NotesThis happens on first fire for many bodies. Sulfur is an impurity in many ball clays and related stoneware and earthenware raw clays, it occurs as calcium sulfate (selenite, the same mineralogy as plaster). Different sources indicate wider and narrower ranges for this, it is difficult to establish exactly.
Out Bound Links
By Tony Hansen
•The secret to cool bodies and glazes is a lot of testing.
•The secret to know what to test is material and chemistry knowledge.
•The secret to learning from testing is documentation.
•The place to test, do the chemistry and document is an account at https://insight-live.com
•The place to get the knowledge is https://digitalfire.com