Mini Rocket

Hello

I'm planning on building this small oven heated by a rocket stove wrapped around it.
Dimensions:
1. Y-shaped burner made from 4x4 steel tube.
2. 4x2 inch C- channel section welded around the oven as shown. Total length is approx 1.2m or 4ft.

Then, I hope to later add a BBQ grill that is to be indirectly heated by the exhaust from the oven.
Finally, I intend to insulate the whole assembly with an adobe-wood chip 50/50 mix.

I'm new to rocket stoves and I'm working off YouTube videos I've watched.
Will this work? Are the cross-sectional areas and the length sufficient for this to heat the oven?

Thanks in advance.
PS: design pictures attached

Hi Ronnie;
Welcome to Permies!
Looking over your design I am assuming this is all built with metal.
From your drawings, it appears you wrap the exhaust channel around one side and across the top of the oven to your chimney.
I suggest, routing your channel on both sides of the oven box and starting your vertical chimney in the center over the oven.
This should give you a more uniform heat inside the oven.

I'd like to point out that over time your metal will degrade and eventually start leaking exhaust into your building.
Solid clay bricks are the building material of choice.
A benefit of building with brick is it holds the heat much longer than metal will.
Insulating cob made from clay and straw is also the most used for ovens.

Thanks for responding Thomas.

I'd initially designed it to wrap around the oven, then I realized that the exhaust was over 2m long and got worried that it wouldn't burn well. So I reduced the turns.

Honestly, I'd rather use clay all through because I have good clay here. I just don't know how to form it around the oven. Also, I don't want smoke in the oven because I hope to bake more than just bread and pizzas.

Thanks again

Hi Ronnie;
With an open rocket stove, rather than a rocket mass heater I would not expect to have any draft issues after it is warmed up.

Do a test, tack weld a test unit. First, build it with one vertical, and then add a second to see if you have any issues with it drawing.

I predict that it will work very well on both sides and the vertical chimney directly over the oven box.

My impression from your drawings is that the oven gets no smoke only the radiated heat off the channels.

Clay/sand mixed with straw or a similar material is called insulating cob and it is a fine choice to use.

Thanks. I'll try that.

My feeling is that a 4" rocket stove is not likely to put out enough heat fast enough to bring a usable-size oven to baking temperature, especially with only a 4" wide strip of heating surface passing around it.

By far the best way to make a white oven as you desire would be to make the metal box as you show, then a masonry or cob combustion core with its exhaust going up to a narrow (say 2" or so) space almost completely surrounding the oven, then collecting to go to the chimney. Everything but the box can be masonry; brick would be most durable for the fire feed area, but the rest can all be formed from cob at least several inches thick.

Thanks Glenn, I'm beginning to realize that.
Would you recommend a 6x6 inch firebox and riser.

Also, I'm glad to hear that cob is safe for this application. I'll go for it. I hope you mean cob with straw since I already intend to use it for insulation.
I want to use cardboard as forms around the oven box.

Finally, should the fire box be centered under the oven arrangement? Or any will location (frontish) do? And, how high for the riser?

Thanks in advance.

There will be a huge difference between a 4” steel stove and an insulated 6” refractory stove.
However the riser needs to be longer and that could make  the oven quite high from the ground.
Here is my own 6” J showing how well they can work…..

I Appreciate the ideas. Let me see how to drop it further. I was hoping to have the ashes fall into a collection area below the burner. I'll see how to go about it another way.