Single bourry box kiln.............Q&A
I think that I am going to look into building the single bourry box kiln. It looks straight forward, and a good one for my first building experience. Do you have any suggestions or modifications that you would consider...seeing as you're the expert? What kind of bricks would you use? JV
You should not confuse a willingness to gather information and make it available on the Web with expertise, but thanks for the presumption. I have asked someone with experience with this kiln at the size in the plan and he has told me that it works well given sensible packing and firing. He did mention the possibility of dispensing with the bagwall completely. That being so I would suggest you build it exactly as in the plan, and experiment with the bagwall. If you change it around and you subsequently have difficulty firing it you won't know whether the blame yourself, the wood, the packing or the kiln. Sticking with a plan known to work will remove one variable.
You might want to vary it a bit to suit kiln shelves you already have, or if you intend to salt, to suit whatever size silicon carbide shelves you can buy. As far as I know silicon carbide shelves cannot be trimmed.
We have built wood kilns only for salting or for inefficient firings (anagama firings) for ash effects. Hence we have only used secondhand dense firebricks with fibre insulation on the outside in some places. If you can afford to use insulating bricks and are not doing salt or soda firings then by all means use hot face insulating firebricks on the hot face of the main chamber, and insulating bricks in the outer layer. The firebox and throat arch, exit flues and base of the chimney should be dense firebricks. Any old bricks will do higher up the chimney. If you intend to use soda or salt, use dense bricks, preferably high alumina ones, for the hot faces, with insulating bricks on the outer layer. People have used insulating firebricks on the hot faces of woodfired salt kilns, with suitable coatings, but I have no direct knowledge of this. Perhaps someone who has done this would like to tell us about their experiences.