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DIY wood gasification stove.

Discussion in 'Self-made Gear' started by Valcas1, Dec 14, 2009.

  1. Valcas1

    Valcas1 Scout

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    I posted this on another forum and it was well received, so i figured I would post it here as well.

    I bought a 1qt paint can from my local Ace hardware. $1.99 this one happened to be unlined which is what you want. If you can only get the epoxy lined ones just make sure you burn it real good before cooking.

    [​IMG]

    This is not my idea but I was told that a Progresso soup can will by friction into the inner lip of the paint can. So a can of Chickarina soup was in order for lunch and I now have this.

    [​IMG]

    I cut the bottom of the paint can out with a regular hand held can opener. Some online research says use a safety cutter but I didn't. I think the only benefit from using a safety cutter is you get a bottom that can be put down as to not scorch the ground.

    Now we have to put holes around the top to allow for the draft between the two cans.

    I used a Irwin step drill bit. as seen is this picture

    [​IMG]

    You can see how I laid out by vent holes on a piece of paper aand simply taped it to the can as a guide. I went with holes around the top of 3/8" about 1" apart on center.
    [​IMG]

    I am sorry I dont have pictures of this step but you need to put a second series of holes around the base of the inner can. I again used 3/8" and drilled them low on the can.

    Now take your paint can that you have cut the bottom out and drill 1/2" holes around the base so that you can draw air in and up the side walls between the cans. I started with 4. I figured you can always drill more if needed. I am still trying to fine tune this part.

    Now press you inner can into the inner lip of your paint can from below. It is a perfect fit and will take some pressure to get the inner soup can to seat well.

    Looking into the the cans it will look like this.
    [​IMG]

    In the last picture you can see the 1/2" hardware mesh fire grate I made to lift the bottom of my wood off the bottom of the can and over the top of the lower holes.

    Final picture is of the stove after several burns. I am experimenting with different pot stands now and will update my findings as I progress.

    [​IMG]

    [​IMG]

    To be continued...
     
  2. Valcas1

    Valcas1 Scout

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    Burn photos...

    These stoves are designed to burn from the top down so I figured I would show you how I set mine up to light and make some boiled water.

    First here is my fuel. As you can see it isn't much more than twigs and pencil sized sticks. There were four small pieces of wood that were thumb sized I put in first.
    [​IMG]

    [​IMG]

    Fully loaded and a few slivers of fatwood for starting.
    [​IMG]

    Starting to burn.
    [​IMG]

    good burn going now.
    [​IMG]

    No smoke, but lots of heat for that little bit of wood.
    [​IMG]

    Not sure if you can see how it is burning the wood gas in this picture I tried to show it but not sure if I pulled it off.
    [​IMG]

    Cool enough after burning for 15 mintues to do this.
    [​IMG]

    Ended up with this.
    [​IMG]
     
  3. Valcas1

    Valcas1 Scout

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    With alky penny stove.

    I was thinking about using a alky stove in my new wood gasification stove. So here are some brief test burns tonight.

    First is the penny stove along with the wood burner and one 35mm film container full of alcohol.
    [​IMG]

    Filled the stove with alcohol and dropped it into the wood stove and tried to fire it up.
    [​IMG]

    Found out that the stove needed a priming pan to charge up and start to pressurize so this is the stove with some aluminum foil under it for a priming pan.
    [​IMG]

    Starting to pressurize.
    [​IMG]

    16 oz. of water in my sonpeak ti solo cup. and put on the burner.
    [​IMG]

    Look at that burn pattern beautiful.
    [​IMG]

    [​IMG]

    Slightly over 4 minute later we have this.
    [​IMG]

    Here are my observations. The alky stove was not burning blue flames as usual. If you look at the pictures it actually looks like it is getting some benefit from the down draft of the wood gasafication stove. 16 oz. of water in under 5 minutes is impressive to me. I am really liking this stove. I would imagine that with 2.oz of alcohol I would be able to cook eggs for breakfast on this thing with a pan. I believe I am getting all the BTU's out fo this setup.

    I must say I am just starting t play with diffeent combinations for stoves but so far this little set up is promising

    Let me know if anyone would like to do a bit of trading, custom wood gas stove for who knows???
     
    Last edited: Dec 14, 2009
  4. GreyOne

    GreyOne Elder Lifetime Supporter

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  5. skw

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    Nice stove! Thanks for sharing.
    Matt
     
  6. Valcas1

    Valcas1 Scout

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    Greyone I would be more than happy to do that, if I knew how.
     
