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Repairing old platinum ring


#1

I had a PLAT ring ring come through the shop that needed prong work
and and stone replaced. The ring had a lot of pave’ dias. around the
center and one of the melee had come out and the center stone was
loose. After doing the prong work, I started to tighten all of the
stones and realized that when I applied and pressure to the top of
the ring, it would bend. I suggested the we do some gallery work
under the center stone to make the top of the ring stronger. Then
the question was raised that this was a seventy year old ring and how
could it have survived this long and suddenly need this type of work
done on it. The ring was not obviously worn and the only thing I
could think of is, that over time, with different people working on
it, it just became soft. I am not sure if that makes any since to
anyone but if someone could advise me on this I would appreciate it.
My boss was the one that asked the question and I would like to give
him and educated answer.

Thanks,
Steven


#2

Hello Steven;

When you work on those pieces, you need to fill the underside of the
ring with shellac or Jett Set if you are going to be putting any kind
of pressure on it. Those rings are typically thin metal, and
intricate piercing makes them bend even more easily. Heat the shellac
on your steel bench block, then moisten your fingers and gingerly
mold it into a ball and pack it up under the top of the ring. (For
Jett Set, heat in a cup in the microwave) Before it completely cools,
push it onto a ring mandrel to form the shellac so that it can be
held on a mandrel of with a benchmate inside ring clamp. The shellace
will ooze out the holes and around the sides, but you can easily pick
and scrape it away from areas you need to work on. Melt out the
shellac gently with a torch (or heat the Jett Set in hot water, no
rings or other metal in the microwave, of course). The last of the
shellac can be dissolved out in alcohol. I put the article in a small
jar of alcohol and let it sit for a long time, sometimes speeding
things up by setting the jar in a basket perched in the ultrasonic
with it on).

There are many cases where articles won’t withstand the pressure of
bright cutting, engraving, hammering bezels, etc., without the
support of shellac or one of the thermoplastics. Sometimes its the
only way to hold on to something while working on it. Shellac is an
essential tool for jewelers, especially during setting work.

David L. Huffman


#3
The ring was not obviously worn and the only thing I could think of
is, that over time, with different people working on it, it just
became soft. 

Hi, Steven. It’s difficult (impossible) to say what’s up with your
ring without having it, but there are thoughts… If it’s really
that old, there’s a good chance it’s a platinum ring, which is to say
pure platinum, not 10% iridium or anything. Fine platinum is very,
very soft, somewhere between 18kt and 22kt, to my touch (don’t know
Brinell or anything for that). Those old pierced rings were and are
set in shellac, where the entire ring top is filled with it. If you
do repair work without shellac, you need to make allowances in your
touch. It may actually have “become soft”, but not so a human could
tell the difference - annealing happens over time, but lots of time.
More likely people like you have replaced stones and things and
removed more and more of the structural metal, little by little - not
accusing, it’s just the ring’s life history. Those old pierced rings
(people call them filligree, but they’re not) depend on engineering
for strength - a disk of gold is flimsy, but if you dome it, it
becomes strong, stuff like that. Bottom line: Maybe the ring has been
weakened, over time - maybe some of the metal between the stones is
broken and stuff, too - happens with pave at times. It could be that
it is as strong as it’s ever been, and you’re just not used to
working on a finely pierced, pure platinum piece - it takes a light
touch, and they’re not intended for wear while doing dishes and the
like to begin with. I would agree, though, that installing “Flying
Butresses” is inappropriate, though maybe a little more structure
would help in places. Again, there’s no real way to know over the
internet…

http://www.donivanandmaggiora.com


#4

The best way I have found is to fill the hollow area in the back of
the ring with shellac or jett sett. I love the jett sett its much
easier to remove but a bit more expensive.

Bill Wismar
www.metalbendersgallery.com


#5

If using one of the thermoplastics, you can soften it afterwards by
putting the whole thing (ring and all) in the microwave as long as
it’s under water.

I don’t have a crockpot for pickle yet so have to heat it in the
microwave and I regularly heat it with whatever I’m pickling. You’re
okay as long as the liquid covers the metal article.

Helen
UK