I built my little bourry-box as a small test kiln so that I could fire samples of new rock glazes and also clays that I collected in different firing schedules than I use in my main wood kiln. Some of these firing produced good results, though all were interesting and allowed me to experiment far more than I would have been able without wasting a lot of materials and time. Particularly successful were the firings that I did to cone 6 with a reduction cooling. The high iron clays I used in these firings produced some amazing purple and red colours and surface crystallisation.While useful, the kiln had a few problems. The firebox design proved unsuitable. A Bourry box is stoked with wood up on hobs in the firebox, meaning that it must be cut to precise lengths. You can see the partly dismantled firebox in the image on the left. Because the wood I collect is scrap or unwanted, it is not possible to get enough that can be cut in this way
The image on the right shows the arch being taken down.
I also found the kiln too inefficient. It used around 1/2 as much wood to in a shorter firing than my main kiln, for around 1/8 the packing space. The chamber is simply too small for the mass of bricks used to build the kiln.
So..... I've been talking about rebuilding it for a couple of years and now, with all shows and exhibitions cancelled, I have the time to actually get on and do it. There are already a lot of second hand bricks in this kiln, which makes taking it apart much harder because of all the mortar used to make the bricks sit flush together. The dense bricks in the base are only 1 inch thick. I got them almost 20 years ago from a potter in Suffolk. The next kiln will be the third that they have been used in.
So what's the next kiln going to be? It's still on the drawing board but I'm planning a raised catenary arch chamber with a large open firebox area attached, where the wood will sit on hobs above a grate system. As always, I am aiming to maximise the effects of wood in the chamber, lots of ash and direct flame contact, in relatively short (and hopefully easy) firings.