Rod Bumstead

The inner barrel and outer barrel will be welded together at the bottom with 4 pieces of 4" x 25" piece of bar stock. So, when the combusted gases exit the heat riser they will be trapped between the two barrels with only one way to go, through the transition zone and into the flue pipe. I am thinking of using a 10" flue pipe which will pass through a river rock raised mass before exiting via the house chimney. We will need to reinforce the basement joists for the mass unit. The rocket heater will not be that heavy - I am guessing 350 lbs. see the attached picture for the progress. I am redesigning the combustion unit so it is missing from the photo.

Thank for your answers Thomas... I have updated my profile as suggested.

... Yes, I do have a copy of the book. I picked it up at the university of Guelph organic conference last February.

I can include plans to incorporate a "top of barrel" gap to 2" , and increase the barrel to barrel gap to 3".

I was thinking an 8" pipe through the mass would be best....

I ran a test burn last night with just the burn chamber and everything worked good ...

I am setting this up as a portable unit also ... A base has already been welded up with a raised carriage to hold the burn tunnel and heat riser above the base . I will be putting insulation under the burn tunnel.

Rod

I would like to build a unit with a square barrel... i.e. home made barrel, made with 1" angle and sheet metal (18 ga.). Does anyone know of a problem with such a design.

The heat riser will be square fire brick with a square insulating can. Then a square radiant can over top with a gap of 1.5 inches between the two cans. The burn chamber is about 6.75 inches square from entry to the top of the heat riser. The gap btw the heat riser and outer can is two inches.

Cheers...
Rod

I would like to build a unit with a square barrel... Ie home made with angle and sheet steel. Does anyone know of a problem with such a design. The heat riser will be square fire brick with a square insulating can. Then a square radiant can over top with a gap of 1.5 inches between the two cans. The burn chamber is about 6.75 inches square from entry to the top of the heat riser. The gap btw the heat riser and outer can is two inches.
Cheers...
Rod