Rhodium plating anomaly

i recently recieved a platinum/ reuthinium casting from my trusted
and long time supplier which after the diamonds were set and final
polish revealed a pit! so… filled the pit with palladium white
gold solder so as not to burn diamonds plus achieve maximum color
similarity. slight color variation on the fill so i decide to rhodium
plate. results? rhodium will not stick! NOW much to my frustration
the rhodium sticks to everything else i plate spotless and perfect
before and after along with or whatever. my rhodium only does not
stick to this one piece. rhodium is somthing ive been doing for years
i do it with no second thought even solved many other problems but
this one has me stumped there is somthing about this one particular
ring, i have inquired to the supplier of the casting who has basicly
said look for someone else, a professional, to plate it. i thought my
years of successfull plating qualifed me as such but now im not so
sure, anyhow, i humbly submit my anomolous situation to the list and
submitfully accept any and add all suggestions as to why my
previously successfull methods have failed

best regards -goo

Hello Goo;

I’ll take a guess at this. The rhodium plating is not appreciably
whiter than the platinum, so maybe it’s there but it isn’t obvious
because you can still see the palladium solder, which, although it
is also being plated, appears to be a different color because, in
reality, it has a difference surface quality and is reflecting the
light differently. Maybe burnishing would help. That failing, I’d
bur out the solder and get someone with a laser to fill the pit, then
forget the plating.

David L. Huffman

You can not not Plate Palladium. I use 1500 Plat solder on
Palladium. No line.

Johneric

i recently recieved a platinum/ reuthinium casting from my trusted 

This is a proper spelling for Ruthenium. No offence, just
clarification

Danuta

Goo,

We have the same problem sometimes. We will rhodium dozens of things
without a problem, them one just will not plate well, then another
dozen plate beautifully. I have always chalked that up to mysterious
alloys. We will polish and rerhodium the crappy looking ring, but it
will look spotty or dark and undeliverable. Our only recourse is to
replace the rhodium with fresh and try that. The new rhodium usually
works, but it bugs me to do that because I feel like I may be
contaminating perfectly good rhodium with something weird in the
ring that wouldn’t plate well.

I will state our rhodium plating procedures just in case it might
help you.

  1. Polish
  2. Clean ring in ultrasonic (distilled water in ultrasonic)
  3. Steam clean (distilled water in steam cleaner)
  4. Electroclean (made with distilled water and Gesswein’s electro
    cleaner powder, heated to whatever they say to heat it to, I’ve
    forgotten).
  5. Dip to clean in distilled water.
  6. Electroplate with rhodium (3 volts, about 20 seconds, 3 gram
    solution)
  7. Dip in distilled water
  8. Steam clean

It is weird that your ring would not plate. I don’t think the solder
had anything to do with it. And although it’s unnecessary to plate
platinum, it rhodium plates beautifully. I think it’s just one of
those mysteries that makes life interesting, and a pain in the ass,
usually in equal measures in my life. We would laser the area you
soldered, you should buy a laser Goo.

Mark

Mark - well i am sorry to know you have problems w/ plating from
time to time but also i am glad to have company at the same time. i
do basiclly the same procedure as yourself .

ive usually found the spotting to be soved by replenishing my
soloution then everything works fine. the 14k palladium/white gold
solder from pm west was used because i did not want to burn the
diamonds using a high temp plat solder. i plat the high pd white gold
and have no problems and plat with no problem. do you think there
could be an oxide that is forming on the surface of the metal ? maybe
somthing that has a similar nature to the oxide that forms on
aluminum?

later goo

Goo

i plat the high pd white gold and have no problems and plat with
no problem. do you think there could be an oxide that is forming
on the surface of the metal ? maybe something that has a similar
nature to the oxide that forms on aluminum? 

I don’t know why you would have a problem when using pd white gold in
combination with platinum. I wouldn’t think you should have any
unusual oxidation. Even if there was, it should have been removed
during the polishing process, and everything should rhodium plate
just fine. Micro pitting would make it appear like it wasn’t plating,
but you would have noticed that. I’m stumped.

Mark