Ever torch firing your enamel and it seems like it is taking for evvverrrr! Well there are a couple of reasons, but one I discovered this weekend working with some students in Charlotte. I had my first torch enameling class on Saturday and we were enameling 2" pieces. No problem, the enamel was flowing within seconds! Sunday I'm teaching another torch enameling class with 2" pieces and the enamel is taking forever to flow! What the h@#? Why such a dramatic difference? It wasn't due to the usual influences, bigger piece or not enough heat, those were constant, what could it be? What was the difference? On Saturday we used "transparent" enamel and on Sunday we used "opaque" enamel! That had to be it, so I went to my neighboring artist whom specializes on ceramic glazes etc. and asked his advise. He called an associate that used to work for the company that sold Thompsons Enamel their glass, and he said I was right on! The opaque enamel flows or fuses at a higher temperature than the transparent. The particles that make up the opaque-ness float in the glass like sand floating in the ocean while the particles that make the transparent colors dissolve or saturate in the glass like the salt in the ocean. Therefore, they fuse at different rates, this also accounts for the ability to blend transparent colors and not the opaque colors.
So long story short, if you don't have a large enough torch to get your enamels to flow, maybe by using transparent colors you may be more successful. Just sayin'