HOW TO calculate shrinkage

X – (S X) = Y

Initial dimension – shrinkage percent times initial dimension = final dimension

So if your clay shrinks at a 14% rate, your formula would read X – 0.14x = Y or 0.86 x = y.

Most boxes of clay have the shrinkage rate marked on them. If you are still not finding it, check the website of the Company you purchased the clay from.

The photo above is one of my favorite ways to figure out the size to make a finished hole. First get yourself a plastic Circle Drawing Template. You can purchase them at craft or office supply stores for around $5. Slab out the clay that you will be using for your project. Don’t get your clay too thin or it will be fragile. Set the plastic template on top of your slabbed out clay and using your pin-tool trace all the circles. Make sure you are pressing the pin-tool all the way through the clay so the circles come out easily. If you are having trouble try letting the slab firm up a little bit, but not too much. When you are finished removing all the holes let it dry completely, flipping every so often to keep it from warping. Let this dry completely. When it is completely dry put it into a glaze firing (you do NOT have to bisque this). Even though you did not glaze this it still needs to go into a glaze firing to get it to shrink to the correct size. When it is all done you can use your ceramic template to figure the size that you need for the finished piece, then match it with the plastic template so you know how large to make it at the greenware stage.