Wood Firing Process Described
There seems to be an endless symphony of factors when firing a wood kiln. I feel lucky to participate & learn from Dan Barnett, who seems to have perfected the process; in regards to efficiency and sustainability, while keeping the treasured visual effects of wood firings in tact. All the while, he is making tweaks & learning from the process.
I want to preface this with stating that I am not an expert on wood firings but an enthused participant. Firing and glazing chemistry is something that has to be learned over decades & is something that one are never truly done learning.
My goal here is to give you a taste of the process, complications, challenges & beauty of this style of firing.
A little technical background/ context on kilns, firing types & my process can be found at the bottom of this page, if you are interested.
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Throughout the firing, we constantly stoak or feed wood to the kiln in order to raise its temperature.
There is a natural raise & fall in temperature that I think about like waves.
As the wood burns it creates gases that burn off and cycle through the kiln, creating this wave in temperature.
We track it both with a digital pyrometer and with cone packs to inform when and how much wood to add to the fire boxes.
Adding wood at the correct moment is crucial. If you add too much wood or add it too quickly, it gets overwhelmed. Not enough wood causes the box to go cold.
We use wood from dead or fallen trees on Dan’s property. They are split and dried for about a month. Primarily Oak but we use a bit of Pine that burns faster and hotter.
One of the markers of a wood fired pot is the slightly glossy & darkened spots. I call these marks of the flame. Near the end of the firing, we add soda and potassium carbonate to the kiln. As it vaporizes and moves through the kiln, it will leave marks on the pots. There are various methods to do this but we soaked wood in this mixture and added it to the fire boxes.
In order for all the work to get these special effects, there must be great flow in the kiln. Learning how the air and flames move is extremely important. Manipulating that flame starts when you are designing the kiln and informs how the kiln is loaded.
There are still many factors that I have not touched on such as, wind, change in atmosphere, how tightly the kiln is loaded, moister in the wood, ect...
I hope you find this interesting— Here’s to life long learning!
x Molly
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