StaC,
I just melt bees wax and plaster together on my kitchen stove, because I never use the stove for actual cooking. Ha!
You can play with the ratios. Unfortunately, pitch works the best. Have you tried just using some rubber sheeting, or thick foam? Some people use sand bags. You can pour your mix into a cast iron pan (that works best). I use whatever kitchen pans I have, once again, that cooking thing doesn't happen much. Post your work, I'm still learning a lot myself.
Have fun! Lorrie