#323 Rocket Stove J-tube construction wood burning

#323 Rocket Stove J-tube construction wood burning
Here’s how I cut and stacked my fire brick to create the J-tube and internal flue stack. Horizontal burn section is only 5.5″ long, 3.5″w, 3.25″h. Internal flue will be 3.5″x3.5″ inside, 24″h. Ratio of flue height to burn tube more than 4:1.

Here are the critical numbers…
* Tank is a salvaged 17gal compressor tank with 1/8″ thick walls, 36″ long by 12″ I.D.
* Vertical flue stack is 3 groups of 9″ long fire brick, 3.5″x3.5″x27″ (12.25 sq-in across, about the same as a 4″ round pipe).
* Vertical stack surrounded by 8″ x 24″ galvanized pipe with insulation stuffed in the open spaces.
* Gap at the top of the internal flue is 2″ from the center of the tank (A little less at the edges because of the convex surface).
* Gap between the 8″ pipe and I.D. of the tank is 2″.
* The horizontal burn tunnel is 5.5″ long (measured at the top edges), 3.5″W x 3.25″ H (11.375 sq-in across).
* Vertical feed tube is 3.5″W x 3.25″D x 7.75″H (measured from the top edge to bottom inside).

Many thanks to my Justin.tv regular nerd herd who helped greatly with small tips and suggestions along the way. Tippy4u, Critterwindow, Shubus, Adirondacks4me, Lwblack, Kane48, Outsider007 and many others.

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#323 Rocket Stove J-tube construction wood burning

16 thoughts on “#323 Rocket Stove J-tube construction wood burning”

  1. have you got approx dimensions for a 5 inch or a 6inch J tube, higher burning power but with same good smokless efficiency ?

  2. The problem I see with this setup is, as the wood burns-up, the ash that is created will build-up at the bottom of the feed area & burn tunnel causing a decrease in airflow. Am I wrong about this?

  3. You can use a 4.5-inch grinder also I use them all the time for cement board and brick and I would use Soapstone around this, not a steel barrel Soapstone holds heat much longer and you can get it thick of 3/4 inch thick and it is pretty

  4. I plan on using a stove similar to yours and put a cage around it and fill it with rocks for a sauna.
    Thanks for your lesson on brick plans. Jim

  5. the fact the firebricks insulate and reflect heat actually would cause a stronger draft, more than making up for aerodynamics and slight difference in size when compared to the a steal cylindrical pipe.

  6. Forgive me if I'm missing the point but why do you want to insulate the tank? I thought the reason for a rocket stove was to release heat or am I getting mixed up with a Rocket Mass Heater? Colin

  7. A 7" angle grinder with a 7" diamond masonry blade works better. If you take the guard off a 10" blade can be used but you have to be a little more careful. Wear steel toed boots so you can hold the brick down with your foot. This also works good when cutting fieldstone.

  8. Thanks so much for all of the measurements and ratios! That will help a lot. Due to cost, I won't be using fire brick. I have been looking into casting a rocket mass heater core out of sodium silicate and sand. Do you have any input/advice for this type of build?

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