the
metal is sound, she’s not likely to actually break the thing.
One note: After you straighten it, spend some time with a
burnisher, burnishing the surface good and bright again, instead
of sanding or emerying out any marks left. This is more work,
but you can smooth the shank again this way with almost no metal
loss, and the result will also be a somewhat tougher, harder
surface skin on the metal that will also help it to resist
future bending. Not completely, but it will help.

Peter Rowe

It depends on the alloy, Hoover and Strong has SK platinum alloy
that can be heat treated to harden , Haffner from Germany also
has an alloy that can be heat treated very successfully

  Sounds like your customer dosen't know their own strength. 

Steve- This isn’t always the reason that the ringshanks will
become misshapen. I noticed that many customers who came to me
with this problem had jobs where they would constantly be picking
up a phone or something else and this over time would change the
shape of the ring. It wasn’t a one time heavy blow to the ring
but a gradual process.