I took a big coffee can, dremeled a vee about a third of the diameter of the can with the apex 2 inches above the bottom of the can. Opposite the vee, I punched 6 holes at the bottom with a church key. I took an old piece of rubber tubing and stuck a short metal cylinder on the end to create a blow-tube. It burns twigs, pine cones, cardboard, whatever. It contains the heat and makes the fire easier to start and easier to tend. It does not gasify, it does not fold up, and it lacks, shall we say, elegance. But it is cheap, lightweight, and requires little skill to create. I suspect that it performs about as well as the commercially available units. and lots better than an alcohol stove. It is a messy thing to carry around, but fits nicely in a USPS tyvek priority mail envelope, which those folks give away. Notice a theme here-I am thrifty. And unskilled. This thing suits me well.
(I am sure that the plan was on the Zen stove site, but cannot find it).
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Dance like you have never been hurt, work like no one is watching,love like you don't need the money.