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Firing Thick And Large Flat Clay


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#1 StudioEast

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Posted 03 October 2010 - 08:06 AM

I have a project for a flat, 1 inch slab (approx. 30 X 50) I do not know how to set the kiln for bisque.
My first attempt was using 07 cone and slow on my skutt. That actually came out okay.
then I continued to the glaze level and did 5 cone fast. Bad, Bad Bad - the board warped and cracked
on all four sides.

Does anyone have a suggestion how to fire this piece?

#2 Pres

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Posted 03 October 2010 - 09:08 AM

I have a project for a flat, 1 inch slab (approx. 30 X 50) I do not know how to set the kiln for bisque.
My first attempt was using 07 cone and slow on my skutt. That actually came out okay.
then I continued to the glaze level and did 5 cone fast. Bad, Bad Bad - the board warped and cracked
on all four sides.

Does anyone have a suggestion how to fire this piece?


Something like that presents several questions, as there are several problems with it. 1) Is your clay grogged, or are you using fiber to strengthen it, or is it paper clay? 2) How are you shelving the piece to fire, on a single shelf, multiple shelves? 3) Are you grogging the shelf to allow for movement of the clay in heating and cooling? 4) What do you plan for a glaze cycle on the next round? Answering these questions might help you to find your way, or at least to give the good people here a chance to comment.

Simply retired teacher, not dead, living the dream. on and on and. . . . on. . . .                                                                                 http://picworkspottery.blogspot.com/


#3 Marcia Selsor

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Posted 03 October 2010 - 10:27 AM

Fire slower. Robert Arneson took days to fire his pieces.
Also, how are you stacking this. I would use 1/4" coils extruder and set the piece on them (bisque them first). That lets moisture escape from the bottom and lets heat circulate.
You don't want something that massive directly on the shelf.
Marcia

#4 StudioEast

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Posted 06 October 2010 - 11:31 AM

Firstly, the clay is 02 clay - no grog. When I bisque should I put it on coils also? or is stilts enough? My only problem with this firing is that there is nothing else to put in to the kiln at the same time. When I glaze will I do a low fire glaze instead of high? and do I go up slowly as I will in the bisque firing?

#5 Marcia Selsor

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Posted 06 October 2010 - 04:31 PM

I would fire on coils for both bisque and glaze. The moisture can escape the bottom if the piece is on coils.
I learned this from experience.
Marcia

#6 Deb Evans

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Posted 07 October 2010 - 10:24 AM

Just curious - what's it for? Fuction depends on firing temp. What 's the ^ for the clay? Does it need to be vitrified?




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