Hi Orchid, Some of you may have seen my posts about my problemswith
casting over the past couple of years. So after a lot of research
andtrial and error I seem to have figured it out. The problem
apparently was that my kiln was inadequately vented, which I tried to
fix by drilling a hole in the door and also cracking open the door
when the temp reached around900. I thought that was the thing to do
but what happened is that the wax fumes would ignite, creating a
reducing atmosphere inside the kiln which would reduce the calcium
sulfate to free sulfur. The result was brittle, porous and blackened
castings. So I drilled a couple more holes in the door andstarted
steam dewaxing my flasks before burnout. Since then I’ve had no
problems at all, my castings come out looking almost perfect, they
barely even need pickling. The nasty wax fumes are almost non
existent as well. So thanks for all of your help here. Orchid has
been invaluable in my quest for the perfect casting. All the best,
Doug @ EclipseDesigns in Sitka Alaska