Sunday, October 15, 2006

Final Firing of Patricia?

The kiln has now been fired fifteen times. Her name is Patricia, because she is level-ish and the bricks were stacked straight-ish. We fired her for possibly the last time yesterday, Saturday, October 14th. It was fired by Tony (who has fired the kiln with me many times), Brandon (who signed up for the firing as a class through the Edina Art Center), my wife Rachael, and myself.

Fifteen firings is a pretty short life span. A kiln of that size and design would typically be expected to last at least 100 firings. It is designed to fire glazed pots rapidly. Unlike many contemporary wood kilns, it is not meant to deposit a lot of ash on the pots. It is, rather, a design an individual potter might use to fire glaze-ware when they would prefer to use wood as fuel instead of oil, gas, or electricity. The kiln is relatively small, and a potter using it as their primary kiln would likely fire it once a month or so.

If this really proves to be the final firing, why the early retirement? Simply put, it was the first kiln built by everyone involved in its construction and we didn't know what we were doing. It was built by my high school students, and as we have fired it we have learned many things we should have done differently. It is an Olson fast fire design. In theory it should be able to fire in six hours. Our average firing time has been about 18 hours and is getting longer. Why it is getting longer of late I really don't know, but my guess is that the gaps in the bricks are getting wider as the metal frame around it continues to expand and the arch continues to droop. But as for the extremely long firing times, the primary problem is that the kiln was built with hard brick instead of soft brick. Soft brick is an excellent insulator. Firing a kiln built of soft brick involves heating the pots in the kiln, the shelves, the air around them, but not the kiln itself. Hard brick is not an insulator. It absorbs heat and gives it off. When firing a hard brick kiln, you need to heat the kiln itself to temperature and that takes a lot of caloric energy.

Brandon started this last firing at 5:00 am. Tony came in at 10:00 am and worked with Brandon until 11:00. At that point Brandon went home and Tony worked alone until I arrived at 2:30. I made several runs for pallets during the day, and then we worked steadily for several hours to cut them all up before we ran out of daylight. It has typically been taking us fifty pallets to reach temperature. Rachael came to help at about 7:30 and Tony went home to prepare for a raku firing he was doing the next day at the Eagan Art Center. Rachael and I finished busting up the wood and then settled in for our work. I was expecting we would reach temp by 1:00 am. We called it a night at 3:00 am, and cone 8 was only halfway down on the bottom. That was 20 hours, and in my book it just isn't worth it for the number of pots that fit in it. I think we could easily build a kiln that can hold four or five times the number of pots and fires in 30 hours.

So If any of the students who built that kiln ever read this, I thank you for your work. I have to laugh at how many nights we struggled into the wee hours of the morning trying to get that thing up to temp. Your parents must have thought your ceramics teacher was some sort of cruel and insane pyromaniac. I am amazed that none of them ever protested, or called me with concerned questions about what I was doing with their children until three in the morning. In the end I have learned a great deal from this experience. I hope to build more kilns in the future and maybe we will get a chance to fire together again.

Saturday, October 07, 2006

mural for the new room

This year, we in the art department at Edina High School, got to move into our new (not quite finished) rooms. The ceramics room is a bit smaller than the old one, but much nicer. The ceilings are very tall and very blank. We decided that we would try to fill them with art of our own making. Each student submitted a design proposal. We went through a series of discussions, edits, and several rounds of voting before the final design was chosen. As of this posting, the tiles are in the bisque fire. I will post another when the finished work is up. Clicking on "mural for the new room" will take you to some images of the work in progress.

Thursday, June 22, 2006

new backdrop

I got a new backdrop for shooting pottery, here is a sample. I need to build a light box diffuser. This was taken with just light from the windows in my living room on a canon 20d

Wednesday, June 21, 2006

adam and the lee family curse

Adam and I recorded around 15 songs in the spring of 2005. It was just before he got married, right after he moved here. We went to the terrarium and mostly got drum tacks layed down. A year has gone by and we have something like four songs finished. The work of adding guitars, vocals, and other embellishments falls largely on Adam. I put some of the drum arrangements together using Logic, and sing the occasional back up vocal, but he does the rest. He is very busy doing his residency and doesn't have the luxury of summer vacation like us teachers do. Here are a couple pics of the studio in his new house.


