I have tested most of the local stoneware clays and discovered that they are vitrified at cone 6 - so why not? Colours are better, there is less wear and tear on the kiln and less stress for the clay.
But a few months ago I have got a challenge: Lower the firing temperatures for the Belmont Potters Group.
The Group has been talking about it on and off for years, but it could not quite make the decision to "jump" into it.
The biggest stumbling stone: What shall we do with all the Stoneware glazes?
So first thing that we did was to fire all available glazes to the cone 6 (1220oC)