[Jewelry making - Article 00065] - Re: [Orchid] Quick and dirty silver patina?

[Ian W. Wright]

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

    The thing to remember about Chlorine (and several other gases) is
    that in the presence of water (moisture in the air) they form acids.
    In the case of Chlorine the acid is Hydrochloric acid (and/or
    Hydrochlorous acid) and this will react with metals to form their
    Chlorides. Copper Chloride is green, silver chloride is white but
    goes grey on exposure to light. A number of anti-scale compounds and
    drain cleaners contain Hydrochloric acid and so it is always prudent
    to remove jewellery when using these products. Another chemical to be
    very wary of is Ammonia (as in Bleach), this can work its way into
    the grain of metals and then, as it absorbs moisture from the air and
    expands in the confined space, it can literally blow the grains of
    metal apart. This is a particular problem in my field of watch and
    clock repairing where the cleaning solutions used for many years
    contained ammonia. A particular problem known as 'brass
    embrittlement' in which the cast and then hammered brass wheels of
    clocks were literally turning to powder, taxed the brains of the
    scientists for years until it was realised that it was the ammonia
    staying in the microscopic cracks between the grains of metal and
    forcing them apart in a quite spectacular way. 

Best Wishes,
Ian

Ian W. Wright
Sheffield  UK

____________________________________________________________________
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
____________________________________________________________________