Monday, November 26, 2012

Soda Fire!!!!

In the wake of the great sickness, I frantically glazed all of my plates, cups, and bowls.  Each item was then carefully wadded onto it's spot on the kiln shelf.

Each shelf carefully balanced on the one before. 

By the time we lined up the rows up bricks to close up the door and spackled shut all of the cracks our hands were freezing and it was close to one in the morning. Many hours later we noted with pride no flames escaping from the top of the arch.  Our firing was consistent and even.  

Firing Shedule

12:45 am
mudded door and started candling, with peeps and damper open

8:00 am 
closed peeps, shut damper half way and turned up gas a bump (1/8th of an inch or so) and adjusted the blowers
11:00 am
checked on kiln
11:35 am
turned up gas slightly and closed damper to 2"
1:00 pm
cone 012 down, strong reduction, turned up W burner slightly 
2:45 pm
turned up gas a bump, damper mostly open, cone 012 completely molten cone 4 glowing at the top
3:45 pm same
4:45 pm
second cone 4 down on top, soft on bottom
6:00 pm 
second cone 4 down on bottom 
7:00 pm same
8:00 pm 
opened damper almost all the way
9:00 pm
cone 5 starting to go 
11:00 pm 
cone 5 down on bottom, soft on top, closed damper 1/2"
1:35 am 
cone 5 down on top, cone 7 soft on bottom
3:00 am
cone 7 down and 8 soft on bottom
7 soft on top
4:00 am
cone 8 down on bottom and 9 soft
8 soft (45 degree angle) and 9 just starting to bend on the top
4:30 am
cone 9 down on bottom 
cone 9 down on top
SODA from 4:30 to 4:50 (4lbs of baking soda)
6:00 am 
no change on cones
opened damper all of the way and turned gas down just a touch
7:00 am
bottom cone  10 starting to bed on top and bottom 
8:00 am 
bottom cone 10 at 45 degrees
(top cone 10 not visible)
bottom cone 10 down (top cone 10 not visible)
bottom cone 10 down, 11 bending
shut off kiln. covered blowers with kaol-wool.

These records are primarily for my own reference (or anyone else who is going to fire the soda kiln at The Missoula Clay Studio).  The overall gist is - it takes a LONG time.  It took us just over 24 hours.  In the future I think I would time the whole thing a little better and go home and sleep a few hours.  

Adam and the kids came and brought me breakfast and we all went home.  I took a shower and started cooking in preparation for our great getaway.  A few hours later I crashed on the couch while nursing Sylvan.  While I was unresponsive to the activity in our house Adam loaded the car and as soon as I opened my eyes we left the bricked up cooling kiln, our house and all media behind and drove off into the mountains. 


  1. Can hardly wait for follow-upt to great tale of immersion in art and family.


  2. Those are beautiful. I can't wait to see the final product. I had no idea it took so long and such close monitoring. Actually, had no idea what a soda kiln was. How do you decide which kiln to use? Where are the cones?

    1. The cones sit right behind those two bricks sticking out of the door. You pull them out and look in. The hotter it gets the harder they are to see. I am definitely remembering my sunglasses next time. Right now this is the only cone 10 gas fire Kiln that is available. In the future I will probably fire the new reduction kiln. it just doesn't have any shelves at the moment.

  3. At the Santa Fe Community College I viewed the pottery students show last week. (Almost all of the students are middle-age or older and are long-experience potters.) I saw very little work that compared favorably to yours, Heidi. At least two of the potters had soda-fired work on display, and one was interesting. She was impressed that you have access to a soda kiln and said that you are very lucky! She said the soda kiln is seldom used here as it is very expensive to fire.


    1. Thank you. I feel fortunate to have been able to fire the kiln. It is on it's last legs and needs some serious repairs. Gas firing is about twice the cost of electric firing, but the results are so different that it is worth the investment. Hopefully we will have a large gas reduction kiln available soon. I can't wait to get to use it.