What causes "s" cracks on the bottom of my hand thrown pottery?

Question: What causes "s" cracks on the bottom of my hand thrown pottery!?

I checked the bottoms and they are only 1/4 inch thick!.Www@QuestionHome@Com

Best Answer - Chosen by Asker:

Potters say that it is due to "lack of compression" - i!.e!. act of hand or finger pressure on the clay, resulting in lower moisture content and a denser structure!. Lack of compression in bottoms of pots can result in “S”-cracks!.
the problem is discussed at http://www!.potters!.org/subject10935!.htmWww@QuestionHome@Com

Many times "S'" cracks are caused by drying your piece too fast, try slowing the drying process, wrap it, or even if you feel you have time sprinkle some water on the clay before you wrap it up!.Www@QuestionHome@Com

If you stopped throwing your pottery around, it probably wouldn't get cracked!. Maybe it's not an answer, but it's helpful advice!.Www@QuestionHome@Com