January marks the end of the second year that I've been working with clay. The highlight of this month has been learning how to fire the gas kiln at HPG. For more than a year I've been loading and firing the electric bisque kilns, but I'd never had a chance to learn how to fire the gas kiln. I'd asked Kenny Kicklighter, the head of the kiln team, if I could learn how to fire it and become part of the firing rotation, but he wanted to wait until he thought I was ready. Well, in December Kenny approached me and asked if I was ready to learn. Kenny is not only an accomplished potter, he also knows more about firing a kiln than anyone I know. For many years he's been studying how to fire the kilns at HPG. For instance, there are currently 7 people in the firing rotation, including Kenny. Each time they fire the gas kiln they put 18 cone packs in different parts of the kiln. When the firing is over, the cone packs are placed on a board that lists their position such as top front right and so forth. He takes pictures of each board and when looked at in sequence these pictures have given him a general pattern for how our kiln fires. I was asked to study these and to read Nils Lou's book The Art of Firing. I guess that Nils had actually come to HPG about 8 years ago as a consultant when HPG was having problems with their gas kiln. He not only made adjustments to the kiln that got it working better, he also gave personal instruction to Kenny and other members of the firing team on how to fire this particular kiln. The firing protocol that Kenny uses is right out of chapter four of Nils' book. I also read parts of Fred Olsen's The Kiln Book and found that to be quite helpful. As usual I visited youtube to see if there was any instruction on how to fire a gas kiln. I found a few videos, but the information isn't clearly presented and the video quality is poor.
We loaded the kiln on Saturday, January 4. My first impression is that loading the kiln is the most important thing about firing a kiln. There were three of us helping Kenny, and we spent more than four hours loading. Quite a bit of attention was given to making sure that pots with certain glazes were put in particular parts of the kiln. We have a downdraft kiln that fires hotter on the bottom (cone 11) than the top (cone 9) and fires hotter on the right side than the left side. If pots are placed in the wrong areas, their glazes will either not mature or they will run off the pot. So the first thing we did was to go through the pots on the shelves and organize them according to their glazes, especially looking for glazes like Amber Celadon and UH Blue that need to be placed in very specific parts of the kiln. In the case of these two glazes, they needed to go in the back near the top of the kiln where it was coolest. Some pieces with underglazes and no other glaze on top needed to go on the middle top shelf in the back where both the heat was relatively low and the reduction was low. Kenny also warned us that if part of a bowl is sticking out from a shelf in the path of the flame, it will become hotter than the rest of the bowl and will distort (I've had it happen to mine). We use Rod's Bod to make our cone packs, and the Rod's Bod shows that certain parts of the kiln reduce more heavily than others. Kenny also makes small bowls from Rod's Bod, an iron-rich clay, that he glazes on top with a clear celadon (no added iron) and places in different parts of the kiln. He breaks these open after the firing to check for black coring. While we want a good body reduction, we don't want to overdo it and jeopardize the structural integrity of our pieces. The configuration of the stacks was also taken into account as well as the distance between each stack. We left at least an inch of space below each shelf so the heat could pass through more easily. All of this was a revelation to me. When the kiln was fully loaded, the door closed, and the oxy probe in place, Kenny showed me how to light the burners. It was 6 pm.
We met the next morning of the 5th at 4:45 am. When we checked the oxy probe we found the temperature at about 1600 F. Throughout the day we followed Nils Lou's firing protocol and recorded our readings on a chart. Kenny showed me how to use the probe, how to use dampers, adjust the gas, read the cones, interpret the flames, observe the ware, start body reduction, shift to neutral firing, start glaze reduction, etc. I was taking notes and learning quite a bit. When cone 10 at the top was at 9 o'clock (and cone 11 was at 9 o'clock on the bottom), we shut off the gas and closed everything up so it would cool down as slowly as possible. It was almost 6 pm.
