Thanks for the info - will try my cone 6 clay and working thicker.
Bowls I have seen here have been thin walled but I can see that the thickness and lower temp will create less stress and more strength. Guess it's time to throw some more bowls rather than trim what I made today. Min - thanks for your picture. I have put in more carving - perhaps that adds to my problem too.
Ask questions - it is a good way to learn - and many have helpful answers here.