Well, I wasn’t expecting this to happen, but the pizza kiln has turned into a fetish kiln, at least for the time being. Actually, budget fetish, since I couldn’t afford a nice black latex wrap…
Here’s what happened: We finally got the end of rainy season, and have been out working in the yard, finishing up various projects. I saw rain in the forecast for the next few days and decided to get the kiln finished and covered. Oh, and also the big pile of cob I have under the double tarp is starting to get stiffer from the sun, in spite of the good covering.
After digging into the pile of cob I found out that only the very top is getting stiffer, but I had started the job and decided to get something accomplished. After laying in the first 30cm or so, everything started to sag and the more I pushed it up, the more it would sag back down. Pretty soft. Well, I remembered I have a left over roll of plastic used to wrap palettes to keep the stacks from falling apart when the forklift manhandles them. So, I wrapped up the kiln starting with the base and working my way up over the cob. It really worked like a charm, and I was even able to push the material up and have it stay there, because the wrap is under quite a bit of tension. It is not very strong though, so what you see in the pictures is about 7 layers of wrap over the cob. Quite strong in layers.
I expect that the brick will absorb some water from the cob, and the summer heat will help some of that water out of the mix, making it stiff enough to start paddling in the next few days. If we paddle everything and get it nice and compressed over the course of the next few weeks, the worst of the cracking can be avoided. All that is left after that is to decide whether to leave it a simple dome, or add some sort of decorative motif. Oh, and bake pizza and bread.