Megan Ratchford on tue 19 nov 02
Hello list!
It has been mentioned to me that warping of the ware during a glaze =
firing is linked not to drying of the pieces or clay memory, but is in =
fact linked to firing the ware too fast in the glaze firing. (?)
Now I fire the kiln (a fifty cubic foot downdraft car kiln) over a =
12 to 15 hour range in a moderate reduction. I candle the kiln =
overnight and it is at 300 deg F when I get there at 3:30 am to start =
the kiln. I put the two burners on low with the blowers on low till the =
kiln is at 1400 deg (about 7 am.) I turn the gas to full and the =
blowers to almost half. I keep a bit of back pressure till 1800 when I =
set the blowers to 1/3 and set the damper to allow body reduction (about =
9 am.) At 1940 deg(about 10 am) I pull out the damper enough to keep a =
slight reduction. I keep the kiln in this reduction till cone 9 begins =
to tip (about 2-3 pm) and then go into a little heavier reduction for =
the glaze. When cone 9 is down and cone 10 is soft (about 4-6 pm) I =
open the damper and re-oxidize the atmosphere. I then shut down the gas =
and blowers and allow the kiln to cool to 1700 deg when I close it up to =
cool slowly the rest of the way.=20
So, what is warping? Is it when the ware is handled when wet, =
during the drying, while the pieces are firing in reduction, or when I =
cool?
Also, is this firing too fast???
I would love some input on this, as a friendly brawl is brewing!!!
Megan
In sunny Colorado wondering where the snow has gone...
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