I was given the opportunity to participate in art a whirl this year. The mother of one of my students has a studio in the California Building. She told me she didn't have any work to show this year and offered the space to me to sell some things. I said yes, made a ton of pots in about two weeks, invited my friend Martin to participate, and then fired the wood kiln with just our stuff. It was about 2/3 mine, the rest were Martin's. In general the firing was disappointing, the pots were dark and brown, and the kiln didn't get as hot as we wanted. It was hard to fire it with just two people. We had some help though. A few students past and present stopped by to help for a little while, Rachael also helped out quite a bit. Here are a few pics.

Kyle and Martin loading

Derek stoking

here is my beautiful wife in rain gear (she's the one on the right)

pots before and after the brownification process (pardon the sarcasm)

the setup at art-a-whirl before we put flowers in the vases and made it look pretty. we had a poster size print of the kilin being fired at night with flame coming out of the stack, it was pretty sweet.

Sunday, May 14, 2006

kiln wear and tear

Here are some details of the kiln. The stack fell off before the last firing in february '06. I put it back up with some angle iron bracing. The kiln's frame was inside the insulation for the first four or five firings before we started noticing that it was super heating and bending. The bending frame allowed the arch to drop a bit. As the arch sags the walls get further apart. As a result, we have a gap in the door as we brick it up. We have since moved the insulation away from the frame. It is interesting to note that in the arch of the kiln there are a few bricks which do not seem to be reacting to the atmosphere in the kiln. They appear to have remained unglazed.

back pressure

After reaching temperature, we stuff both fireboxes completely full of wood, seal them as best as possible and then close the damper.

Thursday, April 13, 2006

Habitat for Humanity Spring Break Trip 2006

Rachael and I took 11 high school kids to Olympia Washington to voluteer for Habitat for Humanity. They are building 15 houses on the sight, in a cottage style development with a shared common space. All the houses are built green using a concrete wall system poured into foam forms that become the insulation. The foam pieces fit together like leggos.

  • Pictures
  • from our trip.

  • Website
  • for the South Puget Sound Habitat for Humanity Chapter.

    Thursday, March 30, 2006

    2 squared mugs

    I made a batch of these squared mugs to sell at the Mississippi Market. I gave a few to the custodians at school. It is important to keep them happy. They don't like dealing with the clay. These were fired in the electric kiln at school (oxidation). We use premixed glazes from Continental Clay.

    Sunday, March 26, 2006

    More pots

    These two vases below are the same as the two on the right and left above. They were fired on their sides. The picture above shows the side of the pots that were exposed to the ashes in the kiln, the pics below show the sides that were facing down. The marks you see are from the wadding that keeps the pieces from being fused to the kiln shelves. All three are about 14" in height

    this one is about 16"

    pots from the wood kiln

    Vase with squared base. I learned that from a Bob Briscoe workshop. That is mostly unglazed, there is a band of mamo on the top. we usually add a couple pounds of soda and salt.

    some lidded jars, these also have a mamo glaze, but only on the one side, all the drips on the other side are from the ash. They are 14" in height

    building the EAC wood kiln

    The kiln is of the Olson fast-fire design. We left out the little hole for poking out a brick designed to reduce the size of the flue to the chimney. We miscalculated the number of bricks and ended up with a chimney that was way too short. the first time we tried to fire it we made it to cone 04 after 20 hours or so and gave up. We then added a three foot stove pipe to the top and got to cone 10 (barely) in about 20 hours. The kiln stayed like that for five or six firings, struggling to get to temp and then eventually another 3 foot section of stove pipe was added. Now we can get cone eleven flat on the bottom (if we want to) in about 18 hours.

    wood kiln in use

    Here is a picture of the wood kiln my students built as it nears temperature. Tony and Jake are stoking simultaniously. The kiln was built by 6of my students at Edina High school in the spring of 2004. We sold pots at a local grocery store to raise the money for materials. The store gave us a huge display area right near the cash registers and didn't make up the prices a penny. As of March 2006 it has been fired 12 times, and is starting to fall apart. The kids named her PatrISHa, with particular emphasis on the "ish". I think they were refering to the frequent usage of the suffix. An example, "Does that look straight to you? I'd say it is straitish."