I would like to start this post by saying that I am very thankful to the Northern Clay Center and the Jerome Foundation for giving me the opportunity to pursue this project. This past spring I was chosen to recieve a 2012 Jerome Ceramic Artists Project Grant awarded by the Northern Clay Center.
My project for this grant was to make a body of work using slips and glazes fired to cone 3 with terra cotta. I did not have much experience with low fire clays or glazes as I had worked primarily with porcelain bodies firing in reduction to cone 10.
I wanted to pursue firing to cone 3 as I could easily use an electric kiln and save a great amount of energy compared to firing at cone 10 with gas. I knew I wasn’t going to have easy access to a gas kiln and needed to be more independent if I wanted to continue making pots. I also wanted to be more environmentally conscious of the materials and energy I use. By using an earthenware body the clay becomes very vitreous firing to cone 3 and hotter, which I believe is stronger than stoneware or porcelain at cone 10. When I flick one of these cone 3 pots with my fingernail it has a sweet sounding glassy ring to it.
I started by doing some melt tests of frits, Gillespie B, and neph sye while firing the clay to temperatures ranging from cone 1 to cone 5. I tested different slip and glaze recipes from fellow potters as well as mixing blends during these first firings. I found a lot of issues with these firings, a minimal amount crawling and/or crazing, but many over fired or under fired glazes. The amount and type of frit in these glazes made a substantial difference in the outcome. I decided to use frit 3195 for glaze development as it has the highest melting point compared to 3110, 3124, and 3134 frits.
|some of the better slip and glaze tests|
I was fortunate to find a couple of good clear bases that fired nicely at cone 3. The clay body I decided to use is low fire red from Continental Clay as I know many potters who have used it for years. It is a high iron earthenware body that can be fired to cone 4 easily. At cone 5 I noticed a substantial amount of bloating with this clay. I bisque fire to cone 07 as that seems to be sufficient to keep from excess off gassing during the glaze firing.
|Varying amounts of fluxes, silica and epk while looking for a decent matte base. Most were under fired with a couple potential places to go from. It is much more difficult than finding a matte glaze at cone 10.|
I hope that this has been a helpful post for some of you. I know I am not an organized writer or photographer, but hope to influence more clay artists to question their footprint. I thought I would always use porcelain but I have gone “dirty” and don’t see myself going back.
That is it for today’s post. I will be back soon to share more of the results I have uncovered over the past months. Thank you for your time.