Friday, April 22, 2011

Mini Rocket Stove

Finished Rocket Stove

In my spare time between classes at work, I decided to make a miniature rocket stove. Of course, I got it half done and put it on a shelf. That was a year ago. But yesterday I found it again, and decided to finish it up. So here is how I did it.

1. Tools and Materials 
    A. Can opener
    B. Tin Snips
    C. Two sizes of steel cans
    D. Clay soil
    E. Rice Hulls

I used two large baby formula cans, and five small coffee cans. It helps if the cans are designed to stack tightly on each other.

Cut the tops and bottoms off of all but one of the small cans, and one of the large cans.
Then cut a hole the size of the coffee cans near the bottom of the formula can with a bottom, and in one of the small cans. Another small can I cut to roughly match the curve of its mate. And yet another can I cut open and spread flat. That was for the tongue shaped piece called the fuel shelf that you can see above.

Gee... I hope you wore gloves to do that cutting....

Next, I put the cans together to form the feed tube (horizontal) and chimney (tall vertical). I taped the sections lightly together so they wouldn't fall off all the time.

Then I fit them into the large can, with the feed tube coming out of the hole.

After that, I put the shelf (tongue shaped flat piece) into the feed tube. It should rest about 2/3 the way to the bottom.
  The fuel- twigs or disposable chopsticks rescued from the restaurant next door- will lay on the shelf, and the tips will burn as air flows in from under the fuel shelf.

Almost ready. Now I needed some insulation. So I took some clay soil and water and made a clay slip. Basically clay and water you stir to the consistency of paint. I sprinkled rice hulls into the slip to coat them. You can use chopped straw if you don't have rice hulls. Or you can use both. Just make sure that all the pieces get coated.

I then stuffed the large can with the slip mix. You don't have to pack it too tight. After the bottom large can filled up, I put the second can (which has top and bottom cut off) on top of it. I made some triangular holes at the top with a churchkey can opener. That way I can rest a pot on top, and still let the gases escape.
Fill the can with slip up to the top of the chimney. My chimney was shorter than the height of the two large cans, but that is OK.

 And there you have it- a rocket stove.
How to light it?
Well this is my method.
1. Gather some twigs- from toothpick to thumb thickness.
2. light one or two very small pieces and gently lay them on the shelf. Add some more small pieces gently on top of them.
3. As the fire strengthens, add slightly larger pieces. Keep pushing the pieces towards the end of the fuel shelf. They will burn remarkably fast. There should be a considerable draft and a lot of heat with very little smoke from the chimney.

You can use this stove to boil water, or cook in a frying pan.  

Respect fire and stoves. 


  1. I did the same mini rocket stove as you, but man, the insulation precisely elevate the inside temperature and it seems that I easily reached 700 degrees Celsius as the bottom inside aluminium cans melted ! I wouldn't recommend this design...

  2. Man, this design is not working : you reach easily the aluminium cans melting point (that's the idea of insulation). It's probably working with traditional cans (iron) with 2 sizes