Paul B on fri 3 jun 05
I recently changed my firing schedule from ^10-11 to ^11-12, mainly because
i found that to get ^11 anywhere past 3:00 at the top means getting ^11
down flat on the bottom which means ^12 can't be too far away if it's not
there already. The glazes all seem to come out just right throughout the
kiln at this point, but any bowls on the bottom come out warped so the body
must be overfired down there.
Basically i just need to adjust the following body to make it suitable for
^12:
EPK 35
OM-4 25
HAWTHORNE BOND 25
200M SILICA 5
G-200 10
MULLITE GROG 10
Anyone have some advice on how to best do this?
thanks,
Paul
Michael Wendt on sun 5 jun 05
Paul,
try replacing some of the OM4 ball clay with Helmer or EPK. Either is more
refractory, a little coarser and thus less prone to warping. Check also for
subtle setting imperfections that might account for the warping. I use
saggars made from insulating fire bricks to protect large bowls and sinks
from uneven heating and cooling that can cause warping.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave
Lewiston, Idaho 83501
USA
wendtpot@lewiston.com
www.wendtpottery.com
Paul wrote:
I recently changed my firing schedule from ^10-11 to ^11-12, mainly because
i found that to get ^11 anywhere past 3:00 at the top means getting ^11
down flat on the bottom which means ^12 can't be too far away if it's not
there already. The glazes all seem to come out just right throughout the
kiln at this point, but any bowls on the bottom come out warped so the body
must be overfired down there.
Basically i just need to adjust the following body to make it suitable for
^12:
EPK 35
OM-4 25
HAWTHORNE BOND 25
200M SILICA 5
G-200 10
MULLITE GROG 10
Anyone have some advice on how to best do this?
thanks,
Paul
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