I'm attempting to transition from fully thrown plates to partially slab constructed to save time and effort. The first iteration of the plates are simple with a flat bottom, no foot, and a short turned up (nearly vertical) side about 3/4-1".
The problem I have is that after the glaze fire the center of the plate has risen up and there's a hump that goes nearly from edge to edge. Before the glaze firing, the greenware and bisqueware plates are flat and look fine.
My process:
Roll the slabs out to about 3/8" thickness
Cut into rough circles by hand
Toss on the wheel and flatten down on a bat
Cut to a perfect circle
While on the wheel, turn the edge up with a wooden tool and my hand
Once it's dry, remove from bat and cleanup any edges with a sponge. Bisque fire flat on kiln shelves, glaze and high fire the same way.
