Firing Log

I video taped a little during the sixth firing, imported the tape into my laptop, and then let it languish for the last five months. I’ve been wanting to recover the 15gb of hard drive space it took up, and I was finally bored enough to stay up all night, cut it into little bits, and paste together a four minute clip.

You’ll see the anagama being fed, make a tiny steam tornado, and breathe fire. When the fire is pouring out the chimney, it’s like a river of bright water rushing over rapids. I could watch that almost endlessly.

One part may need a little explaining: about midway through the video, and at about the hottest temperature during the firing, I take out a “pull”. A “pull” is a piece specifically made to be pulled from the kiln so that the amount of glaze build-up can be evaluated. Pulls are crucial because the end of the anagama firing is determined by how well the pieces have developed ash glaze. Temperature is obviously a factor, but cones typically flatten out by the end of the first day of the three to four day wood firing period — where cones really fall down, is that they say nothing about the level of glaze build-up. By loading a few pulls, the glaze level can be checked quite thoroughly.

Without further ado, here are links to the video. Note: quicktime format; both are the same content but the 20mb clip is better quality, though a somewhat hefty download. I’d suggest doing a “save as” on the link as it might take five minutes or so even with a broadband connection.

~6mb video clip, really low quality

~20mb video clip, acceptable quality

I managed to get through Monday without any peeking. Really, the kiln is much too hot but the temptation is strong. To take my mind off things, I decided to build a paper kiln. I’ve been reading about these since college (15 years now) and I’ve always wanted to try one. Sunday night when I got home, there was a Sunday paper on my doorstep. It was a sign. I don’t subscribe.

Now, I also had a hole from getting dirt for the top of the kiln. Given a hole, a free paper, and a spike-pod piece that had been sitting around for a couple years because the tip of the spike got broken somehow, I decided Monday was the perfect day and this was the perfect project. It would give me something to open today and thus help me get through two days of the cool down period (ideally, at least ten days).

Let’s start with the hole:

I threw in some damp wood. This turned out to be a mistake because I couldn’t get it to light. What I needed was some thin kindling underneath the bricks that make up the floor — there is an air inlet underneath the top layer. I should have filled that with easily burned wood. As it is, I had to resort to the raku burner to get the thing going.

Then I filled it in with some millends. The millends are fairly damp too — they aren’t kiln dried, but being cedar, once they get going they burn like the devil:

Then I piled up more wood over top. They say that early kilns were simple pits with shards placed over top to help hold in heat. I don’t have any appropriate shards (I have lots of shards, but when I smash up stuff, I smash it into little bits), but I hoped the paper/slip wrap would function similarly. As it turns out, one Sunday paper isn’t quite enough to make a nice thick shell — it was only a double layer at the bottom and when things got going, it ripped:

Mixed up some slip (twice, needed 3x this amount):

Grabbed the paper:

And pasted it up, threw dirt on for good measure. Dirt is the cheapest most abundant refractory around. Great stuff:

I threw some hot coals down there and started waiting. Although it looks like they caught, when I’d pull them out the smoke would go away, so the smoke was from the wood I threw into the air inlet, not from the kiln wood:

To make a long and rain soaked story short, I eventually got it lit. But then it smoked like crazy — thick green smoke — the kind that looks like a liquid. The smoke was was bothering me a lot and although I knew speeding things along would damage the unbisqed pot, I was mostly interested in seeing some fire so I forged ahead anyway. I fanned the flames and indeed, heard some ominous pops from the kiln. At last it really took off and boy, what a sight:

Notice the cat in the middle to lower left. The kiln’s cats LOVE fire! Click the pic for large version:

Today, I retreived the pot. When I got to the pit kiln, I saw shimmering heat from the sides of the dirt walls. That surprised me … till I realized it was a shimmer shadow from the anagama chimney. I’ve never been much for pit fire and this piece hasn’t convinced me there’s anything there for me to do. Here’s the rather bland piece:

But then I turned it over. There’s glaze on the foot! Honest to goodness glass! I cursed a bit in a surprised and happy fashion. As arrogant as it sounds, I thought to myself, “if I can fire a hole in the ground to a glass finish, I can fire anything.”

Clicking on the following pictures opens a large view:

You can see the damage from pushing the fire, but so what? Glaze!

Here’s the worst hole:

The best was yet to come — something even more interesting than the pottery itself. When I dove into the pit to retreive my bricks before filling in the hole, I discovered the dirt had melted — really melted! I was simply amazed — it’s very brittle, but very cool. I’m thinking about incorporating dirt with firebox pieces in the anagama itself:

So there it is. I can melt dirt. What a great day and better yet, one more down in which I did nothing with the anagama. I have to work the next three days so that will help too.