DIY Rocket Stove Pool Heater Part 1

Steps

1. 1

   Step 1: Designing and cutting the metal pipe for the stove

   I start by using a 2-meter length of square metal tube with dimensions of 10 by 10 cm and a wall thickness of 3 mm. The fuel feed pipe is made from a 35 cm section cut at a 45-degree angle at the back, with a 10 by 10 cm piece removed from the back. I cut a hole 13 cm long and 10 cm wide at 65 cm from the bottom of the main tube, where the angled feed tube is welded on.

   What I used

   Item	Amount	Notes
   Square metal tube	2 meters	10 by 10 cm and 3 mm wall thickness

2. 2

   Step 2: Anatomy and fuel options of the rocket stove metal pipe

   Watch this part (1:06)

   The metal pipe serves as the main body of the rocket stove where fuel goes in. I can use wood, charcoal, briquettes, or pellets in it.

3. 3

   Step 3: How the rocket stove works by convection

   Watch this part (2:38)

   Wood falls into the pipe and is lit. Hot air rises through the chimney by convection, and new cool air is drawn in from the bottom.

4. 4

   Step 4: Combustion chamber temperature and glowing effect

   Watch this part (3:56)

   The combustion chamber gets extremely hot and glows red. It achieves high temperatures due to trapped heat, sufficient oxygen from two sides, and fuel.

5. 5

   Step 5: Efficiency and clean burning

   Watch this part (4:29)

   Efficient burning results in a longer burn time with less wood. There is very little smoke except when starting, and the stove burns very cleanly.

6. 6

   Step 6: Project plan and flame demonstration

   Watch this part (5:05)

   For this project, I plan to show how the stove burns in the videos. I will also show how flames shoot through the pipe.

7. 7

   Step 7: Detailed airflow and mechanism inside the stove

   Watch this part (6:41)

   Hot air rises in the chimney, and clean cool air is drawn in at the front. It takes a turn, meets the wood, burns, and continuously fans the fire via airflow.

8. 8

   Step 8: Adding the internal grate and temporary legs

   I weld a small grate inside the bottom of the upright chimney to prevent fuel from falling all the way down to the bottom. The main pipe remains open at the bottom to allow ash and embers to drop through. I also attach simple temporary legs to the bottom of the stove to keep it stable during testing.

9. 9

   Step 9: Temporary legs and plans for linking multiple stoves

   Watch this part (7:15)

   I added temporary simple legs for stability during testing. I have plans to potentially link two or three rocket stoves together in series.

10. 10

    Step 10: Preparing the spiro pipe mantle and painting

    I use a cheap 15 cm thick spiro pipe made of thin metal as an outer mantle to fit over the rocket stove. I cut a hole in it so it can slide around the fuel and oxygen pipes. Before sliding it over, I spray the rocket stove parts with heat-resistant paint.

    What I used

    Item	Amount	Notes
    Spiro pipe	1	15 cm thick thin metal pipe
    Heat-resistant paint	1	Used to spray the pipes

11. 11

    Step 11: Assembling and sealing the mantle with clay

    I screw the spiro pipe mantle onto the rocket stove and place a thin metal plate over the space between the air intake and fuel intake. I use clay from Action to fill all the gaps around the metal plates and seal the bottom. I then drive a few small screws into the bottom clay layer so the clay grips the metal koker tightly.

    What I used

    Item	Amount	Notes
    Clay	1	From Action, used to fill and seal gaps

12. 12

    Step 12: Smoothing edges and filling gaps with wetted clay

    Watch this part (13:07)

    I use wetted clay to fill gaps and edges for a smoother application. This helps seal the metal structure neatly.

13. 13

    Step 13: Insulating the chimney with perlite

    I put small wooden pieces inside the chimney to keep equal spaces and center the inner chimney inside the outer spiro pipe. I fill the cavity with perlite, which is extremely airy and lightweight, provides amazing insulation, and does not retain water like rock wool or glass wool. I pack and tamp the perlite down firmly with a piece of wood.

    What I used

    Item	Amount	Notes
    Perlite	1	Used as insulation

14. 14

    Step 14: Sealing the top and first test burn

    I seal the top of the mantle with clay, smoothing it out with wet fingers to keep dirt and rain out, and let it dry completely. For the first test fire, I place small thin pieces of wood and barbecue firelighters at the bottom and ignite them. Once burning, I fill the fuel tube with wood and close the flap, creating a strong suction sound from the airflow that gives the rocket stove its name.

    What I used

    Item	Amount	Notes
    Barbecue firelighters	Some	Used to light the fire
    Wood	Some	Small thin pieces and fuel wood

15. 15

    Step 15: Connecting to a continuous pool filter loop

    Watch this part (6:01)

    The system is connected to a sand filter pump with a continuous loop. Even a 1 or 2 degree temperature rise per pass heats the pool gradually over time.

16. 16

    Step 16: Takeaways

    • A rocket stove is easily made from a 2-meter length of 10x10 cm square metal tubing.

    • Perlite provides incredible insulation without holding onto water like mineral wool.

    • A small internal grate stops unburnt fuel from falling while letting ash drop out.

    • Closing the fuel flap forces air to draw from underneath, fanning the flame efficiently.

    • Part 2 will add water pipes through the chimney to connect the stove to the pool system.