Making a rocket stove - help!

Glenn Herbert wrote:If you are making a permanent installation outdoors, or can sink part of the core below floor level, a J-tube would work excellently for a cookstove. An L-tube would require bending down to check the fire and feed it unless the top is higher than you would want.


Granite would crack very quickly from the extreme concentrated heat. It can stand a lot of heat, but not uneven heat.

Can someone help me i cant make a rocket stove at all. Im now trying the j style and no luck. Dimesnsions are 7:14:28

Hi Eric - Welcome to Permies!
Can you describe the problem you are having? If I were to guess as an inexperienced stove tinkerer, I would say that your stove is not rocketing because the riser is not insulated.

Nancy Reading wrote:Hi Eric - Welcome to Permies!
Can you describe the problem you are having? If I were to guess as an inexperienced stove tinkerer, I would say that your stove is not rocketing because the riser is not insulated.

How can i insulate it and still take it camping?

Eric Champlin wrote:

Nancy Reading wrote:Hi Eric - Welcome to Permies!
Can you describe the problem you are having? If I were to guess as an inexperienced stove tinkerer, I would say that your stove is not rocketing because the riser is not insulated.

How can i insulate it and still take it camping?

Could i weld some steel to the steel to make it double thick?

Hello Eric!

What is the spalling temperature of the metal you are using?  

Usually we make the rocket stoves out of refractory materials because they get well over 1000 degrees.

Samantha Lewis wrote:Hello Eric!

What is the spalling temperature of the metal you are using?  

Usually we make the rocket stoves out of refractory materials because they get well over 1000 degrees.

Im not sure. Its 3/16ths inch thick. I dnt care if it burns up really. I just wanna see some action ya know

Eric Champlin wrote:How can i insulate it and still take it camping?

Could i weld some steel to the steel to make it double thick?

It's not going to be very efficient I suspect, but making a twin wall over the horizontal channel and riser might help - like a twin wall flue. I would think about putting some perlite or similar insulation in there though, since internal convection would soon cool it down. Wrapping in a heat insulating material might be simpler, especially if you don't require it to work for a long time. I think you need the riser to be more insulated than the burn tunnel so that reduces the risk of the burn tunnel acting as the chimney!
You may be better off looking at metal camping stove designs though, rather than rocket stoves. Try this thread about travelling rocket stoves. It may give some more pointers for you.

If you are concerned about damaging insulation during transport, I would advise making a sheetmetal wrapper with an inch or so of space around the burn tunnel and riser, and filling that with insulation. Coarse perlite mixed with a tiny bit of powdered clay and moistened would hold its shape and not spill out of gaps. Maybe you could pour perlite into the gap, then drench it with muddy clayey water and let that dry out with some heat... I haven't tried this so don't know how well it would work. If you add standoffs to keep the wrapper evenly spaced from the core, fiberglass or rockwool would work fine.


Note: an easy way to make a wrapper would be to put some 6" galvanized duct around the 4" steel core. This would give the most insulation at the flat sides which will get hottest, and be safe and easy to move around.