Location: Southern alps, on the French side of the french /italian border 5000ft high Southern alpine climate.
posted 5 years ago
RJ, you can use prety much anything.
I've used 35kg gas bottles in my first and second build, about a foot in diameter, and about 4' high. I'm reusing thoses adapting my second build to run on bigger pipe. I've used a 500L watter tank for my batch rocket. I'm trying to get a rectangular box made, 20"x20" and 4' or 5' tall, so i can pile up bricks around, and have good contact. In the us, you could easily get air con square tubes. We've considered concrete suage pipes, well elements. Pozzolan chimney elements. Metallic lockers with the door and vents welded. Etc!
You can use a lot of things for the outside of the 1st bell and to build the 2nd bell. This is where the biggest cost are. I would recommend you stick with the 13x13 flue liners for the interior of the 1st bell. They are only about $22 for a 2 ft piece. So 4 pieces will run you less than $100. After the 1st bell interior the temperatures drop a lot, so your material choices increase. You can use brick, concrete, stone, attach cob to the outside etc. Just remember not to go too thick on the walls. It take at least an hour for every inch of material you add for the heat to migrate out.
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