KNOWLEDGEBASE

KNOWLEDGEBASE

How to fire very precisely using witness cones

Automatic kilns and even manual kilns shut off by the use of cones are never as accurate as the human eye. 99.999% of the time this is fine. However, for the rare artist who needs the utmost precision, here is another method.

  1. Set your kiln control to fire about 25 to 50 degrees higher than you need to to achieve proper maturation of your witness cones.
  2. Know when your kiln will reach the approximate temperature that you want to achieve. Set the Alarm to start buzzing at a lower temperature (like 50 to 100 degrees below where the cones will mature. The Alarm is not very loud so be aware of that.
  3. Watch the witness cone through the peephole (or better yet several witness cones through several peepholes).
  4. Shut off the kiln power with the toggle switch as soon as the witness cone bends to the proper degree.

Note: This is essentially what potters did before they had automatic controls.