I have a customer with a 14K white gold engagement ring that was
brought to me for rhodium plating. Her complaint at the time was that
the ring was “yellowing” and had a greyish haze to it, much like
silver when it tarnishes. So I proceeded to remove the balance of the
old rhodium and high polish, ultrasonic clean and steam clean and
then clean with electro cleaner and then the rhodium plating. All was
good. 10 days later she is back with the ring and the greyish haze is
back and it appears to be leaching through the rhodium. I cannot say
that I have seen this before. I asked if she had worn the ring in a
hot tub and she had. Is it possible that the bromine from the hot tub
is leaching its way back out of the gold? I have seen many bad things
happen to jewellery when worn in hot tubs and also when customers do
cleaning with bleach. Any input on this would be greatly
appreciated.
Thank you and take care, Paul Le May, Bracebridge, Ontario, Canada.
Having not seen the ring I don’t know if this is the issue, but
chlorine is the enemy of alloyed gold. I’ve seen so many prong
failures and pitting from folks wearing their jewelry in hot tubs and
pools.
Re rhodium the ring and have her not wear it in the hot tub to see.
I was going to cite hot tub use as a possible re-contaminant. I
would venture to say that is exactly the problem or a cleaning fluid.
though it can’t “penetrate” the original alloy It does affect any
plating and reacts with any compound or coatings (for instance, a
"micro coating" left by a polishing cloth or impregnated cloth
wheel/polishing disc). A grey haze is the key to identifying a
bromide contamination, and perhaps free zinc in the water or from an
old fashioned zinc sink, gardening items (water cans, frogs, tools,)
etc. can leave a slight tinge on the metal- equally any well water,
or artesian spring water with an extremely high mineral content or
city water and pools with high chlorine can be at the root of a
recurring problem. The only other contaminant is iodine which can be
in medicines or topical preparations. If none of the above
developing film or handling photographic chemicals in printmaking
would recontaminate the piece. It is not something you failed to
address in your initial treatment of the piece.
Since you have stripped the piece, cleaned it and replated it once
already, the only thing left to do is ask the client to rexamine
what she is doing. We know the gold in the alloy is non reactive,
however the nickel is. Other than recasting/remaking the ring I
cannot think of any reasonable process you can do as a small studio.
Electrophoresis is the only potential but not reasonable process left
to solve out contaminants at an almost atomic level. it would be far
easier to copy or replace the piece than finding a lab (or
university) with the capacity to process one, single ring! Not to
mention the expense potentially involved if a university doesn’t
agree to take it on as a lab project for students in a metallurgy
programme. there is no magic soak or treatment that will neutralise
it by immersion, and no chemical process that will pull any ions out
of the alloy that is reasonable to do in the studio. A surface
sealant will look horrid. If you could raise the karat that would
help but its not possible without recasting it. in fact, if it were
18 kt.
I doubt you would be having the problem at all. It is an intrinsic
problem with 14 Kt whites (and the reason I don’t use it or
recommend its purchase to clients even if they insist!!).
Since it recurred after only ten days the problem has to be with
something the client is doing since I’m presuming she had the ring
and it was intact for some time before the problem appeared. However,
if she bought it recently and the problem appeared within a year or
perhaps two the casting could have had a problem. A time period
longer than that it was definitely abuse by the wearer and nothing
you can do will correct it reasonably or that will be profitable for
you except remaking it. Even if you remelted the gold, used a good
refining flux and raised the karat the nickel based alloy would still
be a potential problem. Sending it to a refiner is not reasonable
either. Dissolving the gold and reclaiming it borders on overkill,
but may be the only way to reuse the gold in it and at a 57-53%
content it is hardly worth it. I would advise recasting the ring, if
not purchasing another semi-mount or whatever it is ( unless of
course the purchase was fairly recent) or if the client has Jeweler’s
Mutual or a similar policy take advantage of it, by becoming the
replacing firm!,Again she has already admitted to wearing it in a
hot tub so that could be a warranty breaker even if insured. You have
to weigh her actions against your diligence to find a solution, and
go with the one that helps keep you in business since the piece
wasn’t one you created. rer
Probably galvanic corrosion of the rhodium. The slightest pinhole in
the rhodium will allow the contact of the underlying gold alloy and
the rhodium plate. Hot tub water is a really good electrolyte, so
two dissimilar metals in physical contact exposed to an electrolyte
is the definition of a battery. The corrosion will be greatest at
the interface between the gold and the rhodium and this will eat
under the plating and erode it off the ring as it is so thin.
Interesting theories advanced… Here is another possibility on why
plating doesn’t last. Years ago I made a Sterling silver ring that
my husband wore for only a day when pits started to develop. I had
the ring rhodium plated as a possible solution. It looked great!
However it was only a short time (maybe a week) before the plating
was gone where his fingers rubbed on the ring. The same ring cast in
white gold and un-plated was worn for years with no problems. It was
HIS chemical makeup that was to blame and explained why he had always
had problem keeping silver fillings in his mouth.
I would tell the client that the chemicals in pools and hot tubs
will affectthe alloys in white gold. If that is part of her life
style I would recommend that she have the ring remade in platinum
which will not have the same problems, and I personally would offer
her credit for what she paid towards the new platinum ring mounting.
You will not lose any money that way and the customer will have a
ring that she can wear 24/7.