Field and Michael Kline’s Kiln Shed
I get a little feeling Wyeth’s “Kristina’s World” whenever I see his kiln shed.
Before they get lost in my noggin, I wanted to share a few new things I’ve learned in the past month.
I’ve always loved watching other artists and potters work. It doesn’t matter what part of the process you witness, there is always something to be gleamed, fermented and utilized. These processes are nothing more than one a long series of decisions. Even firing the kiln is a cycle of action, observation, decision, and action again.
Having had the chance to help Michael Kline stoke his kiln this past month, I got to ease drop on some of the decisions another potter has to make during the firing. Extra bonus - was seasoned potter Alex Matisse, who was there to help as well.
Decisions Decisions…
There’s a book I like to look at from time to time. It’s left over from my days as a graphic designer. It’ s Edward Tufte’s Visual Explanations. It’s “about pictures of verbs, the representation of mechanism and motion, process and dynamics, causes and effects, explanation and narrative.” I’ve always been fascinated with how data gets visualized, and the many ways we can depict it in order to understand it.When you fire a kiln, you are given data from the kiln - be it time, a cone bending, color of heat, pyrometer reading, flame character, smoke, smell (oh how I love the smell of reduction!). But how do we visualize this data?
My first firing logs from electric kilns looked like a captains log…
10:30 1020 degrees…
1:45 pm 1600 degrees
4:30 2000 Cone 5 bending.
It allowed me to come close duplicating a good firing, but really the firing process was one decision at the beginning, and then waiting. The log was good because it matched how you entered a new ramp into the computer. But as far as visualizing what was happening in the kiln, it didn’t give me much.
When I started with gas firing in the little soda kiln, I bought John Britt’s book “High Fire Glazes” and the firing “graphs” were excellent examples in visualizing data. The book is a treasure trove of glaze recipes, but to me, those graphs were worth just as much as the recipes.
So, for my first gas soda firing, I chose the firing schedule that was right for the glazes I was using, and I duplicated it in illustrator on a full sheet of paper. I then used it during the firing and plotted my temp and notes, right next to the “ideal” line. I was able to quickly, at a glance, visual what was happening in my kiln and compare it to what I wanted to have happen. I could see if I was stalling, firing too fast, getting close to needing to start redux. When I got close to temp, I could easily see if I was getting to temp at the ideal “ramp”. just by comparing the angle of the line.
The New Firing Log
Previous firings underneath
I’d print out a new one for every firing, and be able to compare firing to firing using these graphs.
For my next kiln, the current fast fire wood kiln, I figured I’d do the same. I also added a space for notes under each time bracket, where I could detail what I did… added soda, started second fire box, etc.
Detail from the last firing.
All well and good, but I was presented with a another aspect of firing I hadn’t experienced before. The larger size of the kiln meant heat could be drastically different in different parts of the kiln. And I would notice that my top and bottom were 2-3 cones apart! The top being hottest. The graph sort breaks down when you need to add a third dimension to the visualization. It plots time/temp, but now we need to add space to that. Here’s where Michael comes in.
When I showed up at Professor Kline’s scene, I noted as many details in my head as possible. When visiting another potter’s space, I feel like I have my Sherlock Holmes hat on. I look at things and try to make sense of them, ask questions, and gather as much clay geekery as I can handle. When I first got there, I glanced at his firing log, it was “Captain’s Log” style. Time and temp written, with some notes. I wasn’t able to glance at it and understand “where” in the firing he was, until I converted temp to cone and saw he was sitting just below bisque temps. It was clear, the temp was rising, and that’s all that matters at this point.
A few hours later, closer to cone 7/8 bending, he did something brilliant. He stopped writing down captain’s log style, and drew a simple large cross in his log book and wrote down a different cone status in each corner.
I thought about what this meant, and when I couldn’t figure it out I had to ask. The four sections represented the four quadrants in his kiln. Top Left, Top Right, Bottom Left, Bottom Right. He said he generally only looks at the top and bottom cones and figures the middle will sort itself out.
It was a simple and beautiful representation of three dimensions of what was happening in his kiln, and allowed him to visualize it quickly, and make decisions. (”Cone Status” represents both temp AND time, or heat work rather, but still, there’s not need to graph those as the cones status encompasses both… leaving only the spacial dimension to deal with). We started feeding small kindling bits into one end to boost the heat in the bottom right. We’d switch which side we were stoking, to help move heat around as well.
Of course there are other nuggets of wisdom I picked up that day, but for some reason this is what stuck in my head the most.
Looking back at this blog post, I see I have written over 1000 words on such a simple thing as a firing log. I suppose I am a geek for these type of things, but on the other hand….
So much is written on what different techniques are used to create this or that effect: slow cooling; reduction cooling; oxidation soak, body reduction, carbon trapping; etc… but so little is written on how we get our kilns to do the things we want. How we visualize what is happening in there, will help us learn how to get our kilns to do those things.
You can download my firing graph in a .pdf format. The firing ramp is based on Reduction 2 firing (R2) schedule from John Britt’s book. Good for carbon trapping, shinos, and iron blue celadons.
================================================
Even if you fire in an electric kiln, and even better if you only had a kiln sitter, I think it would benefit any potter to grab/borrow a pyrometer and graph the temp of your kiln during your firing, for a better understanding of what’s going on in. Better to do this before you have problems, so you have good a base line to start from.
What the hell happened in there?
