A group from the Hawaii Potters Guild had a pit firing and raku firing on Sunday, April 21 deep in the woods of Kaneohe. It was the first time I'd pit fired, so I was excited to try the process. Before Sunday, I'd thrown two pots, one in B-Mix with grog and the other with a recycled white clay that was made up of porcelain and stoneware. When the clay was hard leatherhard, I put on terra sig which had been provided by Steve Martin, my ceramics instructor this session. I applied the terra sig with a Purdy paint brush, but in the end it seemed a bit streaky. Maybe I should have put on more layers. If I remember correctly, I put on 5 layers. Was nervous to add more just in case the terra sig became too thick and peeled off. Burnished the pot with my burnishing rock when the terra sig dried. Found out that Steve has a special rock he's used for burnishing for many years and has given it a name: Betty. No one is allowed to use Betty except for him. It's perfect for burnishing, from what he told us, and he's afraid of losing it if he lets anyone else borrow it. When the pot was bone dry, I did an oil burnish by rubbing a little cooking oil on a few inches and then burnishing with a plastic bag. Steve did a low fire bisque of our pots at cone 018, about 1300 degrees F. The day of the pit firing, we used a steel drum that had been cut in half, and a commercial grade cooking tub that Steve had found at a school cafeteria that was being remodeled. Both were packed with fine sawdust at the bottom and we laid our pots down on it. Those with smaller, rounder pots either placed the top or bottom into the sawdust. The longer pots were laid on their sides. Wherever the pots were submerged in sawdust, there was heavy reduction because of a lack of oxygen and that part of the pot would get black from carbon. I also found out that sawdust that I had pushed up around the sides of one of the pots would fall away in the firing, the area would oxidize and leave a halo around the black. I'll have to do that again. We placed a cornucopia of stuff around the pots: driftwood, thin copper wire, copper sulfate, vermiculite, Miracle Gro, fine steel wool, dried seaweed, eye of newt... Each of these has different salts and minerals which volatilize at different temperatures and fume part of the pots. Again, the part of the pot that's in the sawdust gets black, even metallic black, but the rest of the pot can take on the different colors of the salts and minerals which are fuming it. On top of this stew we placed smaller and then a few larger pieces of kiawe wood. We didn't put a deep layer over the pots so we didn't have a problem with any of them breaking, and we didn't add additional wood during the firing. The whole process from beginning to end took about 5 hours. We took the pots out when they were still pretty hot and placed them in an area that was protected from the wind. Within 30 minutes they were cool enough to handle and clean. I've included photos below. Some of the potters were also doing raku firing, but I wasn't doing that so I didn't include photos of it. Mahalo to Bridget Hangsleben for the photos. Bridget is a professional photographer and if you'd like to contact her, email her at BTransition@hotmail.com. Hope you can join us next time we pit fire!
8/14/2013 02:06:05 pm
Awesome work, excellent social commentary, internal-monologue, and editorial-isms. You're like a mild-mannered Dennis Miller/Patrick Swayze rolled into one. I laughed like a mad man.
9/15/2014 11:46:17 pm
I changed my mind. I put floor wax on my pit fired bowl twice. Now I want to put on a mid fire clear glaze. Is this possible?
9/17/2014 04:21:19 am
Some of this is possible, but maybe not all of it. The part that's possible is getting the wax off and then putting on a clear glaze. That seems pretty straightforward. If you don't get the wax off, you can't apply a glaze, so you need to rebisque the pot to a temperature lower than mid fire. Because the pot has never been fired to cone 10, it should still be porous and will be simple to glaze. So the process is a fairly straightforward one: rebisque the pot to get rid of the wax and then put a clear glaze on it. But will you keep the colors and patterns you developed in the pit firing? Probably not. Even if those effects survive the bisque firing (and they may not), they will probably burn away before the mid fire glaze begins melting. But I'm not sure. In my experience, the best way to find out is to do something as well as you can and as thoughtfully as you can and then you'll know. If you want more advice so you can do this more thoughtfully, I'd certainly recommend going to www.ceramicartsdaily.org, click on "Forums" on the far right, and ask your question under "Clay and Glaze Technical." You should get several responses from potters much more knowledgeable than I am. Your question is a good one and I'd like to find out more about this as well. Hope this helps!
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