This fall was crazy busy but fantastic. In September I started working as a ceramics technician at Mt. Hood Community College. I’ve been involved with this program for years (started out as a student in 2005), and I am so excited to have this opportunity, which is a lot like that of a resident artist. I have a private studio space, which I share with the other technician, Brenda Scott, who happens to be a great friend. I have access to wood, soda and gas reduction kilns, not to mention the opportunity to mentor young potters and help shape programs and workshops.
Our big project for fall quarter was to demo and rebuild the catenary arch of our boury box style wood-fired kiln, Little Woody. LW is a well-loved kiln. It can be easily filled by a handful of students, and takes only about 16 hours to fire. It can be candled with either gas or wood, depending upon students’ energy and sense of adventure.
You can see the general design in this photo. You can also see the signs of wear in the outer layer, on the right in the photo. This kiln was built about 10 years ago, and has likely seen over 100 firings. Back in the day, students also introduced salt into the kiln, which eats away at brick pretty quickly. They stopped using salt by the time I came to MHCC in ’05, but since then I’ve seen the floor rebuilt, in addition to spot repairs in the interior arch, firebox and flue.
The door is from an incinerator, and was installed upside down. This caused a bit of a headache during firing, because the door needed to be propped shut.
The first step in the demolition was to tear off the insulating layer covering the hard brick catenary arch. Turned out, this layer was composed of about 3″ of clay, covered in kaowool, chicken wire and, finally on top, a thin layer of refractory cement.
As you can see, it was a solid sheet of clay. Get out the sledge! Giant chunks of clay, some weighing 50 pounds +, slid off the arch as we wailed away. A local brick company donated a pallet of hard brick, so we weren’t concerned about salvaging every brick in the old arch. We beat that thing to smithereens. 🙂 Demo is fun!
Below is Jeannette working on the other side of the arch, where is connects with the chimney. I could not see it with my naked eyes, but the camera picked up the debris in the air.
Obviously, LW needed a new arch. This one could have come crashing down on the next firing. After we removed all the clay, wool and wire, Jeannette tore out the back wall before tackling the arch itself.
Wait, just how stable is this baby? The integrity of the once gracefully strong catenary arch seemed compromised. Once we start pulling brick, how long before the whole thing comes tumbling down (quite a while, as it turned out)? The floor is in really good condition, so we had to protect it from falling hard brick. Luckily, this is a pottery studio, and potters are notorious pack rats.
We happened to have a bunch of bags of scrap foam cushioning lying around the kiln barn. With some plywood covering the floor, and an empty, upside-down trash can to fill some space, we stuffed the rest of the void with these bags of foam and got down to business.
Everything came apart quite easily. Jeannette had torn down about 80% of the arch before the remainder came crashing down. Looking back, I would have been a little more organized and methodical about the tear down. We received a pallet of hard-brick as a donation from a local company, so I thought we would only keep the really nice brick out of the old arch. While we didn’t throw anything away until after the new arch was in place, I wish we had organized the old brick in terms of length.
With the arch cleared away, we had to cut the kiln’s metal frame in order to remove the cast iron stoke door. Before putting the arch form in place we had to build up the first few rows on the chimney side and reset some sketchy looking bricks around the flue.
“Hey, did you guys notice how the chimney brick is kind of separating? And how about how the firebox seems to have twisted?” We could have easily torn the whole thing down if we really wanted to make things perfect. Although these quirks of the kiln did make reconstruction a little frustrating, they didn’t compromise the integrity of future firings, and trying to fix them would have compromised our sanity.
I’ll end this post here, as it seems to be getting long, and it did take me many many days to put this together (yes, I can procrastinate). Look out for chapter two: the rebuild.
2 thoughts on “What I’ve been up to”
Great story and the pictures very helpful as I am thinking of building a catenary kiln. Do you have a follow up article about the rebuild? Do you have any design plans for the kiln?
Thank you, Mijimberi
Hi Mijimberi, I don’t have a follow-up…wow, it’s been so long since we re-built that arch! And since then I’ve turned into a cone 6 electric-firing potter. From what I remember, the kiln was based on plans found in Jack Troy’s book on wood firing. The kiln was originally constructed long before I started taking classes there, and when we did the rebuild I basically just cataloged the layout of the old arch – brick by brick – to reconstruct it. If you haven’t seen Jack Troy’s book yet, I highly suggest checking it out! Best of luck!