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Contaminated rhodium


#1

Are any chemists out there that can explain how sterling silver can
contaminate rhodium plate solution? Any suggestions on how to reclaim
the rhodium from the solution? I know I can try to filter the plate
solution with activated charcoal, but can I drop the rhodium out of
the solution completely?

Gary L. Mills


#2

I can’t advise you on refining the rhodium solution - I’ve tried it
with activated charcoal myself, but could never filter it well
enough. But I can empathise with the silver issue - I’ve had it
happen to me, too. What I found was that the silver wires I was
using for contacts were going black and green, and this was gradually
contaminating the solution. To avoid this happening, I started using
fine silver wires, and the problem stopped immediately. If you’re
trying to plate silver items, then my experience suggests a few
things you could try:

  1. Oxidise the items, then pickle them, then barrel them - this will
    effectively cover the items with a thin layer of fine silver, but
    there may be patches that aren’t covered. Also, it wouldn’t work for
    items that need a proper polish.

  2. Silver plate the items first, then rhodium them. I only do
    rhodium and gilding - are there any experts that know if silver
    plating will work?

  3. Don’t rhodium the items; unless the firestain is terrible, isn’t
    silver white enough?

Jamie
http://primitive.ganoksin.com


#3

Silver is white enough, but Rhodium is used over silver to keep it
from tarnishing. I generally work in platinum, gold or palladium,
but do a lot of repairs on rhodium and nickel plated silver.

Pineforest Jewelry Inc./PFJ Inc.
Gary L. Mills


#4

The problem is the rhodium bath is ruined by silver. So, most nickel
plate the silver first to avoid it.