Rhodium plating in studio

Hi folks! I would like to set up a very small scale plating system
(bought all the equipment second-hand many years ago) mainly to
plate rhodium on silver so my works will retain their nice
silver-color and their high shine over time. I am referring to flat
mirror-finish pendants which, of course, instantly show up any kind
of staining or uneven color, no matter how minute. I conferred with
a plating consultant who looked over my equipment and recommended a
sequence which dispensed with the nickel pre-plate which I thought
was needed to seal off the silver before applying the rhodium. He
said that bright nickel was not realistically feasible on such a
small scale (a beaker) because of the (relatively) many chemical
additions required for brighteners. When I got home, I read through
my books and found all plated with nickel first, and the MIDAS
Plating Guide even went so far as to say “The rhodium solution is
easily contaminated and care sould be taken not to introduce
impurities such as bare silver, copper, brass, bronze,iron, steel,
or any base white metal”. The consultant is a chemist who has years
of practical experience setting up plating facilities. Will not
having the nickel barrier on sterling silver contaminate my rhodium
bath and give me bad color? If I can’t get a nice silvery color (as
white as possible), there is of course no point in doing it. Does
anyone out there successfully do rhodium plating with really good
color on a small scale? Any help in getting a proper set-up and work
sequence would be greatly appreciated!

Thanks.
Janet in Jerusalem

copper is fine - generally plate copper over silver - then rhodium
over copper - copper won’t contaminate your rhodium bath - we use
copper wire to attach small/intricate pieces to the connection.
andrew goodell

Hi folks!

Haven’t had any responses to my post last week :o(—perhaps because
it was on a Friday?—so I’m posting it again in the hopes that
soome kind Orchidian will come to my rescue…:o)…

I would like to set up a very small scale plating system (bought all
the equipment second-hand many years ago) mainly to plate rhodium on
silver so my works will retain their nice silver-color and their
high shine over time. I am referring to flat mirror-finish pendants
which, of course, instantly show up any kind of staining or uneven
color, no matter how minute. I conferred with a 'plating consultant’
who looked over my equipment and recommended for me a sequence which
dispensed with the usual nickel pre-plate which I thought was needed
to seal off the silver before applying the rhodium. He said that
bright nickel was not realistically feasible on such a small scale
(a beaker) because of the (relatively) many chemical additions
required for brighteners. When I got home, I read through my books
and found all plated with nickel first, and the MIDAS Plating Guide
even went so far as to say “The rhodium solution is easily
contaminated and care sould be taken not to introduce impurities
such as bare silver, copper, brass, bronze,iron, steel, or any base
white metal”. The consultant is a chemist who has years of practical
experience setting up plating facilities. But isn’t it the case
that not having the nickel barrier on sterling silver will
contaminate my rhodium bath and give me bad color? If I can’t get a
nice silvery color (as white as possible), there is of course no
point in doing it. Does anyone out there successfully do rhodium
plating with really good color on a small scale? Do you get a shiny
nickel pre-plate? Any help in getting a proper set-up and work
sequence would be greatly appreciated!

Thanks.
Janet in Jerusalem

Sorry, I need to run, but I saw your post. You absolutely cannot
plate silver directly in rhodium. The silver sill plate, but the
rhodiuum will be trashed in even one use. You have to preplate -
gold, and then rhodium, is feasable, other than nickel, but the yellow
of gold might gleam through. You have to do something though - you
can’t do it directly, for sure (experience, not book) John D.

Janet,

My experience (long ago) with plating is that it is, in any
situation, a somewhat unpredictable beast. While there is the
standard list of do’s and don’ts (most of which your post indicates
you’re aware of), the mix of equipment, solutions, current levels,
and workpieces often requires “adjustments” to rules and techniques.
Given that you are talking about small pieces, and silver at that, I
would recommend a series of controlled test runs, some with nickle
pre-plate, some not; some high current, some low; etc. Keep notes,
look at the results, and let us know how it all turns out.

Les Brown
L.F.Brown Goldwork, Inc.
17 Second St. East, #101
Kalispell, MT 59901
406-257-1129