Cone Blue Pottery shows how to design and construct a small propane fired kiln for firing pottery in oxidation and reduction environments. Ceramic glaze research and development are the mainstay of Cone Blue Pottery. More details can be found on the website ConeBluePottery.com.
Potters often have trouble cutting gas ports of precise size into the sides of a kiln during a kiln conversion; the proper type of hole saw and how to use it is covered in this video. Difficulty in firing converted kilns is often the result of potter’s choosing the wrong size or type of burner. The Ward B2ventury burner outfitted for propane (www.wardburner.com) was used in this project because it’s well matched for the BTU requirements of the kiln used. A side by side demonstration of the B2 vs a common cast Raku burner is included, showing the superior control of the B2 burner. The econox (www.econox.com) oxygen sensor 012179 carboprobe HT was used due to its higher resolution, which is important when doing research and development of ceramic glazes. A modular chimney design was utilized in this project (to allow the kiln to be taken apart and stored inside). A step by step construction of both the chimney modules and the kiln construction are shown. The dimensions for the port opening, flue size and chimney height were made using guidance found in Frederick L. Olsen’s book “The Kiln Book” ISBN 0-8019-7071-7.
Ceramic glaze test results are shown for iron oxide (Fe2O3) and copper oxide (CuO) containing glazes. There is evidence of reduction and reprecipitation in the iron oxide glaze and of multiple reduction levels in the copper oxide glaze. The presence of the bright red color in the copper oxide glaze is evidence of reduction to base metal. The kiln fired to cone 8 in 5 hours. I will aim for cone 10 in the next firing by adding insulation. A future video will show those results.
“Converting a Kiln from Electric to Gas (2019)” is a closed caption video produced using Cyberlink Power Director software.