Due to the binding structure of PMC, the firing temperatures are
fairly constrained. At most there is a nine degree plus/minus
temperature variation for the regular PMC. I’m not certain about PMC
plus, because the firing time is so much shorter. Regular PMC
requires two full hours for firing.
Chris Darway in New Jersey and Metalwerx in Boston, will fire your
PMC for just $1 a piece including tumbling. If you need more
email me off line.