September 28, 2026 Post by : Editorial Wood-Fired Pottery

When I decided to fire with wood, I thought I needed a kiln the size of a shed. I was wrong. A small kiln — what some potters call a "fast-fire" or "train" kiln — can be built with a few hundred firebricks and a lot of patience. Mine fits in a corner of the yard, takes about six hours to fire, and gives me surfaces I could never get in an electric kiln.

The first thing to understand is that wood firing is not just about heat. It is about atmosphere. In a wood kiln, the flame moves through the chamber and around the pots. That flame carries ash, which melts and glazes the pots. It also creates a reducing atmosphere — meaning there is less oxygen than in a normal kiln — which changes how clay and glazes behave. Iron turns from red to green. Copper goes from green to red. It is alchemy.

Design and Materials

My kiln is a simple downdraft design. The firebox is at the front, the pots sit on a shelf in the middle, and the chimney is at the back. The flame comes in at the top, travels down through the pots, and exits at the bottom. This gives a longer flame path and more ash contact. I used insulating firebricks for the walls and a castable refractory for the arch. The whole thing sits on a concrete pad.

You do not need a perfect design. You need a design that draws well and holds heat. If the chimney is too short, you will not get enough draft. If the firebox is too small, you will not get enough heat. Start with a proven plan — there are many in books and online — and adjust as you go. My first kiln was ugly, but it fired.

Wood selection matters. Softwoods like pine burn hot and fast, which is good for the early part of the firing. Hardwoods like oak and maple burn longer and give a steadier heat. I use a mix. I also avoid treated wood, plywood, and anything with paint or glue. You do not want those fumes on your pots.

Firing and Patience

The firing itself is a long, slow conversation. You start with a small fire and gradually add wood. The kiln needs to climb slowly at first to avoid cracking the pots. Once it is above 1,000 degrees Fahrenheit, you can push harder. The whole process takes five to eight hours for a small kiln. You will need to stay with it, adding wood every few minutes, watching the color of the flame and the cones.

At the end, you shut the damper and let everything cool slowly. Do not open the kiln until it is completely cold. If you open it early, the pots will crack from thermal shock. I usually wait until the next morning. The reveal is the best part. You never know exactly what you will get. That is the magic and the frustration of wood firing. It is also why I keep doing it.

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