My design conundrum: what for the inside plate/tube? What for the outside container/plate? i just found a large stock of big aluminum tubing. It was a three piece flagpole kit. Makes me think i should make the container out of PVC tubing as there is no readily available caps for 2.5 to 3" aluminum tubing. I'm also thinking coppertubing inside the Al. Probably too much distance between plates for good current production. I can find copper caps easily enough. i should probably just take that step first, and if the results are encouraging proceed from there.
Thanks for the help!