It's never been necessary for me to go much higher than the conversion
temperature of the clay.
Of course, this is going to vary, depending on the formula, the amount
of grog, etc.
Your altitude and your humidity level are going to make a difference
too, but here at sea level,
it works for me. Saves on energy ($), and cooling time, both
important considerations for production work.

Wayne
Key West



Hello Wayne

Your answer is worth heaps. We trend to take what is written down as
gospel without testing it ourselves. I am working with a white stoneware
clay that matures at cone 6. Possibly has a frit of some sort in it. When
you think about it there probably isn't a great deal to burn out after it
reaches the conversion temperature. I have been firing bisque to 1000c
because that is what I was told I had to do

The only question is What adjustments have you made to your glazes?

Regards

John Webb