18k and sterling jewelry is plating in the pickle!

Jewelry Discussion
1

Has anyone had this problem before? I am using more gold in my
fabricated jewelry. The 18k elements seem to be silver plating
in the pickle after they have been soldered to the silver
elements. The surface of the gold becomes chalky - whitish with
each subsequent heating and pickling. The jewelry is about
equaly weighted with gold and silver, not a small gold part. I
perform four solder operations between the gold and silver
parts. I don’t think I am overheating the piece since I am
using hard silver solder to join the gold and silver parts.

To remedy the problem so far, I have been dipping the finished
pieces in nitric acid. I would prefer not to do this in the
future. Could my pickle be saturated with silver? What do you
all think?

Thanks! Gina Pankowski, Seattle, Washington

2

Gina, I would say that the pickle has very likely become a
plating tank by virtue of the amount of silver that’s been
dissolved in it. Silver dissolves much more readily than gold.
Dispose of the current contents and make up a fresh batch.

Loren Damewood

3

I think you will probably get a lot of responses, most of them
more technical than mine, about what is going on but I will tell
you that I have occasionally seen this happen with my work, but I
have always just been able to buff it off with tripoli. I think
there is some kind of metal transference going on. But it is
usually so light that polishing always resolves the problem.

4 
  To remedy the problem so far, I have been dipping the
finished pieces in nitric acid.  I would prefer not to do this
in the future.  Could my pickle be saturated with silver?  What
do you all think?

Not completely sure what causes it. Something is plating out.
Whether it’s silver of some other metal or effect, I can’t tell.
But I know a simple solution.

Change your pickle.

Peter Rowe

5

It could be as simple as changing your pickle. When I have done a
lot of work with silver then I always use fresh pickle before
pickkling gold.

I don’t know the chemistry of it but I was told by an
experienced jeweller when I was just starting to work with gold.

I hope this helps.
Regards,
Kerry

Kerry McCandlish Jewellery - Celtic and Scottish styles
Commission/Custom Work undertaken…http://www.bennie.demon.co.uk
Katunayake, Creagorry, Isle of Benbecula, HS7 5PG SCOTLAND
Tel: +44 1870-602-677 Fax: +44 1870-602-956 Mobile: +44 850-059-162

6

Gina: In my years of experience I’ve seen this when pickleing
gold & silver pieces together. I would change my solution and
simply not let the pieces stay in the solution quite so long.
Change the solution more often and you should not have any more
trouble. Have you considered using a substitute for sulfuric acid
or Sparex such as alum or perhaps Citrix(sp?)which I’ve heard
about on this list previously. Check the archives for more info.

Steve Klepinger

7 
     I would say that the pickle has very likely become a
plating tank by virtue of the amount of silver that's been
dissolved in it.

G’day; Silver is not very soluble in sulphate solution.
The CRC Handbook of Chemistry and Physics gives the solubility of
silver sulphate as 0.57 grams per 100mls. Having said that, I took
a little of my well-used 10% sulphuric acid pickle and added a
few drops of sodium chloride - table salt - to it. If silver
had been present in the pickle a white precipitate would have
appeared, but there was no change in the pickle colour. This is
a very sensitive test, as silver chloride which would have
formed, is completely insoluble. I performed another test by
adding potassium chromate to the pickle. If silver had been
present I would have seen a deep crimson precipitate of silver
chromate. There was no colour change observed Now you can make
what you like from the above: the academics say that silver
sulphate is 0.57% soluble. Two different actual experiments
produced no reaction. Yer pays yer penny and yer takes yer
choice! Cheers,

       / \
     /  /
   /  /                                
 /  /__| \      @John_Burgess2
(______)

At sunny Nelson NZ

8

John, Ok, good points. AgCl isn’t very soluble, certainly.

Still, there’s something in the solution that is coming out onto
the pieces, and it’s a lot better to dispose of it and start over
if it’s costing time and energy to correct the problem.

It might be that some other metals are getting into the act -
was white gold being used a lot? (grasping at straws here . . .
:wink:

Loren Damewood

9

Thank you for the suggestions relating to my plating problem.
My pickle was very saturated with silver, turning quite milky
with the table salt test that John Burgess suggested. My pickle
solution was over two years in concentration.

A new gold only pickle seems to have solved the problem for
solid 18k pieces. However the pieces that combine 18k and
sterling still seem to be plating in the clean pickle.

If there are any orchid subscribers in New York, please come and
see my new work at the American Craft Museum’s bennifit show -
Gold and Silver 1998, December 3rd - 6th at the American Craft
Museum, 40 West 53rd Street, NY, NY. For more call
212-956-3535. The show is featuring over 60 American and Swedish
jewelers and silver smiths.

Thanks again for the helpful advice.
Gina Pankowski @gpankowski

Original MessageFrom: John Burgess johnb@ts.co.nz
Date: Thursday, November 19, 1998 11:06 PM
Subject: Re: [Orchid] 18k and sterling jewelry is plating in the pickle!

     I would say that the pickle has very likely become a
plating tank by virtue of the amount of silver that's been
dissolved in it.

G’day; Silver is not very soluble in sulphate solution.
The CRC Handbook of Chemistry and Physics gives the solubility of
silver sulphate as 0.57 grams per 100mls. Having said that, I took
a little of my well-used 10% sulphuric acid pickle and added a
few drops of sodium chloride - table salt - to it. If silver
had been present in the pickle a white precipitate would have
appeared, but there was no change in the pickle colour. This is
a very sensitive test, as silver chloride which would have
formed, is completely insoluble. I performed another test by
adding potassium chromate to the pickle. If silver had been
present I would have seen a deep crimson precipitate of silver
chromate. There was no colour change observed Now you can make
what you like from the above: the academics say that silver
sulphate is 0.57% soluble. Two different actual experiments
produced no reaction. Yer pays yer penny and yer takes yer
choice! Cheers,

          / \
        /  /
      /  /
    /  /__| \      johnb@ts.co.nz
   (______)
At sunny  Nelson NZ

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10

– When brass links were put into a tumbler with Kramer 910
tumbling soap, the brass links were uniformly coated with a
grey-black layer. It was so uniform that it looked plated. One
sterling link that was also in the tumbler was unchanged. Any
ideas would be appreciated.

	==Pisces
	@mbm
11

Hi Marion…if you are tumbling brass with ammoniated soap…it
will turn a nasty grey dull color…Try non ammoniated soap I
think Rio Grande or Swest tech people can advise you…Good Luck…
Jana Cooper