Expert: Sam Kelly - 9/18/2009

Question
We have recently made tiles 3/4" thick and 16 x 16 sq., with slab design added on top.Stoneware cone5/6 clay.  We were wondering how the best way to fire to bisque would be, to keep from warping or cracking. We dried slowly for 4 wks.and didn't move until completely dry to sit on racks. Will leaning against each other cause warping, and should we fire hot just once with small amounts of glaze added to greenware? Will they dry better laying down with glaze? We won't be glazing edges, these are for outside, hot weather, little rain.  Thanks.

Answer
Hi, at that thickness firing to bisque on thier sides should not be a problem. Tiles are best made on a slab roller or made in a cast with casting slip. warpage during drying can be eliminated by drying between 2 flat surfaces with a weight on the top surface. Some warpage during the firing process is almost impossible to stop, I reguard this a feature of a hand made item over store bought junk. Apply glaze after bisque and fire or apply to bone dry and raw fire, what ever process turns out to suit.

Sam