Theme Preview Rss

How To Make A Simple Wood Gas Stove (Large Version)

Wood Gas Stove -
Coaxial Downdraft Gasification 


This stove is based on the downdraft principle and typically built with nested cylinders which provides high efficiency in the burning process. Combustion from the top creates a gasification zone with the gas escaping downwards through ports located at the base of the burner chamber. The gas mixes with additional incoming air to provide a secondary burn. Most of the CO produced by gasification is oxidized to CO2 in the secondary combustion cycle, therefore gasification stoves carry lower health risks than conventional cooking fires.


Getting Started

Materials:
  •  (1) 4 Liter/ 1Gallon Paint Can - Plain, Unfilled Type ($3-$5)
  •  (1) 1 Liter Apple Juice Can ($1)
  •  (1) Adjustable Metal Hose Clamp ($1.50)
  •  (1) Printed Template Of Drill Holes (Optional) (Basically Free)

Tools:
  • Power Drill 
  • Step Drill Bit (1/16" to 3/4")
  • Sharpie Pen
  • Measuring Tape 
  • Can Opener (The One That Cuts On The Inside, Not Around The Outside)
  • Screw Driver or Driver Bit
Step 1 - Marking out the circles and cut lines on paint can lid

Take the lid of the paint can and use the apple can to trace out the centered position with your sharpie pen, like illustrated below. Now create a second circle inside the main circle you created with the apple juice can. Make this second circle smaller by 1/2" or 1-1/2cm.


Now draw lines connecting the circles together. Cut out the inner circle and then proceed to cut the lines up to the main circle. This with create tabs that will create a compression fit when we insert the apple can.

 Step 2 - Marking the drill holes in paint can & apple juice can, then drilling them out.


 You will only need to drill 14-3/4" holes just above the lip of the bottom of the paint can. You will need to use a step drill bit to cleanly achieve this. I recommend that you mark (14) 1-1/2" on center dots with your sharpie. This should give you approx 1/2" to 3/4" spacing between holes.





 Your holes should look something like this, these are 3/4" holes. I didn't measure exactly, so my spacing was off a little bit and this doesn't affect performance. 






You will need to take your can opener and open one end of the apple juice can, I would only use the can opener type that cuts open the top and not the side of the can, if you cut the side of the can you start to loose strength and can bend out of shape easily.

At the top of the apple juice can you will mark out  35-40 dots (1/16th drill bit holes) and mark them 1 inch down from the top to allow for the hose clamp and tabs from the paint can lid.








Now mark 8 dots (3/4 inch drill bit holes) spaced out approx 2 inches apart around the bottom side of the apple juice can.








You will need to make 60-80 dots (1/16th inch drill bit holes) on the bottom of the apple juice can. I wasn't able to make them perfect here but as long as you make a lot of them.








Step 3 - Putting It All Together

You will need to push the bottom end of the apple can through the top end of the paint can to make the tabs of the paint lid to catch and create the compression fit. You can do 1 of 2 things here, I seen people use cold weld compound to secure the lid to the apple juice can or like I did, I used a metal adjustable hose clamp. This way I don't have to worry about the compound break down over time or burning away after multiple uses at the camp site. Since the hose clamp is circular it holds the lid to the apple juice can very tightly and you can also swap out the apple juice can if it starts to get to rusty or fall apart after hundreds of burns.


After that you are pretty much ready to start your first fire in your new Wood Gas Stove!











You will need to hammer or pound in the lid to the paint can to securely fit into place.










 When you start to place your wood you want to layer them by thickness. Place thick sticks approx. 1 inch thick and 2 inches long on the bottom. Then the next layer of sticks should be only 1/4 inch thick and the rest small twigs. To achieve the best results do not fill above the holes at the top of the can. These are the jets for the wood gas to feed the fire.






You will need to just start your fire from the top and not from the bottom as the heat from the fire on top will help release the gas from the wood and help draw it through the top holes to efficiently burn the wood inside.  








As illustrated here you can start to see the wood gas coming through the top holes of the apple juice can.











Once you get the fire fully burning you will see all the jet holes burning nicely and effectively increasing the fire temperature and cleanly burning the smoke, wood gas and wood in your stove.  

