Chronicles of a Wood-fired Kiln


We had a half-finished kiln sitting out behind the studio, a project from a former professor and although I knew how to build a kiln, I couldn’t get excited about finishing someone else’s project.  Mark assured me that the college would plumb the gas lines for it, but that would be weeks, no, months before that happened. What I really wanted to was to learn how to build a simple wood-firing kiln, something I could set up anywhere.

My former student, Sara became the catalyst for my ideas.

Sara enclosing the sculpture

“Let’s just do it!”  she said.   I finished my sculpture and researched simple, fast firing kilns and decided a bottle form would do it.  So we built up a firebox on the existing kiln floor, set the sculpture in, and stacked kiln bricks around her, gradually angling in until a kiln shelf reached across, and then a layer of kao-wool on top.

 

Deb lights the fire

 

 

 

 

 

 

 

 

 

 

November 2

 

 

9:10 am – First fire – we lit the first twigs and newspapers in the firebox. Smoky at first and  the first worry of the day commenced: Will it draw? I circled the kiln until the smoke puffed out of the crevices in the top, where the kaowool didn’t completely meet the sides of the kiln wall. Resolved.
Little fire, we are concentrating on keeping it small until noon; it is a sculpture after all and this is a bisque firing. A fast one, I hope. I used a raku clay body, plenty of openness and resistance to thermal shock.

Deb and Richie are all about the fire, I haven’t had to touch it yet – they are taking turns feeding it. 

Squirrel cage fan is in position – maybe a little too close ?  I’ll see how the heat goes, but the design I looked at had the fan very close to the coal bed.

 

 

Pyrometer does not seem to be working.

10:47  Pyrometer IS working, shows 350 degrees F, climbing to 400. Easy, easy does it, don’t stoke that fire too much.

My 4 lb. log splitter is AMAZING.  With good aim I can split a chunk of wood with one blow. Sweet feeling, I can’t explain it.  We have been taking turns with it. Richie  is drawing on the kiln with a smoky stick.

Did I mention the pyrometer is working?!

 

 

I heard 2 or 3 muffled pops, so I climbed to the top and lifted the kaowool.  Still dark in there, everything seemed to be intact. Won’t know until this is all over with.  She could be seriously cracked and damaged, and this would be like carrying a stillborn baby to term.  I console myself, saying even if she doesn’t survive, the experience of firing this kiln is still a success.

I begin to forget she’s even in there.  Every minute is all about the fire.

11:16  Temperature stable at 400 degrees.  I started the fan on low, adding more wood.

11:47  550 degrees.  We put hot dogs on the grill and burnt them quite nicely.  

I’m splitting the quarters into smaller pieces to make it easier to feed the fire. I’m needing to stoke about every 5-7 minutes with the fan on its lowest setting.

Deb predicts 10 hours, which sounds about right if all goes well.

12:15– 600 degrees, barely.  Maybe closer to 575, this old meter is not as precise as a digital. Opened up the fan a little more.  Really, really hoping to do 200 degrees per hour. Sara’s here! Brought carrot raising salad and put more dogs on the grill.  They are….delicious.

12:50 – The first doubter makes an appearance.

“How high are you going to get it?”  he asked.

“1900 degrees”, I answered.

He laughed, that kind of laugh that believes what you just said is ridiculous. I looked at the pyrometer, and the temperature was down 50 degrees.

I upped the wood and turned up the air (the fan is audible now), and cranked the heat back up to 650, but I’m nervous. Lunch is over, well-wishers are dispersing, and i am chinking cracks and building up bricks wherever I feel a bit of heat leaking out. Did I say nervous?  I’m afraid.  Afraid that I will be here at dark and out of wood and have to walk away defeated.  Failure is a real possibility.

1:11 – added a kiln shelf door in front of the firebox.  Still sitting just above 600 degrees.

1:35 – I looked at my kiln design notes, and realized my fire was much too close to the opening. Pushed it all back further.  Gained 50 degrees right away!  My mom called while I was inside.

