Saturday, February 17, 2007

PMC Progress

A couple friends have asked about the process I go through when making a piece with Precious Metal Clay (PMC), so I took a shot of a few pieces on which I'm currently working. The three sets of items on the left are made with Standard PMC (also called Original) .. it's water content is a bit higher than PMC+ or PMC3; and so once fired, these pieces will shrink about 28% (which makes my head spin when I'm trying to think about how large or small I want the piece to be once fired). I've been working on these items with files and consecutively finer sanding papers, which is why they look a little more "finished". I had to repair a break in the leaf, and so have a bit more sanding to do on it before putting them all in the kiln. Original PMC gets to bake at 1650 degrees for a couple hours. The two sets of items at the top will be earrings, the leaf a pendant.

The rougher-looking pieces on the right are impressed with a design and then hand cut from PMC3. I haven't yet done anything to them but impress and cut them. I have a warming plate on which just-cut pieces set to dry .. doesn't take very long this way. If there's any moisture left in a piece when put in the kiln, it will crack. Occasionally, I'll just let them dry naturally for a day or two. If you don't keep an eye on them while they're drying on the warming plate, they may curl up on you. A problem that can be fixed in a couple different ways .. but it's better not to have the problem.

The PMC3 pieces are slated for a bracelet. The piece with an additional hole in the center will be one part of a toggle clasp. I haven't yet cut the bar that will go through it. Since PMC3 has less water content, it dries out a lot faster while you're working with it .. you really have to know exactly what you're going to do, have all your tools and devices out and ready to grab, and get down to it .. quickly. I just wasn't quick enough to get that last piece cut .. as it was, the remaining PMC3 scraps were beginning to crack. I added some moisture to the mass of scrap, massaged it a bit between a piece of plastic wrap, and shut it up tight in it's original zip bag (and then put THAT into a glass jar with the lid on tight). Hope to get back to it today .. the PMC3 scraps should be a bit more pliable now after a day or so of "moisture management".

Additionally, I'll have to enlarge the holes a bit .. wasn't thinking when I made them. If the holes are not large enough, the 20 or 18 gauge wire with which I hope to connect the segments won't fit through. Easier to enlarge holes in this stage, when they're still just dried clay. I could also do it once the pieces are fired, but it's a lot more work to enlarge holes in fine silver than in dried clay! I'll also need to tidy up all the edges .. you can also see from the pic that a couple of the pieces did indeed curl up a little on the corners. I'll have to address that once they're fired. It won't be too much work to straighten them out with a rawhide hammer .. fine silver is usually pretty soft. It's difficult to see from the pic (I set up the camera real quick), but the impression came from a rubber stamp full of musical staves and notes. Upon reflection (hind sight is a wonderful thing), I probably should have cut the pieces on the diagonal .. for more visual interest. But it'll be fine ... next time perhaps. Maybe for a matching pendant!!

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