As I mentioned in an earlier post, I headed down to Eugene–my first trip to Eugene, by the way–for a PMC class from goldsmith-and-PMC-expert Carolyn Scott Kent.
PMC, or “precious metal clay,” is basically ground-up metal in an organic binder, so you can shape it, fire it, polish it up…and have a nice piece of jewelry or whatnot. Our 2-day class (well, 4 hours each on Saturday and Sunday) was all about using the fine silver version of this stuff, PMC3.
PMC3 is a heavy (REALLY heavy) whitish clay with a texture reminiscent of a less-rubbery silly putty. It’s a bit of challenge to work, as I discovered on the first day, but compared to the skills needed to develop similar work through silver casting and forming, it’s amazing. On Saturday we formed our pieces (silver dollar-sized pendants, mostly), dried them on a simple hot plate, and cleaned up the dried clay.
You do that by continuing to carve it, sanding off the pointy parts, and burnishing the clay flat and smooth. We finished out the day by embedding our work in very fine alumina hydrate, on a kilnshelf, and firing.
That’s what mine looked like when they came out, and not all that different from their appearance going INTO the kiln. If you look closely you can see glints of metallic gleams in the otherwise white matte finish. It’s easy enough to remove; our kits contained a brass brush that brought up a satiny silver finish in 4-5 swipes.
After that we applied sandpaper in various grits, diamond files and more brass-brushing to get to a finish we liked. Some burnished their pieces for a high shine (left).
Me, I liked the texture too much to burnish the whole thing. If I’d wanted a high shine, I could have brought it home to my ultrasonic tumbler and gotten a uniform gloss.
The primitive, hand-made charm of these pieces (a polite way of saying “crude”) would be lost with a lot of shine, though, so I opted for a softer finish. Took about ten minutes per piece, tops, with sandpaper and brush.
Carolyn had brought along a few rocks of liver of sulfur, a patina that dissolves in hot water and blackens (or browns, depending on the strength) silver. You dip your cleaned and shined-up piece into it, let it sit for a few minutes, and it comes out a nice blue-black, like this:
The black, in turn, is pretty easy to rub/brush/sand off the high spots, but tends to stick in the crevices. In my case, I wanted the textures I’d added to the clay to stand out, and so I left a fair amount in the low spots:
The little stacked-star pendant has possibilities. Not so sure about the chains–they were fun to make but would be the world’s heaviest dangle earrings because solid silver isn’t exactly lightweight.
To be honest, they’ll probably end up being recycled into something else. I’ll add a jump ring and a chain to the stars, though. My fellow students, to be honest, came away with more impressive pieces. This was Jo Ann Syron’s, for example.
On the whole, I’m intrigued by PMC, and anxious to see what it can do once I get the measure of it. I sense another expensive hobby coming on. 😉