Cone 6 clay and cone 7 & 8 glaze

[Teabrook]

Good morning!

I have just purchased cone 6 clay. A pallet full.

and my glazes are cone 7-8.

Any predictions if i fire to cone 6?

Not sure if I should do a test fire fire and see, or whether I should take a chance.

Any advice please?

[Bill Kielb]

Test for sure, no reason not to. Cone 7/8 glazes interesting! Are they commercial and advertised as maturing at cone 7/8? If they are not commercial and simply formulas tested to cone 7/8 then it would be interesting to see the formulas.  If your cone 7/8 glazes fired to cone 6 have the expected surface melt then a little durability testing could give you confidence they are good at cone 6, else firing cone six with a 15-20 minute hold could provide somewhat of a solution.

[Teabrook]

Thank you Bill. They are commercial glazed. I will do some test tiles and a hold at the end and see how i go.

[Bill Kielb]

Have you fired them to cone 6 in the past?

[Jeff Longtin]

More than likely your clay body will have an easier time going to 7 or 8 rather than dropping your glaze temp. 

I'm working with a "cone 6" porcelain casting slip and it easily handles cone 8.  The cone 5-6 glazes handle it, as well, BUT they move a little bit more and matte glazes did develop a slight sheen.