2. Transferring the Image. Now that you have your image transferred onto plastic you can now endeavor to get it onto the clay surface. I like to work with a ceramic surface that is a little beyond leather hard; in fact, I like to call it cheddar "cheese hard". It is somewhere between too late to add a handle, but not too late to make a mark on it with your finger nail. Capisce? Now take a dampened, not drenched, sponge and give the area a quick swipe to create a slightly tacky surface for the...
Although this tutorial is about making vases, it applies equally well to making tumblers. First create a template by wrapping a stiff material around the glass and trimming it to size. Roofing paper works well for making templates for clay handbuilding. Building it over the original glass helps to hold the structure. Baby power can be used instead of a non-stick liquid to help the clay to slide off. Don't forget to add a bottom.