Sunday, April 18, 2010

Firing with friends

The firing ended well. Krista and I were starting to wear down a little early so we pushed the firing a little faster toward the end and closed up the kiln Saturday morning. Everything went well in the end with cone 10 down everywhere. Here's a picture of Krista toward the very end of the firing using our version of the "flamethrower" or "wooden lid" or "rifling" (or whatever else you might want to call it) technique--basically stuffing the door with small sticks with each stick resting on the one below it, but still allowing air to flow between them all. This is a good technique to increase temperature while controlling ember build-up.

Of course being a new kiln to Krista and me, we could only guess how much reduction we were getting. I feel fairly good about the amount of reduction in the front of the kiln. We were aiming for a fairly heavy reduction in comparison to what we aim for with our own kiln here at Windy Ridge. The reduction in the middle and the back of the kiln though, is a little more of a question mark.

Krista learned how to fire from the three years she apprenticed with Kevin Crowe. Kevin emphasized making the firing a community event, and Krista wanted preserve that idea in this firing at Bethel. We had a large potluck on Friday evening as we reached top temperature in the front of the kiln.

And friends stopped by through out the firing.

Overall it was a good experience. One lesson that was strongly reinforced during this firing is how untrustworthy pyrometers are. Cone 10 started moving when the pyrometer said 2160 and we started to side stoke the kiln aiming to hold 2160 in the front of the kiln. As we progressed, the temperature started to drop in the front of the kiln. Eventually we stopped side stoking when the temperature in the front dropped below 200o degrees. We struggled to get the temperature back up to 2100 for several hours. When we finally stopped and looked in the kiln, cone 11 was down and 12 was soft... Pyrometers seem like they should be such great devices, and they usually are, but it was good to be reminded not to rely on them too much.

Unloading next weekend. I'm looking forward to see how our pots look in this longer firing. I have to admit I've had a dream of building a small anagama kiln maybe a small candle shape kiln similar to something described in Furutani Michio definitive book "Anagama: Building Kilns and Firing". It's really just a dream though, I do love making our functional glazed pots, and I couldn't ask for a nicer kiln to fire them in than ours. However it might be fun to have a small anagama which we could fire once a year. A great project.... for 2025...


brandon phillips said...

i use a pyrometer strictly for watching temp gain/loss. it's off by about 50 degrees or more at cone 10 but i've never calibrated it so that i'm not dependant on the temperature reading.

Hitomi said...

We read Anagama book often and still we learn a lot. Our Anagama was inspired by the book, and hasn't fired yet but we will try to have it in this fall. We can't wait.

Mr. Furutani built more than 30 anagamas in his life, and I think you can build yours in the very near future, not 2025! Hitomi

Michael Mahan said...

Last firing, we decided to focus on cones. But we kept looking at the pyrometer, saying "I'm not really focusing on it, but the pyrometer is at..."

One thing I don't understand is my my cones 12 and 13 started tipping at the same time. We wanted a cooler temperature in front this time, but we ended up at cone 12/13 this time too.

When 9 dropped in the front, I pushed the active damper in about 2 or 3 inches and slowed the kiln way down, stoking for four more hours, and we got 9 just barely tipping in the back part of the kiln.

Thanks for sharing your experience.

ang said...

looks like a great community thing, we do that with the big kiln at the club it takes away from the pressures of long firing alone...hope its a good firing and look forward to some pics..

Joe and Christy said...

aiming to hold temperature at a certain cone is more difficult than one might think. Having two cones fall at the same time is quite common, especially if you are raising the temperature at a moderate rate. I don't know how long you hold the kiln at top temperature. The longer you hold the top temperature the cooler you have to hold the temperature. We hold our first chamber at top tempature for around 8 hours. As soon as we see cone 9 getting soft we stop raising the temperature. We usually end up with 11 down and 12 getting soft when we move on to the second chamber. Hope that helps.

Ron said...

Fun to see everyone there sharing in the firing experience. I've always been a proponent of longer firings, I always found I got better pots from my salt kiln if I stretched it out a bit. I'd love to have a small anagama. I think Norm Schulman has one in Penland and Ron Meyers too. I think both may be based on a small kiln that Chuck Hindes has or designed. Of course small to me may be very different than what small is to you guys. Ha. Have a great rest of the week.

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