Ideal surfaces for the encaustic medium are rigid and absorbant. Rigid, because you want your wax to have a stable surface to avoid cracking and chipping, especially on highly textured and dimensional art work. Absorbent, because it is important for the initial wax layers to bond to the surface. For this reason, it is very important that you do not use a typical acrylic gesso as a painting surface. The freezer test will help you identify whether the support you are working on is acceptable or not. Simply paint and fuse a test strip of encaustic paint to your support of choice and then place in the freezer till thoroughly chilled. Take the test panel out of the freezer and give a good swift whack against something hard, like a cement sidewalk. Look for wax shearing off the surface cleanly. The idea is to see if the wax will chip off. If it does then chances are you do not have a suitable substrate. Remember, this is just a guideline, you are the artist. Even though highly flexible, we have also used many different papers with great success, especially Japanese and Printmaking papers. Very absorbent and wax bonds well.