Rhodium peeling off

my last post on this didnt bring any soloutions i had not thought of
but i also think most did not understand the problem the way i
described it so i am going to say it differently. the problem is
that ---- i plated a reuthinium / plat alloy ring and the rhodium
literally peeled off in micro thin sheets. now here is the part that
makes the situation maddening every thing else that i rhod. plate
sticks just fine i can plate stuff before and it sticks ! i can
plate stuf with this ring at the same time and it sticks. and i can
plate stuff afterwards and the plate sticks. but no matter what i do
the rhodium does not stick to this one piece.

now there is one thing about this ring the casting revealed two small
pits at the top near the channel set diamonds. to avoid burning the
diamonds i filled the pits i used 14k pd white hard solder. palladium
white gold solder is very close to the color of platinum and it has a
lower melting point than platinum solder ( which is not made out of
platinum anyway ) the stuff is fantastic for tipping on platinum
rings for those of you who are still in the torch age and cannot
afford laser technology any suggestions other than spelling errors
are most graciously and humbly accepted. although its begining to
appear that this problem has stumped the list best regards to all-

goo

Goo, now that you’ve described it a bit more…

one thought is how sure are you of your platinum alloy? I see your
supplier is trusted but could a mistake have happened at their end?
Have you had a chat with him/her?

Because the rhodium is applying but not ‘sticking’, that suggests to
me some basic incompatibility of the metals. If it were just a matter
of cleanliness the rhodium wouldn’t apply or would be spotty. By
chance if you happen to still have a sizing piece or maybe cut off
prongs you (or your caster) might be able to run some tests on those.

I’d also look very carefully at the electrocleaner. I’ve found once
its been overheated I get crappy results, although peeling has never
been one of them.

But the job is promised (I assume) and needs to be delivered. Your
choices are continue to unravel a mystery(who knows how long that may
take), start again($$$), or job out to a laser welder for the repair
with no rhodium.

I’d be really interested in how this finally washes out.

although its begining to appear that this problem has stumped the
list best regards to all 

Goo, as to why this is happening, as Neil said today, it’s somewhat
of a mystery - generally things either plate or not, as you know.
Perhaps you could flash plate first with gold, which is the usual way
to get plating to stick… Might work, but of course if it doesn’t
work then you have a yellow ring underneath. Test it on the shank,
perhaps. Or don’t rhodium at all. No rhodium is better than bad
rhodium.

i’m wondering about the dry electro cleaner thats avail these days ?
itseems like the the stuff is acid and soap mixed together then on
further consideration it does not seem thtat mixing acid and a base
would work because the two nuetralize each other.

goo