Art Clay

Jewelry Discussion
1

Dear Dr. Aspler,

I read with interest a recent message about Art Clay, a product
similar to Precious Metal Clay (PMC) that was developled in Japan
and has been the subject of a patent suit there for several years.
In response to the questions I’ve received, I’d like to pass along
what I know so far.

  1. The material is a lot like PMC with some qualifications. For one
    thing, I found it stickier and consequently less appealing to
    handle than precious metal clay.

  2. The firing is a little fussier, at least as described in the
    paper that came packaged in the material I bought from Swest.
    Basically they advise to dry the pieces overnight, then bring to
    800 degrees C over the course of an hour and hold at that temp. for
    30 minutes. This is not significantly different than the
    recommended process for firing PMC (900 degrees C for two hours.) I
    have heard mention of a firing time of ten minutes. This is not
    described anywhere in the printed material that came with Art
    Clay. It is possible to fire PMC for 10 minutes too. The result
    looks like metal and can be polished, but it is so weak it can be
    broken in the fingers. This is so obviously unacceptable that we
    don’t mention it in the literature.

  3. Shrinkage of Art Clay is less, but so is density. I sent a
    sample to the lab in Japan and they confirmed that it is about 5%
    less dense. That is, where PMC is 80% as dense as rolled metal, Art
    Clay is 75% as dense.

  4. Art Clay costs about 20-30% more than PMC. It shrinks less, but
    not enough to offset this higher cost. Or to say it another way, a
    dollar of PMC will make a bigger piece than a dollar of Art Clay.

  5. I was disappointed with the printed material I got from Swest;
    obviously a piece translated in Japan. I don’t think their support
    approaches the combined efforts of Rio Grande and Mitsubishi as
    shown in a video, web site, newsletter, Masters Classes, research
    support and teaching support.

Because the matter is under litigation, Mitsubishi’s position will
be to watch with interest but take no aggressive action.

Thanks for keeping me informed,

Tim