I fashioned my first rocket stove out of three cinder blocks, a couple of chunks of paving slab, a rusty can, and a brick that I dug out of an industrial dump beside the Kalamazoo River. It was free, DIY, and as ugly as could be. My second rocket stove was made from the same materials, and wasn’t much prettier. But when it came time to feed a hungry crew of guerrilla gardeners, both stoves lit easily, burned hot, and used only a few sticks of wood apiece!
My experience isn’t surprising because rocket stove designers aim for nothing less than radical efficiency — the best of these stoves burn minimal wood and produce little ash, smoke, and excess heat. Rocket stoves achieve their efficiency with do-it-yourself simplicity rather than intricate engineering or expensive fabrication. This, too, is by intention: Ianto Evans and Larry Winiarski designed the first rocket stove in the 1980s for woodstove cooks across the developing world, where inefficient use of fuel wood often contributes to massive deforestation and pollution.
A rocket stove’s central “elbow” design is fundamental to its efficiency. Similar to traditional fireplaces, a rocket stove chimney, often called a “combustion chamber,” creates a draft, but the elbow moves the cooking surface upward (away from the fire and coals) onto the chimney’s vent. While this placement would cause problems for traditional stoves, the rocket stove produces minimal smoke. Rocket stoves pull an ample, oxygen-rich draft from below a fuel shelf into the horizontal section of the elbow, over hot coals, through the burning sticks, and up the combustion chamber to the cooking surface. While all rocket stove designs use the same basic elbow template, creative makers continue to push the limits of performance and efficiency with improved chamber insulation, more efficient fuel use, and higher burn temperatures. Have you wanted to discover how to build a rocket stove for your own homestead or back patio? Here are five rocket stove designs that anyone with basic DIY skills can make.
DIY Rocket Stove for Camping
John Fischer packs his portable rocket stove every time he hits the trails outside of the German city of Stuttgart. By designing a detachable feeding tube, combustion chamber, and grill grid, he produced a rocket camp stove that packs down just like his tent.
Materials: Large pressurized canister; 4 pieces of scrap metal for supply shaft; insert tray; 2 metal legs; 2 nuts, washers, and bolts; bolt with pointed head; short cable.
• Empty a pressurized canister completely and measure its length and diameter.
• Fashion a square supply shaft from scrap metal so the elbow “crook” allows for 1/4 inch to 1/2 inch on either side, and so the shaft is approximately 1/4 of the canister’s overall length.
• Cut off the canister’s top, and cut a hole the size of your wood supply shaft in the side.
• Fashion a supply-shaft insert, such as a cut HVAC vent cover or grilling tray, and place it into the vent at the bottom of the shaft to allow unobstructed airflow.
• Use nuts and bolts to fasten 2 support legs to the supply shaft’s end to create a slight feed angle and to correct for uneven terrain.
• Weld a long bolt with a pointed head to the bottom of the tank for added stability.
• Form the grill grate by notching 2 pieces of angle iron to fit together at a 90-degree angle.
• Cut the bottom corners of the grate to seat it within the combustion chamber.
• Paint the entire stove with high-heat paint.
• For additional stability, add a notch to the top of the feeding tube and to the corresponding side of the combustion chamber. Measure a short cable to cross that gap and secure with crimped cable ends.
‘Space Shuttle’ Cookstove
With little more than a welder and some scrap metal, Muhammet Sel fashioned a handsome rocket stove in Turkey. He’s dubbed the finished project the “Space Shuttle” because of its color, but also because of its impressive heat production. The design of this wood burning cookstove incorporates a 1-inch insulation sleeve, which Sel fills with soil.
Materials: 60-inch-long, 4-by-4-inch pipe; 29-by-4-inch, 16-gauge sheet metal.
• Cut a length of 4-by-4-inch square pipe into 2 equal sections at a 45-degree angle. One of these will serve as the supply shaft and the other as the combustion chamber.
• Cut a flat shelf for the supply shaft that runs along the pipe’s length to the short side of the angle.
• Weld the shelf to the supply shaft to partition off approximately 1/4 of the pipe for airflow.
• Weld the supply shaft to the combustion chamber to form a 90-degree angle.
• Attach a bottom plate that extends 1 to 2 inches beyond the combustion tube’s sides.
• Cut a front plate to fit around the supply shaft, and attach.
• Cut a back plate and 2 side plates that will fully enclose the combustion chamber. Attach.
• Fill the insulation area between the combustion chamber and the plates with soil or sand.
• Cut a top that encloses the insulation space, but leaves the combustion chamber clear.
• Smooth all of your welds with an angle grinder.
• Attach 3 or 4 solid bars with flat tops for cooking support. These bars should allow enough airflow beneath the cooking surface to maintain the draft.
• Apply a coat of high-heat paint.
Cinder Block Rocket Stove
Colleen Codekas’ take on the straightforward cinder block stove includes a sturdy foundation that would be at home in any backyard, fishing spot, or campsite. To cook on this utilitarian design, load wood into the vertical block’s top core (opening) and cook on the front core of the horizontal block.
Materials: 4 concrete pavers; 2 cinder blocks; brick; grill grate.
• Arrange 2 concrete pavers into a “T” to form the base of your stove.
• Lay 1 cinder block horizontally and stand another, vertically, on the pavers. Stand a brick on-end on top of the horizontal cinder block’s midsection. Square the joint.
• Stand 2 pavers on their edges on top of the base cinder block’s sidewalls. This should form an “H” when viewed from above (photo at far left).
• Top the “H” with the final cinder block (photo at near left).
• Place a grill grate across the top.
1-Hour British Brick Stove
Ravi Deo spent about an hour building this sturdy rocket stove in his suburban London backyard, but only because he wanted it completely level. If you’re not as particular, you could be grilling in a half-hour. This permanent setup is sure to be a hit at backyard cookouts.
Materials: Concrete paving slab; bricks; metal lath; grill or oven grate.
• Set a concrete paving slab (17 inches on each side or larger) so that the top is at ground level.
• Arrange bricks in a horseshoe shape on the slab, and lay metal lath on top.
• Add a second horseshoe layer, sandwiching the edges of the lath between the layers.
• Add a four-sided layer of bricks on top of the second horseshoe for the chimney base.
• Continue to add layers, alternating seams, to build the chimney to full height.
• Lay an old grill or oven grate on top.
Homestead ‘Popcorn’ Stove
Fred Erdmann’s rocket stove is a real “found materials” piece. The build begins with a popcorn can that, when filled with sand, gravel, or soil, provides more than enough insulation for full combustion. Erdmann’s rocket stove produces enough heat to boil vegetables or seafood on cold, wet nights at his coastal Washington-state homestead.
Materials: Large metal popcorn can with lid; 6-inch-diameter metal elbow; 6-inch-diameter stove pipe; metal screws or high-heat metal epoxy; grill grate; 3 or 4 legs.
• Cut two 6-inch holes into the popcorn can — 1 in the side for the elbow and 1 in the top for the stove pipe.
• Attach elbow to stove pipe with metal screws or high-heat metal epoxy.
• Fill the can with an insulation material (sand or soil).
• Fasten the lid to the can using metal screws or high-heat metal epoxy.
• Fashion a grill grate to lay across the hole in the lid.
• Cut a strip of metal, wrap the top lid, and fasten to form a wind block. (Optional)
To learn more about building this unique, inexpensive cooker, follow these instructions.