Lift off style Raku kiln build
A suitable place was found in the kiln shed. The frame was built with " Unistrut" perforated steel for ease of construction. Cut and welded. Poultry screen was used to support the insulating fiber.
I made the actual frame of the kiln with perforated steel shelving("Kindorf")materials. This allowed me to bolt it together in virtually any size. An additional piece of angle is bolted to the side of the kiln frame. This piece is how the kiln stays is line as it is raised and lowered off the work in order to remove it. The unistrut is a channel so the kiln rides in between this channel.
In this photo you can see I used cinder blocks to raise the floor up a bit, then a hard brick floor is installed. I used 2" insulating fiber for the walls and roof.
The fiber was attached to the poultry screen using nichrome wire and three pointed kiln stilts. On the roof of the kiln I used stoneware clay disc's with holes in them to give additional support.
Another piece of perforated Kindorf shelf angle iron was bolted to the top. Steel cord was attached and then run through a pulley at the top to allow the kiln to be raised.
I used a steel bucket filled with brick and sand to act as the counter weight. The weight is the same as the kiln so it takes virtually no strength to raise and lower.
The burner is a small venturi atmospheric type with a flexible hose. Using the pressure directly from the tank regulator (approx. 6lb) the kiln can reach the proper temperature in a few hours. The tall vertical unistrut was cut to allow ease of removal of ware from the kiln.
First test fire.
I use fiber insulated pails for the local reduction. I had too many losses due to cracking at first with uninsulated reduction pails.
I line the inside and lid of the pails with fiber, then use chicken wire to keep the fiber in place. This has helped a lot especially with pieces that have wider bases.
I have two 4" x 4" flues out the top of the kiln, which gives a good draft to it. The kiln is set up to use 16" x 16" mullite shelves. In this photo you can see that I also used two layers of K23 soft brick for insulation which the kiln sets down on when lowered.
