[Jewelry making - Article 00284] - Re: [Orchid] Article: Minimal Metalsmithing

[James Binnion]

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>     Actually it is not. MDF and wood are not the same thing. PMC is
>     fine silver and fine silver is fine silver. 

    It is an excellent analogy wood is ground up to make MDF and silver
    is atomized to make PMC they both have a binder to hold them
    together while in paste form and the only difference is one uses a
    polymerization to keep it together the other uses diffusion. They
    both lack the mechanical properties of the parent material. 

>     I repeat, PMC+ when fired at 1650 for 2 hours has the same density
>     as cast fine silver. 

    BS, there is no way to get near cast density from powdered metal
    products without lots of pressure either by Hot Isostatic Press
    (HIP) or some other form of hot press process. Who ever told you that
    is just plain wrong. Do a little research on powder metallurgy. 

    There is nothing intrinsically wrong with powdered metal products
    when processed correctly. Powdered metals processes are a low cost
    way to mass produce net or near net shape parts with appropriate
    physical properties for their intended use. There are powdered metal
    products that have properties that would be difficult if not
    impossible to achieve in other forms of manufacturing. But these are
    all highly engineered industrial products. PMC lacks strength and
    density because it is not compacted before sintering and is not hot
    pressed or post sintering HIPed. So it is not the material but the
    processing. And unfortunately the proper processing is beyond studio
    metalsmithing capabilities and pocketbook. 

Jim

James Binnion
jbin AT mokume-gane.com
James Binnion Metal Arts
http://www.mokume-gane.com
360-756-6550
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