Wednesday, January 12, 2011

How to Build a Rocket Stove

A rocket stove is a simple wood-burning stove that can be easily constructed out of inexpensive or salvaged materials. Rocket stoves are often (although not always) portable stoves. They can be used in emergencies or as alternatives to conventional stoves both at home and outdoors. The design is very basic: fuel is fed into an opening at the base of the stove, a fire burns in the center of the stove, and heat is directed to the top of the stove through a chimney, atop of which food is cooked. Rocket stoves come in all shapes and sizes and can serve many purposes. Instructions for building a rocket stove are numerous, and designs can be very simplistic or quite complicated. The rocket stove that I built was a combination of several plans, including a few innovations of my own. Thus, the instructions that follow should not be considered the rule. Feel free to make your own modifications as necessary. In my opinion, rocket stoves should be built as cheaply as possible. So, I’m sure you can do much better than I did.

-tin snips
-drill and drill bit (of any suitable size)
-pencil (or some kind of marking device)
-whatever else you think you might need to get the job done

-mini-keg (aka party keg)
-4 inch stove pipe elbow
-4 inch to 3 inch stove pipe reducer
-aluminum foil or wood ash
-stove grate (or rack of some sort)

Start by removing the top of the mini-keg. This can be done by drilling a few holes in the top to give you a starting point. Then, using tin snips, cut from your starting point around the sides until the top of the mini-keg is open. This may result in jagged edges around the sides, so use pliers to press them down, otherwise you might end up cutting yourself later.
Next you will need to make a hole at the base for the air-intake and fuel feed. Since it’s a mini-keg, the ideal place to make the hole for this would be around the tap. Use the 4 inch end of the stove pipe reducer to trace a circle around the tap. Again, use the drill to make a few holes and the tin snips to cut out the circle.
Now you will need to begin insulating the inside of the stove. This can be done with aluminum foil or wood ash or some other material that doesn’t conduct heat. I used aluminum foil. First, create a good base. I did this by taking small folded up pieces of aluminum foil and pressing them down with the blunt end of an old axe handle. After you have a short base, fit the elbow through the lower hole, making sure that your chimney will be centered inside the mini-keg, then continue packing the aluminum foil around the elbow.
Eventually, the elbow should be packed in pretty tight. At this point, you will need to fit the stove pipe reducer on the end of the elbow to complete the chimney. The top of the reducer will likely be sticking out of the mini-keg, so you will need to cut it so that it’s flush. Do this by drawing a line around the stove pipe reducer (while it’s fitted on the elbow) even with the top of the mini-keg, and then use tin snips to cut off the excess pipe (you might be able to cut it off with a hacksaw as well). Once the reducer is fitted on the elbow and the chimney is flush with the top of the mini-keg, continue packing in the insulation material until you reach the top.
Now you will need to find a stove grate or a rack of some sort to place on the top of your stove so that you can steady a pot above the chimney. Luckily, I have an old gas stove in my apartment, so I just used a grate from that. Once you have a grate, you are ready to fire up your stove and cook your next meal.

The cooking process is quite simple. Feed small pieces of wood into the base of the stove and light them on fire. Place whatever you are cooking in a small pot on the rack above the chimney. Continue to fuel the fire for as long as necessary. Eventually, your meal will be ready to eat.
One thing I noticed about this design was that the inside of the stove pipe elbow didn’t really have a nice, even surface on which to place wood, so I folded up a large section of aluminum foil and used it to line the bottom of the stove pipe. It seemed to work pretty well; however, you might have an even better solution for this minor design flaw.


Maaike said...

This is sweet! I definitely want you around when the apocalypse comes!

Eric said...

Cut open and flatten a tomato can, and lay that inside the feed pipe. It will be a shelf that the sticks rest on, while the air freely flows under it.

John said...

Made from a German mini 'bierfass' (beer keg) and my favorite beer! Five liters...

Unknown said...

Neat stove. One comment, don't use galvanized pipe for the stack or elbow. Galvanizing will out gas when heated. Instead use wood burning non-galvanized stove pipe.

The big box stores sell it.