Rhodium plating 18kt white gold

I have a question regarding plating and am wondering if anyone else
has come across the same problem. This problem seems to only happen
when I rhodium plate 18kt white gold. There are a couple of things
that happen . One is that sometimes I get a whiteish fog on different
spots of the piece and the other is that sometimes I get a redish
spotted discoloration on the piece. I have tried everything to isolate
the problem. I have the piece very clean and use electro cleaner
before plating and I still get the spotting and fogging Any Ideas would be very
helpful… Jeff

Jeff, There are a million variables when it comes to plating.What
type of anode are you using?I use a platinized titanium anode which
has given me years of good results.Do you have a good power
supply?Some people try to plate with batteries or battery
chargers.Spikes in current will change your plating results.Good
rectifiers provide a clean constant supply of DC.What are you hanging
the piece on?I use an alligator clip with a piece of sterling solder
that is bent into a hook.I regularly replace and clean the hooks and
clips.Is your Rhodium solution clean and not played out?I try not to
let the bottom of my solution out of the bottle and try not to shake
the container too much as there is some sediment on solution you have
used quite a bit.Contaminants can affect your plating.How long are you
plating the piece for?On rings I plate it longer one minute +
depending on the piece.How much current do you use?I usually have
bubbles streaming off the piece but not to a boiling roll.And I move
the piece gently as it is plating .Leaving the piece in he solution
the entire time.How clean is the piece?Once the item has been buffed I
clean in an ultra sonic then rinse and steam the piece at that point I
never touch it with my hands as you can actually plate your
fingerprints on the piece.What type of rinse do you use?I always rinse
the piece in cold tap water.Hot water comes from a hot water tank that
usually have sediment in them of some type.The sediment may contain
trace amounts of metal and if there is residual plating solution on
the piece it may react with the it.I managed a commercial jewelry
operation for a couple of years way back when and we compiled these
tips through techs in the trade and trial and error.You can also call
the companies that manufacture plating solutions most of them have
techs that are more than happy to give assistance.Hope this helps.Best
J Morley CoyoteRidge Studio Where the snow is fallin and my snowboard
is workin