I want to build my own reclaimer, because i don't like the ones available. I was wondering if anyone could give me some insight by either measuring theirs(would require micrometer or calipers) or just their 2 cents(please clarify which type of insight it is). I am hoping i can get away with using the .035wall 1" ss304 tubes i already have. But looking at how the tubes in the top of my new lopi(not SS) Have sagged from my pyro fire making, make me wonder if .035 is thick enough, even though its just in the flue and not in the box. My Heat Reclaimer is going on a Sierra 8000TEC. Thanks. Great site btw.