   *******Notice Of First Time Burn********

Most paint cans these days come with a grey paint liner in them, so the first couple of burns you will need to burn off this grey liner and by doing so will produce a lot of black smoke. It took me approx three full burns to completely get rid of the liner. You may try to sand blast it off or use some kind of paint remover.


16 comments:

Brian said...

Great post and easy to follow steps/photos. So does this burn cleanly and leave no soot on your pot or does this still leave soot despite the secondary wood gas burn? I ask because in the past when I have made wood gasification stoves like this they have worked very efficiently but always sooted up my pots which I don't much like.

Hendrik Morkel said...

Nice post and MYOG guide!

Brian, also with this design you will most definitely have soot on your pot. I have used many different wood burning stoves and every single one of them leaves soot - it is a given with wood, just accept it and you're fine ;)

Bushman Joe said...

Brian,

Hendrik Morkel is right, you will get soot on the bottom of your pot. This Woodgas Stove does burn fairly clean and shouldn't produce as much soot versus an ordinary burn.

Also I forgot to add additional info on the first couple burns as most new paint cans come with grey liner in them these day and this will produce fair amount of black smoke or soot with the first couple burns, until the liner is fully burned off.

katty said...

I love the big stove specially because i like to cook all kind of recipe, how ever i prefer to have a reasonable place. Actually i saw a beautiful stove in a house that was published in costa rica homes for sale it was big and beautiful, i think i will go there because it catched my attention.

Shane said...

I used your instructions to make mine, they're great, thanks! One suggestion: use a one quart paint can instead of a one liter can. It's sturdier IMO, you can buy it as you buy the other can, and it's not as long as the one liter can. This allows for more draft getting under the burner can.

John said...

Shouldn't you have some kind of riser to sit atop the stove, so that there is air between the stove and the pot? With the current design it seems the pot would create a seal around the top of the stove.

Anonymous said...

John - I used PC board standoffs (20mm) and a fan grill from a PC cooling fan I had laying around. The fan grill screw legs are actually slightly curvy, so there's clearance over the screws. It'll screw into a paint can lid with a 4 inch diameter can in it. The second 4in can I used for the wind guard (20mm high, split along seam) pressure fits perfectly around the standoffs, and gives enough room for heat to get out.

Just waiting for JB weld to cure before I give it my first firing :D

hotels in indianapolis in said...

Interesting subject and well written. Love this great blog where i learn daily new things. keep posting such a nice post.

David Boevers said...

Any thoughts on using a wire platform just above the inner vessel's air-intake holes? I've found that tends to slow down the intakes getting clogged. Thoughts???

Also, what about using half of an IKEA ORDNING stainless steel caddy for a riser???

Srikanto Bormon said...

I needs to spend some time learning more or understanding more.
I would to share this: inventhistory
Clothing
Communication
Entertainment
Electric
Financial
Food Preparation
Green Technology
Software
Warfare
Transportation
Instruments
Office

Je Moeder said...

it works perfectly thanks for the instructions

Stringfellow573 said...

I love to camp and I will make a few to use and several to sell. This wood gas is similar to the plasma burning process of the sun.

renu soney said...

This site is good because they give us a new thing and new ideas and new topic how good all of they are we should appreciate them because of these good thing. . I know something information, to know you can click here
Air Conditioning Brisbane
Air Conditioning Installation Brisbane

Anonymous said...

So I've made two of these so far. One with the larger paint can and one with the smaller can where space is a consideration. They are great working stoves BUT....they are not really downdraft stoves. I'd argue that the air supply doesn't get pushed down from the top, but rather moves from the bottom up. Yes, there is a bit of gas being burned. But it's not really a downdraft.

james winney said...

In a gas cooker you will not find a fan to help distribute the heat evenly and therefore you will always find that the top of the cooker is hotter than the bottom.
Gas Cooker Installation
Thanks for sharing...!!!

james winney said...

These offer heat instantaneously and the flames touching and spreading round the bottom of your pans means the heat is evenly distributed across the hob ring...
Gas Oven Installations
Thanks for sharing...!!!

Post a Comment