[Clayart] re-firing

vpitelka at dtccom.net vpitelka at dtccom.net
Wed Apr 27 19:52:40 UTC 2022

Barry's original post does not specifically say what the specific refiring circumstance is, thus the range of responses bouncing between the sensible and the fanciful.  In the general ceramics conversation, when people talk about refiring a glaze-fired piece, they are usually referring to a circumstance where they are unhappy with the glaze and want to improve it by firing it again to the same temperature.  In some cases, as in Mel's recent refiring, it comes out great.  In other cases, it can ruin the work.  

This is what I found to be true through 50 years of full-time professional experience in studio clay.  If you fire a midrange or highfire claybody to the high end of it's firing range, for example, a cone 8-11 claybody fired to cone-11, and then fire it to cone-11 a second time to "improve the glaze outcome," you have effectively increased the duration of the firing and pushed the claybody at least to cone-12.  The effect may be slight, but it will be more brittle and will have lower thermal-shock resistance.  

This has nothing to do with the firing protocol employed by Ron Nagle, Ralph Bacerra, Adrian Saxe, and many others.  Additional firings at progressively lower-temperatures for additional glaze, china paint, and luster effects are an entirely different matter and would have no undesirable effect on the durability of the claybody.  Multiple firings of claybodies specifically designed to be as refractory and thermal-shock-resistant as possible, as in bricks and kiln shelves, would have no undesirable effect.  

I hope that clarifies things.
- Vince

Vince Pitelka
Potter, Writer, Teacher
Chapel Hill, NC
vpitelka at dtccom.net

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