Rocket (cook) stoves are as cheap and easy or as expensive and full on as you want them to be. Our first one was made using materials on hand: a coffee can, two progressively smaller cans, and a couple of handfuls of diatomite. It was never intended to be anything more than an experiment, as evidenced by the fact that I left it outside to rust for the last year, though it did come in handy when we lost power and wanted hot tea.
The basic idea behind the rocket stove is to use minimal (wood) fuel to heat a concentrated area. The stoves are generally meant for outdoor use as they don’t include a chimney. I did, however, find a video online for an industrial size rocket stove with a chimney and have posted it below. A person could scale down the design and make a reasonably sized rocket stove for indoor use based on that design.
For those of you who just want to get started though, and intend to use the stove outdoors, here is a list of what you’ll need: a large can, and two progressively smaller cans, some scrap metal, clay (optional), and some nonflammable material for insulation like industrial vermiculite, perlite, or diatomite.
For the sake of this article, I’ll assume you’re using a large coffee can for your main barrel. It’s the perfect size for a starter project. (Personally, I’m planning to use a 5 gallon canister for my next effort. I like the size of the surface.)
Basically what you’re looking to do is connect your two smaller cans so that they form an “L” shaped elbow and house this configuration inside of your largest canister. Insulation is packed inside the large can, keeping the heat isolated to the inner sleeve. Your wood is inserted in the horizontal portion of the elbow on a piece of metal used as a ledge.
Your smallest can needs both ends removed- easy enough with a can opener.
Then make a hole in your mid-sized can. You’ll want to make this on the lower portion of the can, right near the bottom, so that when you insert your smallest can, together they’ll form an elbow. You’re going to trace the hole to cut from your smallest can since that’s what it will need to fit.
Then take your biggest can and trace a hole in the side a couple of centimeters above the bottom using your smallest can. (I’m assuming you’re using a coffee can for your largest container, if you’re using something bigger adjust your measurements accordingly.)
On the lid of the coffee can, trace a circle the size of your medium can and cut this out.
Get your insulation ready. Use a light, non-flammable material such as vermiculite, perlite, scoria, diatomite or even wood ash.
Insert your medium can into larger so it is vertical with the open end up and the hole you cut facing the hole in the coffee can. Now insert the smallest can through the coffee can into the can in the middle. This will form the elbow within the coffee can. Pack underneath and around the elbow with insulation.
Now push the lid of the coffee can into the top of the coffee can until it rests on the top of the elbow inside. Be careful, there are sharp edges.
Finally, take a piece of metal scrap the width of the smallest can and insert it for use as a shelf for the fuel. You don’t need too long a piece and can even use the lid you removed earlier if you don’t have any scrap.
That’s how to make a very simple rocket stove. You can see that by applying the basic premises though, you can build a larger stove or a considerably more fashionable one with just a bit of effort. We went super lazy on our first one and it was still useful when push came to shove and we needed boiling water. I’ve posted a video of a considerably more polished version that I found on YouTube below.
Here is a video displaying two models that are very similar to our own first effort.
Finally, the video for the industrial size rocket stove with chimney. (Note: this is part 1 of 8 videos available in this instructional.)