methods

Working Methods

I biscuit fire all work in a programmable electric kiln. Much of my work over many years has been fired in a gas fired reduction kiln. I regularly build small kilns for salt/soda firings.

I have recently built a wood fired kiln(below)to a design I saw at a recent wood firing conference in Germany. It offers 12 cub ft of setting space and can be fired to C.10 in 8 hrs. by one person and in an urban environment with minimal smoke even in reduction.The kiln is very economical using about 1/2 cub meter (of dry wood!) to fire. The wood is sourced from my local mill at a cost of 5 euro per firing! The kiln will not give the classic wood fired finish because the firebox is under the floor. Because the chimney is contained within the kiln it does not need to be more than 18" above roof level. The roof can be flat top brick* or fibre like mine.

Update: I have fired this kiln 5 times and while it produced a few decent pots it has a wide temperature variation from front to back which I could not resolve. Based on my experience with the kiln I have now modified my larger gas kiln to fire with wood but retaining the burners for backup. I have fired this once with soda and got good pots all over.

This is the first kiln I've seen which offers wood firing as a truly viable alternative for the urban potter.

*(See 'The Art of Firing’ by Nils Lou for good info. on brick flat tops.)

Update on Phoenix wood kiln. 01/2012

I’ve fired the kiln now 6 times and have encountered persistent problems with temperature variation between front and back. Also I have found it difficult to get good reduction. This prompted me to try firing the work in saggars.

Overall my experience with the Phoenix kiln and the inexorable rise in the cost of gas suggested to me that I might be able to fire my larger gas kiln* with wood. I increased the width of the fireboxes and cut stokeholes into them from the front of the kiln. I also lined the fireboxes with high alumina castable and gave the kiln a coat of batt wash.This has been a great success and I have fired this kiln 3 times now with very good results. So long as the wood is well seasoned and not more than about 2”square the kiln will accommodate the wood and burn it efficiently. I’ve had no trouble with clinkering.

I fire the kiln to cone 10 in 12 hours. As always with wood kiln sourcing good wood is the key issue. At the moment I’m getting mine from a nearby sawmill. This wood is rubbish slats which require drying so I have to plan ahead. Joiners workshops might be a good source of ready-seasoned wood. Also I have to do some splitting but one meter cube (costing 5euro!) will give me at least 2 firings. Soda firings from this kiln have been better than those from gas. It seems that the wood flame is better at moving the vapours around. Postscript, 01/2012 I have recently returned to earthenware (see Gallery) and look forward to firing this new work in this kiln

* This kiln is a standard 20’cub. sprung arch kiln built from a design in “Building Pottery Equipment –Harvey and Kolb (Pitman) p.96