Over the past few months I've been developing a series of reconstruction illustrations to go with a set of archaeology toolkits planned as part of the Historic Environment Awareness Project. It's been a really useful time for my drawing practice; working out where to place figures on a stage where actors are far less important than the set, and of course learning vast amounts about various archaeological features. Various partners of the scheme as well as the project officer and county archaeologist have provided feedback on the drawings as they progressed, so they have undergone a series of permutations with an aim to chisel them into as accurate and relevant form as possible.
Anyway, the latest batch of working drawings is going off tomorrow and here is one of them; It's a charcoal hearth (or platform), that is the earthwork on which the wood is stacked. The platform is cut in to a slope and the spoil pulled out to form a level hearth.
As for a brief description of what is going on in the picture; Cord wood (that's regular lengths of seasoned wood, as opposed to "a cord of wood" which is 3.62 cubic metres of dry wood) has been stacked around a central flue which is held in place by a big post called "the motty peg" which itself surrounded by what looks like a Jenga set with all the middle bits taken out (obscured in this picture). Wet hay is heaped over the structure, followed by turves or riddled soil which will inhibit the flow of oxygen into the kiln. When all is ready the motty peg is removed and hot embers dropped down the flue which is then sealed at the top with more hay and turf, then the real work begins!
I have only done this on a small scale kiln, it took a group of about four people most of the day to set up so I imagine that using these traditional methods on a commercial scale must have been exhausting, regardless of the fact that you are required to basically stay up all night tending the clamp (this is a clamp kiln) as cracks and leaks can occur due to the intense internal heat and changes in shape - a charcoal clamp can shrink to as little as a third of its original size! Though I imagine this would be even less if you were inattentive and the whole thing burned to cinders.