I had afew hours to kill this mourning. This is a very worthwhile project to put together. It produces quite a bit of heat with comparably low fuel demand. Quite impressive actually. Mine produced more smoke, I didn't seal it up because the only thing I had around here was pea gravel. I'll replace the pea gravel w/ cobb or vermiculite, seal it up and it should be good to go.
YouTube - coffee can rocket stove
YouTube - coffee can rocket stove #2