Even if you have never fired ceramics before, you should get good results by following these 10 guidelines and reading your kiln instruction manual.
1) Dry the greenware thoroughly before firing. Place the ware against the inside of your wrist. The ware should feel warm. Drying the greenware before firing will eliminate explosions caused by moisture in the clay turning to steam.
2) Know the cone number for each clay and glaze, and fire to the correct cone. Correctly label clays in storage.
3) Do not mix clays rated to different cone numbers. Firing ware of different clays in the same load can result in melted clay running on the shelves. (Example: Do not fire stoneware and low fire ware together.)
4) Place pyrometric self-supporting witness cones on the shelf. The cones are inexpensive, take only a moment to use, and verify that the clay and glazes received the correct amount of heat work.
5) Keep shelves and ware at least 1” away from the thermocouple or Kiln Sitter tube. Ware or shelves placed too close to the thermocouple can cause inaccurate readings. Items placed too close to the Kiln Sitter can cause an overfire by preventing the rod from dropping.
6) Vent the firing chamber during the initial stage of firing. Either prop the lid or use a down-draft kiln vent.
7) Fire slowly enough to burn out impurities from the clay. Most firing problems are caused by either a poor fit between clay and glaze or firing too fast.
8) Monitor the kiln during firing. Occasionally check the kiln, especially near the end of the firing.
9) Become familiar with the color around the lid and with the noises that a kiln makes during firing. You can tell approximately what temperature the kiln has reached by the color of light around the lid. A kiln’s noises, like engine noises, can warn when something is wrong.
10) Keep firing records. Write down what you learn from each firing.
Wishing you a great fall season,
Arnold Howard Paragon Industries, L.P. - Better Designed Kilns 2011 South Town East Blvd. Mesquite, TX 75149-1122 Voice: 972-288-7557 & 800-876-4328 / Fax: 972-222-0646 firstname.lastname@example.org / www.paragonweb.com