This will be used to heat a 980 sq ft house. I have only built 1 heater, a 25 gal 6" with a 22 ft heatsink so far so fairly new to this.
Denzil Crews wrote: [...] the metal is approx 5/16th. I would think at the beginning of a burn cycle it would help cool downward gas faster, but retain more more heat later in the process. has anyone used heavyer outer skins and were there any changes or allowances needed because of the thicker metal.
I don't know the answer, but you're asking a very appropriate question. As far as I understand, the barrel or whatever-you-use-in-place-of-it is meant to be a 'heat-exchanger.' It helps to cool and shrink the hot gases and get them moving down and out of the system.
I've read posts by people who want to put cob all over the outside of their heat-exchange barrel. As far as I know, that is a very bad idea. However, the difference you're talking about (thin barrel-metal to 5/16th tank metal) does not seem as drastic as somebody putting cob all over their barrel-- so I don't know, you're tank may be fine; The difference may be negligible. Please do continue to look into it though; sounds like you're on the right track.
Another thing, you may already know: BE VERY CAREFUL CUTTING OLD PROPANE/GAS TANKS. ANY SMALL AMOUNT OF GAS LEFT IN THE TANK CAN MAKE THE PROCESS VERY DANGEROUS. There are processes for making sure its safe. There's a lot of information about such things all over the internet.
THE CAUTION ON CUTTING THE TANK IS!!! VERY IMPORTANT !
I live in southern Missouri near the Current river and have a neighbor that makes deep fryers out of the bell ends ofthe tanks, people here have fish frys along the river in giging season, he uses propane for fuel on the ones he builds. I've been trying to get him to build one on top of a rocket stove and finally this week he borrowed my RMH book to read.
He built a turntable with a mount for the plasma cutter, makes really clean cut. But anyone cutting one should always proceed with the thought it has residual gas in it or you could end up with fewer body parts or worse.
thanks again for the reply.