1:42 – 700 degrees! Called mom back. Yeah, Mindy is fine, her power came back on day before yesterday.

Sara’s friend came to keep her company. I am no company at all, pacing around, checking the fire, fretting over the slow climb. More wood.  Little more air.

2:25 – Fan is up all the way. 750 degrees.

Fiddling with the openings in the top, defining the apertures better to see what helps. Pushed the fire way in. Surely now the temperature will rise.

2:36 – 800!

2:52 – 900 after really packing it full of wood.

3:20 – 950; lost 100, then stoked it furiously and got it back. I’m tired but not out of energy. Kenny called to check on me.

I see flames up in the main part of the kiln and I know that is what I need to maintain  increase, until fire is coming out of the top.

Sara and Olivia said goodbye.  Only Richie is left, asking now and then if he can help.  I need to keep it stoked, keep it stoked, keep it stoked.   

3:25  1050!  Hallelujah! Only another 200 to reach quartz inversion.

Facebook sucks.  I posted about the kiln and nobody sees or nobody cares, everyone is checking in at restaurants or re-posting dumb pictures, like any of that matters when I am trying the greatest experiment of my ceramics career.

3:35  1100 degrees. Breathing easier now.  I didn’t know that I wasn’t breathing deeply until now – too anxious.

Cone 022 is down!  I love you, pale fragile little melting cone, I love you.

More wood. I know I need to go easy the next hundred degrees, but I can’t lose any heat, I just can’t.  Am thinking seriously about what temperature I will be satisfied to achieve. 1800? 1600?  Probably.  If I lean my head back and close my eyes it feels so good, so good.

3:48 – almost 1150. Perfect.   

4:01 – 1200 degrees.  I’m splitting more wood to celebrate.

The fire seems to need a combination of split wood and and smaller twigs and branches. Richie splits more when I stop to stoke the fire or write.

 

 

Amber texted, “Where is the fire? I’m headed out in 30 minutes”.

You’ll see it, just head on out here.

If I had a cigar, I would smoke it.  Not yet?  Maybe its a little early, but surely more than one father broke out a cigar while the wife was still in labor.  You gotta do something while you wait.

Only, I can’t do anything. I can’t even make myself go inside for a while. I can’t bear to leave the fire, I’m so afraid I will lose temp again.

4:38 – Which I did anyway, talking to Mark instead of tending the fire which requires near constant feeding.  But. 1300.

I would really like it if Kenny came out to be with me for a little while tonight.

5:00 –  Amber drove up with a minivan full of pallet wood, bless her wonderful sweet soul.  We quickly unloaded and as soon as I put a couple of those slats in, BOOM!  1550 degrees!

Amber keeping me company

5:18  1700, cone 010 bending  

5:30 – 010 down, 08 down!

5:45 – 06 down

 

 

 

 

Richie and Amber talked video games, and then he took his leave.

 

 

 

6:30 – Kenny came out to bring me a cold bottle of water which I happily guzzled.  The security guard, Gene, checked in. “I never thought I would see this thing get fired”, he told me.

Me either, me either.

6:55 – cone 04 down.  DONE!  

Now what?  Amber wanted to know.  Turn off the fan, put the kiln shelf over the firebox opening. Let it all die down. Go home to eat and take a shower.

We tried to take pictures of the glowing figure inside, but the camera’s couldn’t take the heat.  I could see the baby’s hand resting on the mother’s breast, glowing orange.  I picked up my axe and put my stuff in the car.

 

 

 

 

 

 

 

 

 

 

November 3 –  Utterly exhausted, even after a long night’s sleep.  Headache, back hurting, but feeling so good about what we accomplished.  Can’t wait for it to cool down enough to see what happened in the fire.

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About genieearle

I make things in my tiny studio called Claywise, as I try to understand the world I live in, and what it means to be human. I have 4 amazing offspring who are making their own paths, and I am currently an outpatient counselor at a drug and alcohol rehab center, where we do expressive arts in group therapy. View all posts by genieearle

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