A 200-litre (55-gallon) steel drum can be the body of a large rocket stove: a 15 cm metal riser pipe goes vertically through the top, a horizontal feed tube enters near the bottom, and insulation fills the space between pipe and drum. The drum top becomes a large cooking surface. Never cut, weld or heat a drum that has held fuel or chemicals, because residue and vapour can explode or give off toxic fumes.
Part of Rocket Stove Design
A 200-litre steel drum can house a large rocket stove with a flat cooking top. Its danger is its history: a drum that held fuel or chemicals can explode when cut or heated.
A Drum Gives Area, Not Draft
The overview calls a 200-liter / 55-gallon drum an excellent rocket stove body and describes the build:
- Insert a 15 cm metal pipe vertically through the top as the riser.
- Connect a horizontal feed tube through the side near the bottom.
- Fill the space between pipe and drum with insulation.
- The drum top becomes a large, flat cooking surface.
- The design can heat a large pot, a flat griddle or even an oven chamber.
The 15 cm riser has a bore of π × 7.5² ≈ 177 cm². The overview does not say where the exhaust leaves the drum, which is the part that decides whether the stove works. Whatever route you build must keep the flow area at least as large as the riser’s bore and give the gas a clear way out, so the draft is not choked; see The Chimney Effect. Check it by running a small fire and watching for smoke at the feed opening.
Choosing And Preparing A Drum
- Know what it held. A drum that held fuel, solvent or chemicals retains vapour and residue.
- Fill it with water before cutting. Cut a drum that has held any flammable only with it full of water, and only if you are sure the contents were not toxic. If in doubt, choose another drum.
- Avoid galvanised and painted drums unless the coating is burned off outdoors.
- Remove sharp edges and mount on bricks so it cannot tip.
Common Mistakes
- Cutting a closed drum with a spark-making tool. Vapour explodes.
- Hot-plate burns. The whole top is a cooking surface at a few hundred degrees; mark it hot.
- No insulation around the riser. The flame cools and smokes.
Safety
Drum explosions and a hot top
Residual fuel vapour inside a drum ignites from a single spark or cutting flame. A drum stove that smokes through leaks or a blocked exhaust produces carbon monoxide, which has no smell. Use outdoors or pipe the exhaust out of the building. See Carbon Monoxide Risks.
What’s Next
- Learn next: Multi-Pot — feeding a group
- Combine with: Insulated Burn Chamber — what fills the drum