http://www.davenportceramics.co.uk
http://simonwinder.com
This video shows how we made some pottery using the technique of sawdust firing. This is something you can easily do at home as it only requires a brick-lined hole in the ground to fire the pots.
The pots are made from Craft Crank, available in the UK at Potclay Ltd, a coarse grogged clay which resists shrinkage, but you can use a wide variety of clays with this method. The pots can be decorated with red iron oxide before firing, but the main coloration should come from the smoke during firing.
The fuel is a mixture of sawdust, small wood chips and shaving. Any wood will serve, but hard woods give a higher temperature. Avoid any mixture which may contain material from laminations. Our mix was obtained from the local coffin maker.
The kiln is simply a hole in the ground which we lined with old bricks. Don’t use metal in the construction as it will conduct the heat away. Also refactory bricks give higher temperatures because they are insulating. The lid was a slab of garden paving which rested directly on the brick lining.
We make our pots a day or two before the firing to allow them to dry out as much as possible before entering the kiln – if a pot feels cold to the touch it is still damp.
The evening after we judged the pot to be dry, we filled the bottom 4-5cm of the kiln with the fuel, then added a layer of pots. We tucked more fuel over and around the pots, leaving as few gaps as possible, but not packing too tightly – we want the fuel to burn slowly but we do need some air to circulate. We repeated this process until all the pots were loaded and the fuel reached almost to the rim of the kiln. We then topped up with more fuel, level with the kiln rim. We then built a pyramid of thin sticks of dry wood over the middle of the kiln, followed by an outer layer of thicker sticks until we had a pyramid 25-30cm high. We then set fire to this pyramid and sat back to watch it burn down. When the pyramid was reduced to a mound of gray hot ash we put the paving slab down on top of it, pressing the smoldering ash down into the kiln. The existence of a few bits of grit between the bricks and the paving slab provided enough ventilation to keep the kiln burning overnight. Ideally you ant to see the occasional wisp of smoke escape from the kiln.
The following morning all the fuel was consumed, leaving the pots in a pile of black ash. Wearing garden gloves, we carefully removed the pots, wiped off any encrusted ash and then polished them while still hot, using a soft cloth and wax polish. Smooth areas can be brought to a high polish if you are patient, but the secret is to ensure that the pots actually have a high polish before firing. To do this you need to polish the unfired pot to the best surface possible using the back of an old spoon or similar metal object.
The pots produced in this way are not resistant to dampness and will be fragile unless the shape is smoothly formed (e.g. egg shaped). To avoid this problem, you can fire your pots to 1000 degrees celsius in a conventional kiln before giving it the smoke treatment. This will give you a stronger pot, but you’ll have missed a lot of the fun.
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