Rhodium Plating and diamonds black reflection

What causes the diamonds to have a black reflection on some of the
pieces we rhodium plate? The peice is cleaned and checked under 60
power to be certain it is clean. This has happened a couple of times
in the past few months. There does not seem to be any way to remove
the “shadow” once it is there. How do we avoid this?

We try to buff off any plating on the outside of the ring, but
obviously can not get into the seats or channels of the stones.

This “shadow” will not come off from steam, ultra sonic, amonia,
acetone, or anything we can think of.

Any suggestions?

try and ionic cleaner, I have had this work when all else fails to
clean behind set stones.

Frank Goss

Am I correct in assuming that you’re talking about repaired pieces
rather than new production? If so, I’d suspect there was still some
dirt around the girdle, which, as you say is hard to get out before
soldering. Boiling Lye will often get in tight areas. As a hedge you
might try packing the open backs of the stones with handiflux or
similar before you solder. You might not be noticing the burn until
final inspection when everything is bright by comparison which may
mislead you about it coming from the rhodium.

Another thought is that the ‘shadowed’ stones although clean, may
just have been overheated.

If the stones are smallish you might consider that you may just have
to replace X percentage of melees now and then. There’s a tin of
melees on my bench for that purpose. If they are larger you may have
to yank them out and repolish.

a little piece of literary

when the client demands i make haste, heat shield or mudd doth
protect the crudd, under the diamond from burning up time i would
otherwise waste - and… if still this should fail to fall short of
the goal of returning your work to perfection . into the handyflux
the item should go then under the torch with care to just melt the
flux, so you wont shell out bucks, because when cool to the touch
sparex soloution is a must,then you both will be out of your pickle

goo