I'm having trouble with cracks forming at the edge of big (14 inches in diameter, that's big for me!) hand-built dishes while they are drying. Even thickness, about 1//4 to 1/3 inch, with an added foot ring slightly thicker. Formed from a slab, with a pattern pressed in from a basketball net, draped over a bowl covered in T-shirt material or over a pillow made from a stretchy material with polystyrene beads inside. I gently ruffle the edges, i.e. 6 ups and 6 downs on the perimeter. Clear?
I drape a lightweight cloth over it and then drape plastic over that and leave it for a couple of days. Once it's dry enough to turn over, I do that, and continue to keep it all covered. Still, the edges get completely dry while the center stays damp, and then a crack forms. Of course! In both cases, the crack came where the lines had been incised, so now I'm trying with no lines near the edge.
If this one cracks, I'm in trouble! I've promised it for a charity auction, to go with a smaller piece. made the same way, but deeper. That one didn't crack!
I can't figure out how to get the center to dry more quickly, to keep up with the edges. Should I use a heat gun on the foot ring and center? Or should I spritz the edges frequently until the center catches up??
Ideas, potter friends & helpers? I'll try to post 2 photos. One of the last one with a clothes pin next to one of the cracks (not bisqued) and the other of the current one, made yesterday, draped over the pillow thing.