- 1 used oil filter (previously cleaned and opened)
- 1.5 to 2 meters of thin copper tubing (outer diameter between 6 and 8 mm)
- Dry sand or coarse salt (acts as thermal insulation)
- Heat-resistant metal or ceramic base
- Heat source: This can be a flame (lighter, alcohol, gas) or an electrical resistance
- Optional: heating element or nichrome wire
Step-by-step preparation
Step 1: Filter preparation
Use an angle grinder or hacksaw to cut off the top of the oil filter. Then, remove the paper cartridge from inside and thoroughly clean the metal housing with a degreaser, followed by soap and water. Make sure to leave only the metal structure.
Step 2: Preparing the copper coil
Take the copper tubing and carefully coil it into a flat, spring-like spiral. The diameter of this spiral should be slightly smaller than the inside of the filter so it fits snugly. If you’re going to use it to heat air, seal one end of the tubing.
Stove assembly: two options
Option A – Thermal convection stove (without electricity)
- Insert the copper spiral inside the clean oil filter.
- Place the filter on a heat-resistant base, such as a firebrick or ceramic tile.
- Apply heat from below using a lighter, an alcohol candle, or a small gas burner.
- The copper will absorb and transmit the heat to the metal body of the filter, which will radiate the heat into the environment.
- For greater efficiency, you can place a small fan to disperse the hot air.
