[Jewelry making - Article 00438] - Re: [Orchid] 18k white gold casting problems

[David L. Huffman]

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


>         Dear All, In the last year we have begun to experience some
>     difficulties casting our 18k white gold projects. 

    Hi Brenda; It sounds to me like an effect I've seen when white gold
    is overheated in an electric melter with a graphite crucible.  When
    you look at the casting under magnification, can you see dendritic
    structures?  Those would look like tiny, short, straight lines
    pointing in all directions.  This is carbon attempting to form
    branching crystals within the grain boundaries of the metal.  You
    might note a bit of glassy hardness where those little hairs are
    concentrated.  If that's the case, what may be happening is that
    your electromelt needs to be calibrated, as the temperature inside is
    higher than what the pyrometer is reading.  Don't know how you would
    do that for your perticular melter, but you might get info on that
    from MPG repair (who post here on the forum). 

David L. Huffman


____________________________________________________________________
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
____________________________________________________________________