[Jewelry making - Article 00286] - Re: [Orchid] Accidental Copper Plated Gold

[Gary]

========[ Invite a Friend - http://www.ganoksin.com/invite.htm  ]========

    This is almost certainly the result of two things: the pickle has
    dissolved some copper as a result of being used for some time (it
    probably looks slightly blue), and you accidentally immersed some
    iron with the gold pieces (possibly a steel spring in a clasp, or a
    steel jump-ring). Fresh pickle won't do this, even in the presence of
    iron. 

    I once made some complicated earrings out of white gold chenier.
    Since the chenier had to be bent to quite a small radius I originally
    made it with a copper core that I thought could be dissolved with 10%
    sulphuric acid, but it didn't work; the copper appeared untouched
    even after a day or so. 

    Although I'd read previously that a core of soft iron was
    recommended I was also aware of the problem of iron causing the
    copper to be deposited, so I tried an experiment; I left a loop or
    two of the copper filled chenier in the acid and dropped an iron nail
    in too. The iron fizzed a bit, but after several hours there was no
    visible copper on the gold and the nail was visibly attacked so I
    remade the chenier on a soft iron core and put it the acid again.
    This time it worked; the iron was dissolved OK (took a day or so),
    but to my surprise, the white gold got plated with copper. 

    From this I learned that the iron *has* to touch the gold for the
    copper to be deposited. This would explain why one item was plated
    and the other not; the one that was plated was touching the iron. 

    I found that 30% nitric acid removed the copper in a few seconds. I
    put the acid in a small jar, took it outside into the garden,
    suspended the earrings on a bit of nylon cord, and dipped them in.
    They fizzed like a Selzer tablet for a few seconds, and when it
    stopped I removed them - the copper was gone. I thought the nylon
    wouldn't be affected by the acid, but I was wrong. A few minutes
    later the nylon just broke - but it had already done its job. 

I hope this helps.
Regards, Gary Wooding
____________________________________________________________________
T h e   O r c h i d   L i s t
Open Electronic Forum for Jewelry Manufacturing Methods and Procedures
____________________________________________________________________
Orchid FAQ:
~ http://www.ganoksin.com/orchid/faq.htm
Orchid Archives:
~ http://www.ganoksin.com/orchid/archive
Orchid Galleries:
~ http://www.ganoksin.com/orchid/gallery.htm
Invite a Friend:
~ http://www.ganoksin.com/invite.htm
____________________________________________________________________
Tips From The Jeweler's Bench - Article Archive
~ http://www.ganoksin.com/borisat/tip_sear.htm
The Jeweler's Selected Bibliography List
~ http://www.ganoksin.com/jewelry-books
Buy Orchid Jewelry:
~ http://www.ganoksin.com/shop
____________________________________________________________________
-Unsubscribe:
-Email: orchid-request AT ganoksin.com Body=unsubscribe subject=blank
____________________________________________________________________