I admit that my attraction to PMC (I’ve never used Art Clay) comes
in part from having started out as a potter. And my metalsmithing
experience doesn’t come close to yours. But I honestly believe that
the major problem with PMC is that people who use it all too often
want instant results, and that the manufacturer has fallen into the
trap of encouraging this mindset.
Most of the problems I have encountered with durability in PMC
pieces result from one simple mistake: under-firing. I would never
follow Mitsubishi’s recommendations for how to fire the newer
versions of the clay. In fact, I find that one of the things I love
best about PMC–how much it shrinks–is lost in the newer versions,
so I have rarely used them. As a potter, I was used to taking
shrinkage into account, and taking advantage of it when designing, so
I don’t see shrinkage as a problem.
I also think it’s possible to join e.g. a bail to a pendant,
strongly, and without solder, if you approach the technique as a
potter will approach attaching a handle to a mug. There is a learning
curve, but people who are willing to accept this fact when it comes
to e.g. soldering, ignore it when approaching PMC.
And the tumbler is PMC’s best friend. Having tumbled both PMC and
fabricated fine silver–to work harden and burnish them–I am not
surprised to learn that Tim McCreight finds that PMC has the density
of cast fine silver. And, as far as I know, most jewelers don’t forge
cast silver pieces, either, so we could always go back to an argument
that casting isn’t “real metalsmithing” any more than PMC is.
(However, I’m surprised that people have trouble filing it. I
originally learned to use traditional finishing techniques–filing
and various flexshaft attachments–on PMC and never encountered
problems. Of course, if you file it carefully before it’s fired, you
often have no reason to file it again. Just like wax!)
But there are at least two issues in this thread, so far. One is
about durability-is PMC durable enough to be used for jewelry, or
will it fall apart? I have some related questions: will well-made
sheet-to-sheet solder joins occasionally fail? I think the answer is
yes. Will poorly-made solder joins frequently fail? Definitely yes.
Can the surface porosity of PMC be overcome with burnishing? In my
experience, yes. Is “underlying” porosity a problem? Why? Can “great"
jewelry” sometimes be made from less than durable materials? I can
only point to millennia of jewelry made from 24K gold.
The other issue has to do with “senselessness” and "offensiveness."
This, dearest Marty, borders on flaming–just because you don’t have
someone in particular in mind, doesn’t mean they won’t feel attacked
by these words. And the discussion of why it does or doesn’t make
sense to use PMC, given the long history of metalsmithing, or how
offended some who feel part of this tradition feel by the use of PMC,
has a long history on Orchid. If there were a way to have a
productive discussion about this, I would be all for it. But I
haven’t seen much evidence that there is. Recent levels of courtesy
on this forum have not been high, so I doubt any current discussion
will be fruitful.
Just my two cents.
Albion, CA, US