Mode1: Wood Gas (12V Fan Forced TLUD)

As a continuation of my hobby of burning stuff in tins, this project arose from my fascination with wood gas TLUD (Top Lit Updraft) Stoves. I favoured the fan forced option (Mode 1), as it produces a very clean, hot burn with hardly any soot. But what if the fan batteries run out? Modes 2 and 3 use the chimney / potstand for either an alcohol or twig burning backup.

Due to the size / burn time, 3ModeStove Mini is intended as a camping / emergency use stove.

Apologies if this is very UK specific. I hope you can use some of the ideas anyway!

3ModeStove Mini Is Environmentally Friendly Because:

  • Does not burn fossil fuels which release carbon into the air.
  • Produces hardly any smoke into the air or soot on the pot.
  • Generates more heat from less wood by extracting and burning the wood gas.
  • Avoids cutting any live wood to burn, as it uses small twigs or other waste biomass as fuel.
  • Sequesters carbon from the atmosphere (albeit a tiny amount), leaving unburnt charcoal (biochar).
  • Batteries can be charged via domestic green electricity tariff; solar; wind; bike generator etc.
  • Uses recycled / saved / scavenged materials in its construction.

How Does It Work?

The fuel burns from the top down.

The burn chamber sits inside the stove body with a small air space between the two.
There are air holes in the bottom of the burn chamber (primary combustion).
The air holes you can see at the top of the burn chamber are for secondary combustion.

The burn chamber is filled with small twigs to just below the secondary air holes.
The fuel is lit on top with a small amount of accelerant (alcohol).
After a minute or so, when the flame bed is established, the fan is inserted and switched on.

The fan blows air into the primary holes, feeding the combustion from underneath.
The fuel burns with a restricted supply of oxygen, turning to charcoal and producing
lots of smoke (wood gas). The wood gas drifts up through the fuel.

The secondary air is heated as it is blown upward through the space between the
hot combustion chamber and stove body.
It exits the secondary air holes, mixes with the wood gas and together they burn!

It is a gas stove that extracts its own gas from wood, turning the wood to biochar in the process!

Step 1: Tools and Materials


Heinz Baked Beans can, half size
Diameter: 73.5mm

395 grams baked beans can x 2
Diameter: 73.5mm
(tapered, stackable base - see photo)
The lids from these cans
Pet food can cover to fit this size can

300 grams mushy peas can x 1
Diameter: 66mm

425 grams fruit cocktail can x 1
(+ 1 identical, if you want to make Modes 2 and 3 later)
Diameter: 85mm
(tapered, stackable base - see photo)

Drinks can
Duct tape

12V fan (mine is 40mm)
12V battery pack (I used 8 x 1.5V)

Cutting mat with grid, or graph paper
Awl or sharp file
Utility knife with plenty of spare blades
Sharp scissors (Leatherman Micra is great)
Drill with 4mm and 4.5mm bits

Great job - very useful!
Thanks, HollyMann!
Really cool, this is a great idea and im going to make one too
Cheers. Let me know if you try anything different that works out well. Input always welcome!
Elegant. Extremely well laid out. <br> <br>Hey, could put a potentiometer in line to control how fast the fan goes?
Thanks. That is an interesting idea for adjustable heat. You have got me thinking...

About This Instructable




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