From cone 10 to cone 6

I read that you can substitute potash feldspar for NephSy feldspar (maybe add 10% Gerstley) and this will allow you to turn almost any cone 10 recipe into a cone 6 recipe. Has anyone tried this or have comment?

Comments

Lori Watts saidā€¦
I have replaced half the feldspar in some Cone 10 glazes to bring the firing temp down to Cone 8. That worked fine.
John Britt saidā€¦
The nepheline syenite for Custer will sometimes work but... that and ....adding 10 % frit or GB will work, usually. Still have to test and it isn't the same glaze anymore because of more sodium and more boron.
Melissa Rohrer saidā€¦
I have a recipe written for both cones 8-10 reduction and cone 6 oxidation. To change to cone 6 it makes a direct substitution of Neph Sy for Custer feldspar.
Diane Puckett saidā€¦
My concern with making substitutions is that I may transform a food-safe glaze into one that is not. I am sure Britt covered that in Glaze Boot Camp For Masochists, but my brain had shut down by then.