[Clayart] re-firing

sumi sumi at herwheel.com
Mon Apr 25 20:46:43 UTC 2022

I have read that re-firing increases the amount of cristobalite, which 
can make a piece more brittle, but also that cristobalite forms above 
cone 6 - so if you fire to cone 6 you're safer refiring. I'm not the big 
expert, maybe others can chime in and correct me if I'm inaccurate.


>> Re-firing
>> I wonder if re-firing makes the pots more brittle that convention would
>> serve?
>> Would a dilatometer measurement of both provide less anecdotal survey?
>> Does cristobalite increase or decrease with that re-fire?
>> Is the pot which has been re-fired more subject to thermal shock?
>> Does it affect glaze fit?
>> Questions surface when we enter a new cave, but light does provide 
>> clarity
>> one hopes.
> Those are all good questions, and I think re-firing does, indeed, 
> change things.
> I don't have any answers, but I think cristobalite is increased in a 
> re-fire, and the
> piece is probably more sensitive to thermal shock and more brittle.
> Just my hunch.
> In my experience glaze fit is not noticeably changed.
> David Hendley
> david at farmpots.com
> www.farmpots.com

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