Testing Cone Levels -- A question.

[Rick Wise]

A question:

I want to run a test of what a particular clay/glaze combo looks like at various cone levels -- for instance, cones 5, 6 and 7. 

Can I fire a single piece at Cone 5, let it cool, examine it, then place it back in the kiln, fire it to Cone 6, let it cool, examine it, then fire it to Cone 7?  If I do that will I see results just as if I had fired each of 3 different pieces to just one of the cone levels I want to test?   Or do the repeated firings have a cumulative effect?

[liambesaw]

There's a cumulative effect.

[Bill Kielb]

4 hours ago, Rick Wise said:

A question:

I want to run a test of what a particular clay/glaze combo looks like at various cone levels -- for instance, cones 5, 6 and 7. 

Can I fire a single piece at Cone 5, let it cool, examine it, then place it back in the kiln, fire it to Cone 6, let it cool, examine it, then fire it to Cone 7?  If I do that will I see results just as if I had fired each of 3 different pieces to just one of the cone levels I want to test?   Or do the repeated firings have a cumulative effect?

Yeah, since the first firing consumes most of the melting of the claybody and glaze, usually subsequent firings stress the ware Because most of the quartz and alumina have melted and matured to some point. It would be a fascinating experiment but likely would not accurately be indicative of a single fire of the glaze.
What most do is simply fire individual test tiles to 5,6,7. When we create a glaze my final step is to fire at varying temperatures so I have an idea of the working range of the glaze.

[Mark C.]

The glaze will just get more fluxed with each fire. It can run off the test the second or third fire-better to make thr3e tests and fire each to the different temperature. Thats a true test .

[Chilly]

Make 3 separate, separately fired test pieces.  Then you can compare them side-by-side when done, and not have to rely on memory/over/under exposed/out of focus photos.