The pocket rocket is a brilliant little invention that Ianto Evans and Larry Jacobs came up with some time in the late seventies, early eighties. (Yes, I did mention to Ianto that he might have thought of copyrighting that name before another, ahem, ‘invention’ made use of it. Hindsight, eh?) We built one for use in our sauna last year, to try out both earthbag building and rocket stoves at the same time. We went out in January to test how it would stand up to colder temperatures and within under ten minutes, we had raised the temperature from -15 C to +35 C, a 50 degree difference!
It requires only a few easily scavenged materials and is a great ‘starter project’. You’ll need a 30 or 55 gallon drum- one with a detachable clamp-on lid is great for a pocket rocket. And a couple of pieces of pipe- one for the feed tube and one for the chimney. That’s it. A little mortar for around the pipe and you’re ready to roll.
Start by burning off any paint on the barrel. We just stuck ours in our firepit and let it go for a while. While you’re waiting for the drum, cut two holes in the lid- one to fit each of the pipes. (Note: if you want to use the top of your stove for heating water, you’ll need to position those holes with enough room for a kettle or pot.) We didn’t cut our holes to the exact size of the pipe- we cut them slightly smaller and then cut tabs to fold up along the pipe for a nice snug fit.
When your barrel has cooled, dust off any remaining paint. Place your rocket stove somewhere away from anything flammable. (Seriously- this thing heats up like crazy!) Put the lid back onto the barrel and position your feed tube. It should be a few inches from the bottom of the barrel. Place your chimney in the other hole. The chimney (exhaust) only needs to go into the barrel a bit, several inches should do you.
The rocket stove prefers small diameter, straight wood. Gather some up and test drive! It’ll sound like a rocket when it fires up- that’s the draw. If it’s roaring when it starts- you’re good. Wait until it cools a bit and then mortar around the pipes. If you’re not getting the draw you want, fiddle with the feed tube a bit until you get it to just the right height. It may take a bit of patience, but this is a stove you can build in a matter of hours, so it’s worth playing around with to get just right.
Have fun- and let us know how it works out for you!
NOTE: If you want to preserve some of this heat, you could easily cob around the lower half or two thirds of the barrel. Otherwise, be prepared for some incredible radiant heat!
DISCLAIMER: This isn’t something you want to be building in your traditional home, as it would be a fire hazard.