We opened the kiln on Thursday the 9th at 5 pm. As usual there was a crowd of potters helping unload, clean kiln shelves, put on more kiln wash, and hoping their pieces turned out well. I certainly looked at everything coming out of the kiln with different eyes than I had before. After the kiln was unloaded, Kenny said the one thing he would do differently next time would be to start the glaze reduction a little earlier at a slightly lower temperature. We had quite a few pieces with celadons and they didn't get as much color as Kenny wanted.
I'm glad I'm learning to fire a gas kiln and that Kenny is mentoring me. I'll be helping Kenny on each of his firings until he thinks I'm ready to do it on my own. He also encouraged me to help other firers so I can see how they do it which will help me progress more quickly. It's funny how much this has changed my perspective on the process of making pots. Before it was so easy to just glaze a pot, lay it on a shelf and show up for the kiln opening. It was like opening presents at Christmas! Now I have a much better idea of how much work is involved in the entire process of making pots and how much skill is required to fire a kiln well.
We loaded the kiln on Saturday, January 4. My first impression is that loading the kiln is the most important thing about firing a kiln. There were three of us helping Kenny, and we spent more than four hours loading. Quite a bit of attention was given to making sure that pots with certain glazes were put in particular parts of the kiln. We have a downdraft kiln that fires hotter on the bottom (cone 11) than the top (cone 9) and fires hotter on the right side than the left side. If pots are placed in the wrong areas, their glazes will either not mature or they will run off the pot. So the first thing we did was to go through the pots on the shelves and organize them according to their glazes, especially looking for glazes like Amber Celadon and UH Blue that need to be placed in very specific parts of the kiln. In the case of these two glazes, they needed to go in the back near the top of the kiln where it was coolest. Some pieces with underglazes and no other glaze on top needed to go on the middle top shelf in the back where both the heat was relatively low and the reduction was low. Kenny also warned us that if part of a bowl is sticking out from a shelf in the path of the flame, it will become hotter than the rest of the bowl and will distort (I've had it happen to mine). We use Rod's Bod to make our cone packs, and the Rod's Bod shows that certain parts of the kiln reduce more heavily than others. Kenny also makes small bowls from Rod's Bod, an iron-rich clay, that he glazes on top with a clear celadon (no added iron) and places in different parts of the kiln. He breaks these open after the firing to check for black coring. While we want a good body reduction, we don't want to overdo it and jeopardize the structural integrity of our pieces. The configuration of the stacks was also taken into account as well as the distance between each stack. We left at least an inch of space below each shelf so the heat could pass through more easily. All of this was a revelation to me. When the kiln was fully loaded, the door closed, and the oxy probe in place, Kenny showed me how to light the burners. It was 6 pm.
We met the next morning of the 5th at 4:45 am. When we checked the oxy probe we found the temperature at about 1600 F. Throughout the day we followed Nils Lou's firing protocol and recorded our readings on a chart. Kenny showed me how to use the probe, how to use dampers, adjust the gas, read the cones, interpret the flames, observe the ware, start body reduction, shift to neutral firing, start glaze reduction, etc. I was taking notes and learning quite a bit. When cone 10 at the top was at 9 o'clock (and cone 11 was at 9 o'clock on the bottom), we shut off the gas and closed everything up so it would cool down as slowly as possible. It was almost 6 pm.
We opened the kiln on Thursday the 9th at 5 pm. As usual there was a crowd of potters helping unload, clean kiln shelves, put on more kiln wash, and hoping their pieces turned out well. I certainly looked at everything coming out of the kiln with different eyes than I had before. After the kiln was unloaded, Kenny said the one thing he would do differently next time would be to start the glaze reduction a little earlier at a slightly lower temperature. We had quite a few pieces with celadons and they didn't get as much color as Kenny wanted.
I'm glad I'm learning to fire a gas kiln and that Kenny is mentoring me. I'll be helping Kenny on each of his firings until he thinks I'm ready to do it on my own. He also encouraged me to help other firers so I can see how they do it which will help me progress more quickly. It's funny how much this has changed my perspective on the process of making pots. Before it was so easy to just glaze a pot, lay it on a shelf and show up for the kiln opening. It was like opening presents at Christmas! Now I have a much better idea of how much work is involved in the entire process of making pots and how much skill is required to fire a kiln well.
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