Building a Rocket Stove(mass heater/cooker) is an easy way to meet your neighbors, make dinner and stay warm!
Step 1: Tools & Materials
The 3 main materials you'll need to make your rocket stove mass heater/cooker are:
- a large diameter steel pipe with a wall thickness of 2-3mm
- one steel oil drum
- and one piece of steel round tube which can act to hold insulation around the combustion chamber (the center pipe)
Other than these materials you will also need a thick(2-3mm) piece of steel which can act as a lid for and maybe you will need additional scraps of steel.
Tools: this project can be done with just a hammer, drill and a grinder but we used a two welders(MIG & TIG), drill, plasma cutter, hammer and grinder.
Step 2: Cut Yourself a New Hole.
Cut off the Lid. You can do this by simply cutting it with an angle grinder or sanding the paint off with an angle grinder and then using a plasma cutter to cut around the rim of the oil drum.
Step 3: Drain It.
Drain any leftovers in your barrel and get it as clean as you can by adding sawdust and scraping.
Step 4: Cut Your Combustion Chamber.
You can make your combustion chamber in two ways:
Cut your pipe at a 45degree angle and weld the two pipes together to make an L bend.
Cut your length of pipe so that it is 60-70cm long at 90 degrees. Cut a square out of the pipe for feeding wood into it. Make a box out of sheet steel which fits cleanly onto the pipe and .weld it all together.
* the combustion chamber should have a shelf to sit the wood on allowing air to pass under the shelf and feed the burning wood. Only the tips of the wood should burn but there should be quite a bit of air flow so you don't want the shelf to extend into the combustion chamber but just to run for the length of the feeding tube.
Step 5: Insulation Divider.
So now you want to make the chamber which divides the insulation from the cool air flowing down the sides of the interior of the oil barrel.
Cut it to the same height of the combustion chamber and cut out a hole for the feeding tube to pass through. You don't need to weld the insulation chamber to the bottom of the oil drum but we did. However you can get it so that the insulation chamber keep the insulation contained and not flowing all over the inside of the barrel, and blocking the exhaust, do it that way.
Step 6: Exhaust.
Ok, so you've got all this heat and burning and combustion and while it doesn't produce much smoke it does produce hot Co2 flowing out as fast as the O2 can come in. What you need to do is cut a hold in the bottom of your barrel to allow this to come out at an equal rate to the air flowing in. If you can attach a mount on your oil barrel so that you can add a removable chimney, that would be preferred, but it's not necessary. W have our chimney running out of the rocket stove horizontally at a slight angle. One of these stoves we'd built has only about a meter of chimney exhausting onto our balcony with a chair directly over it - when the stove is running often people are sitting in the chair and pay no attention to it. Also with the air flowing
Step 7: Add Insulation!
Add insulation between your combustion pipe and insulation chamber. Whatever you can find to absorb and hold the heat being produced in the combustion chamber will work: broken bricks and tiles, gravel, rocks, vermiculite, etc.
Step 8: On Making Friends and Staying Warm.
Now it's time for a test run:
Chop some kindling sized pieces of wood and light a fire under them with some paper until they stay lit on their own. the stove may produce some smoke at first but once working properly not much will be flowing out of either end. the wood should go on the top shelf of the feeding tube allowing air to flow underneath to ignite the tips. after a few minutes the cooking surface will get hot and you can begin cooking: stir-fry's, hash browns or cottage fried potatoes, curries, barbecue, fish, rise, pasta...
People are drawn to the smells coming from the rocket stove: the burning wood and caramelized veggies.
Have a great dinner with them, talk, make friends/future friends and stay warm.
*we put this rocket stove on a pallet for ease of transportation and increased air flow which was a bad idea because our rocket stove got too hot even on the bottom so that it charred and smoked the palled but also because bits of coal falling through the combustion chamber (we left a hole in the bottom for added air flow as an experiment) would set the pallet on fire.