Daily Archives: August 18, 2009

The Question is:

Do holes shrink?

In my metal clay world the answer is yes and no. How can that be? I read in one of my books, (but I’ll be darned if I can find the quote or source) that since a hole is a void, there is nothing there to shrink or grow. So how can a “nothing” shrink? But, when making a ring out of PMC, one must account for the shrinkage of the clay to insure a proper finished size. In that instance the hole in the middle of the ring actually does get smaller. It shrinks. But when I drill a hole in unfired clay, to accommodate an ear wire, the drilled hole does not shrink when its fired.  You would  think that the hole would get larger as the clay shrunk in on itself, pulling away from the hole. But that little drilled hole stays the same size. The same with these earring and necklace components. I used a cutter to take make a hole in the flat bead. The cut out piece shrunk, the larger earring piece shrunk, but the hole stayed the same size that it was before firing.

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A bezel made of PMC will shrink during firing, but the hole I cut to set the moonstone  below, stayed the same size. I think I need some physics to understand this.

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