First I should introduce myself I'm Derrick from upstate ny and have been looking threw the build threads here for a while built a double barrel smoker last winter and learned a lot using that and decided I wanted to build a reverse flow. A freind of mine owns a small junk yard and I found a old co2 tank in his yard was mounted to somthing at one time not sure what though. It's 200 gas 1/4 inch wall according to the tag. I do some repair work on cars he is selling and yard equipment and instead of asking for money he always takes care of me when I need something in the yard so the tank was free. I also picked up a wood stove a friends brother had that cost me a 30 rack of beer so 25 bucks. The doors have a couple small cracks but it should work fine for a fire box. If I cut the bump up on the top off its the just a little larger then the calculator called for and it's also made of 1/4 inch steel. I now need to find a trailer I have some creative ideas to try on that when I get one. so far i have 25 bucks invested plus diesel to go get them so far so good let me know what ya think good bad or indifferent.