Laurie Cowell on mon 7 mar 05
Question regarding bisque temperature for pots being firing in Cone 20
reduction. One person I know insists on Cone 04 in order to "remove
impurities". Everyone else I know fires to Cone 06, but I believe
somewhere in the past I read that Mel goes to Cone 08. Any comments from
folk would be welcome.
Laurie Cowell
Vince Pitelka on mon 7 mar 05
> Question regarding bisque temperature for pots being firing in Cone 20
> reduction. One person I know insists on Cone 04 in order to "remove
> impurities". Everyone else I know fires to Cone 06, but I believe
> somewhere in the past I read that Mel goes to Cone 08. Any comments from
> folk would be welcome.
Laurie -
I guess the easy answer would be that it doesn't matter what temperature you
bisque to, because at cone 20 your pots are all going to melt anyway.
Sorry, I couldn't resist. I know you meant to write cone 10. At the Craft
Center we always bisque to cone 08. I like the combination of durability
and porosity, so that you can handle the wares without worrying about them
breaking, and yet they will take a good coat of glaze. If you bisque to
cone 06 or 04 the wares will be even more durable after the bisque firing,
but less porous, and the glazes must be mixed thicker. I have always
achieved best results with a cone 08 bisque. That's been my preference for
35 years.
The manufacturers of commercial low-fire glazes generally recommend an 04
bisque, because the glazes contain brushing medium and binders, and rely
less on the porosity of the clay. But for any glazing process where you are
dipping, pouring, or spraying a glaze that is made of just powdered glaze
materials suspended in water, the porosity of a lower-temperature bisque is
essential.
Good luck -
- Vince
Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
Steve Irvine on mon 7 mar 05
Laurie,
I've always done my bisque at 09 or 08, usually reaching temperature in about 6 hours. Vince
gives a good summary in his posting of the thinking for different bisque temps.
Some potters are very particular about the bisque temp, and yet I can think of one well established
potter who simply fires to "orange" for his bisques. Try a few different bisque temperatures and
see what is optimal for your work.
Steve Irvine
http://www.steveirvine.com
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