Making TLUD Stoves
This page gives instructions for making tlud stoves. For a description of how these stoves work, go to the ‘tlud stoves‘ page.
The Tin Can TLUD.
I have seen several variations on this theme, most slightly smaller than this stove and without the fan. I used a section of stainless steel pipe for the actual combustion chamber as it will not burn through in a hurry.
This stove demonstrates the principles of tlud stoves and can easily be scaled up to make stoves which burn for longer. Examples of other stove sizes are given following the tin can tlud building instructions.
The tin can tlud stove is pretty simple to make but you will need access to a mig welder and a small angle grinder.
It burns for 5 to 15 mins depending on stove size, hole sizes, fan power and fuel type and size.
It is good for first playing with biochar stoves as it can be made from scraps of metal and a small computer fan. You can improvise and use other items to make similar stoves. Bear in mind that the inner cylinder gets much hotter than the outer cylinder.
Welding very thin metal is not easy. The trick is to hold the welder on for the right amount of time (about a second), too long and it will burn through, too short and it will not penetrate.
How to make a simple tin can tlud stove.
1. Get a large tin can and cut a hole 5cm diameter in the wall.
Then cut the bottom off a small tin can, cut slits up from the bottom and bend the slits out as shown so that this can sits over the hole in the large tin can. Attach it by welding (not for the impatient!) or with heat resistant sealant such as gasket glue.
2. Then take a piece of pipe, ideally stainless steel which can take high temperatures, slightly shorter than the larger tin can and around 12 to 14 cm diameter. Spot weld a disc to the bottom of the pipe and cut a few thin air slots or holes in the disc.
3. Using an angle grinder with a 2mm thick disc, cut a series of slots every 5 cm or so around the rim of the pipe. These slots should be about 5mm deep. If they are cut at the angle shown by the pencil, the flame will spiral anti clockwise.
4, Cut a disc of thin steel slightly greater diameter than that of the larger tin can. Cut a hole in the middle of this disc slightly smaller diameter than the pipe, place the pipe upside down over the hole in this disc and spot weld the pipe to the disc as shown.
5. Turn the pipe upright, insert it into the centre of the large tin can, turn the whole thing upside down so that the disc on the pipe can also be welded to the rim of the tin can. (see also fig 6).
6. Bend a bit of steel and tack weld it on as a handle as shown.
Tack weld 3 strips of steel to the mouth of the small tin can as tabs to hold a small (12 v)computer fan in place. Insert the computer fan.
7. Weld 2 or 3 stands (about 8-10 cm high) to the top of the tlud as a pan/kettle holder.
Fill with dry sticks or wood chip, connect the fan to a 12v battery and light a little fire on top.
8. Put the kettle on and have a cup of tea.
When the flame dies down, empty out the biochar and quench it with water.
Now that you’ve got the basic principles and hopefully a stove that will boil a few litres of water, try scaling up and trying a few design variations.
Although it is fun to scale up, you get the most amazing looking fires and more biochar, remember that it is better to scale a stove to your requirements, ensuring maximum heat capture and a slower but steady flow of biochar going into your garden.
1. A wire mesh lid will give an increase in available heat.
2. A removable fan will last longer, it can be taken off when the stove is still hot but the fan has been turned off.
3. This stove has a combustion chamber 30cm deep and 17cm wide. It will burn hotter and for longer.
4. This stove also has a separate pipe to the primary (bottom) air intake. This pipe contains a butterfly valve. When fully closed all the air goes to the secondary air holes and when fully open the air goes to both air intakes.
It lights more easily when the valve is fully open.
Once the stove is burning well, the temperature (and accordingly the burn time) can be controlled to a surprising degree of accuracy by opening or closing this valve to varying degrees.
When the flame starts to diminish the valve can be fully closed in order to maximise the amount of biochar.
Reduced flame with valve closed.
Valve fully open, larger flame more suited for heating ovens or hot water cylinders.
5. This tlud has a 25cm deep and 20cm diameter combustion chamber.
6. A pan stand which reduces the flame exit has the effect of forcing the incoming secondary air into the wood gases more effectively.