Posted 01 November 2012 - 11:54 AM
A friend and I share a kiln together. She is having problems with warping in the bisque.
Clay body - Tacoma Clay Art paper clay
firing - ^06 using the Skutt firing schedule
Thickness - 1/4/ to 1/2 ins.
Tossed and rolled with a rolling pin
Design made on drying board
Dried to soft leather hard then: either a second sheetrock board is put in top or weights put on the 4 corners
At leather hard put in a convection oven. on the oven racks and dried for 12 hr at 170 F
Placement in kiln - larger pieces stacked flat on the top shelves, spanned the kiln shelves these had the most warpage
smaller pieces stacked leaning against the shelf
the smaller pieces stacked flat on the bottom shelf seems to have the least warpage
These forums are so great. Thanks for all your help
Posted 01 November 2012 - 01:10 PM
Once flipped, I remove the board and slab mat, attach hanging nubs, wax the edges , slide the sheet rock and slab into my bakers rack covered with plastic and don't move it til it is dry.I bisque them on edge and fire them on edge as well. See photo from Raku Masters at Dan Finch's.. I think you are handling them too much especially before leather hard.
Montana State University-Billings
Charter Member and Past President of Potters Council
Posted 01 November 2012 - 01:12 PM
slow drying under plastic for 1 week plus, skip the oven (never heard of that).. the slower the better
not familiar with that clay body, but that could be a factor...maybe test adding some sand or grog
Posted 01 November 2012 - 04:30 PM
Then don't touch your slab again until it is dry. You can dry it in full sunlight and it won't warp.
Contemporary Fine Colored Porcelain
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