Expert: Leisha Hiester - 3/5/2011

Question
If I am firing dinnerware.  What cone is safe for cooking/eating off of as well dishwasher safe

Answer
Jill,
What cone or temperature does your clay vitrify? Generally, there are 3 types of clay, Earthenware, mid-range and high fire. Earthenware fires at Cone 04-06. Mid-range at cone 5-7 and high fire up to cone 10.  
Your glaze needs to be lead-free or dinnerware safe. Most commercial glazes are now clearly marked. The glaze should fit the clay or fire to a temperature suitable to match your clay type.

Vitrification is the hardening, tightening and finally the partial fusion or glassification of the clay.

Find out what type of clay you have first. Never overfire your clay. If you overfire a low fire clay it will melt.

If properly vitrified and matched with a safe glaze, you should be able to use your dinnerware.

Hope this helps. Leisha