[Jewelry making - Article 00349] - Re: [Orchid] Organic oxidyzer for copper?

[Peter W . Rowe]

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


>     It is as if the layer of  contamination somehow reacts with the
>     carbon, which seems to suck it up or something. 

    Or it could be simpler.  Try this one.  contaminate your silver to
    copper plate it the same way, then, without flux or other covering,
    anneal it.  Now pickle it in the same strong pickle.  I'll bet your
    copper will also be gone this way. 

    Heating the silver enough to carbonize the jam will also allow the
    copper to oxidize, and the copper oxide layer thus formed would
    quickly pickle off. the carbon you put down is porous enough that it
    will easily let atmosphere through, and i doubt you were hot enough
    for the carbon to be actively scavenging the oxygen from the copper. 

    Also, as you heat, the very thin layer of copper will at least
    partially start to dissipate into the silver, again giving the
    appearance of cleaning it off after pickling. 

    And, since you say you're using really strong fresh pickle, allow me
    to point out that metallic copper, not just copper oxide, is attacked
    by sulphuric acid, and since your pickle is a sulphuric acid salt, 
    your pickle will also slowly attack the copper.   So try this one
    too.  Again contaminate a piece of silver with copper.  This time,
    without additional heating or anything,  pickle it in new, strong,
    sparex solution.  See how long it takes for the copper to just be
    dissolved off by the pickle itself without any other mechanism.  

    I'd guess the only thing the jam might do is provide at least a
    little bit of protection against fire scale, since the amount of
    oxygen getting to the silver surface will be reduced, and of course
    the copper on the surface will tend to react with that before the
    oxygen gets down into the copper alloyed with the silver.  Whether
    it's a measurable degree of protection or not, might be an
    interesting experiment, since if so, there are other easier ways to
    apply a carbon coating.  Any acetylene flame, without enough
    air/oxygen to burn cleanly, will leave soot (carbon) on any surface
    it's applied to.  So if you find a carbon layer appreciably reduces
    fire scale or fire stain, or some such, then if you're working with,
    say, a prestolite type (air/acetyelene) torch, then it might be
    possible to just soot up the piece by covering the air intakes on
    the torch tip, before heating.    On the other hand, perhaps the jam
    IS needed for this, since it would also supply organic binders that
    might help bind the forming carbon to the surface, or in burning the
    jam to form the carbon, perhaps additional beneficial activity
    occurs, much as it seems to when we use an organic glue binder in
    granulation.  It might increase the protection afforded by the carbon
    alone, or it might just help hold the carbon in place.  Who knows. 

    Might be worth playing around with, however. 

Have fun.
Peter


____________________________________________________________________
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
____________________________________________________________________