  7. Big K

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    Really nice stove you made there.
     
  8. skw

    skw Scout

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    Just post reply in thread "Camp Gear Under 100 dollars" with URL of this tutorial ;)
     
  9. Valcas1

    Valcas1 Scout

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    Gotcha! Will do.

    Paul
     
  10. Grits

    Grits Guide

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    Boiling 16 ozs in under 5 mins. is impressive indeed! Plus, primary purpose as a wood stove!

    Does the paint can lid still fit on the can once you've modified it?
     
  11. Valcas1

    Valcas1 Scout

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    That is a great question Dr. Believe it or not I have not tried. I will have to see tonight and get back to you. I am thinking that it will not becasue of the way the soup can nests into the innder lip of the paint can. I will advise at a later date.
     
  12. moose

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    great test and tutorial, love the shots and the stove rocks. well done.
     
  13. smokechoker19

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    Valcas1, great post. I make a similar stove. Mine has about 1 1/2 hole in lower side that i can continually feed more wood as needed, the hole is about 1 1/2 inch above bottom and I put # 8 copper wire in the sides all way across to to other side you can use heavy galvanized wire instead of copper. When wire is clear through bend sides down wont come out. After the 2 cross wire together in middle for stability. With the crossed wires you can put up inside and sides will support cup on sides. drill several 1/2 inch holes about 2 inches from bottom for air. works great. When done cooking let cool and dump ashes and away you go.

    Smoke
     
  14. Valcas1

    Valcas1 Scout

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    Just wanted to report the lid does fit on the paint can.
     
  15. Pawoodsman

    Pawoodsman Guide

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    Awesome tutorial thanks for sharing
     
  16. Grits

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    Many thanks! That is quite convenient, then!
     
  17. Ursinos

    Ursinos Guide

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    Can anyone give me links regarding how these stoves actually work? I'm trying to figure out what they actually do differently than just a hobo stove. All I'm finding when I search is people showing theirs off, or showing out to make them.
     
  18. Trekon86

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    Bear,
    I think they burn from the top down, e.g. you load them in the center of the top of the inside can and light it underneath, and it burns efficiently because the hot air rushes up between the can and burns the "wood gas" which naturally occurs in the twigs.
    So basically, you get the benefit of a woodburning stove without the smudgepot effect. (no smoke).
    PMZ
     
  19. GrouchyBear

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    Impressive use of simple materials - maximum utilization of fuel - great job all around.
     
  20. Ursinos

    Ursinos Guide

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    LoL, my mind has way too much of a scientific bend to it, I see things like this, and want to understand the science behind it. Is it a case of the fire causing the air to heat up and move through the space between the cans thereby feeding more oxygen to the combustion process and giving a cleaner burn? or is it something else?
     
  21. Trekon86

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    I think that's it...err...yes I do believe so:p
    PMZ
     
  22. Ursinos

    Ursinos Guide

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    Bingo, yay wikipedia. shoulda looked there first.

    As the fire burns in this configuration, it produces a biogas fuel. The design of the burn box means that air is being drawn in from the top, pushing the gas downward until it hits the vent holes that allow it to escape upwards to be fed back into the firebox area (bringing in more air with it as it moves). If I understand this correctly, it works kind of like the afterburner on a jet. The gas is already preheated so when it ignites, it burns almost completely and at an even higher temperature.

    Here's a diagram for any of you geeks out there like me lol

    http://en.wikipedia.org/wiki/File:Wood_gas_stove_Principle_of_operation.png
     
  23. Homeslice

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    Had my Progresso for lunch today, hitting the hardware store tomorrow for the paint can. Thanks again for the writeup.
     
  24. OldSarge

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    I'm gonna have to try that. Gotta make one to take with me to Asscrackistan. Too cool. I'll let you know how it works at high altitude LOL!

    have you had any problem with the screen support bending or warping with the heat? Just wondering. any prefference on what fuel works the best?

    Awsome stuff man! Never would have thought of that. Do more with less. Good job!
     
  25. hanzo

    hanzo Scout

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    I made one of those last week to take on my weekend camping trip. I tested it at home but didn't use it at camp as we did most everything on the camp fire.

    Mine was made out of an empty almond can after my wife polished it off and a soup can after I finished that one.

    Mine isn't as nice looking as yours. It is a bit rough since I wanted to make it with a SAK. I used the farmer model. I wanted to prove to myself that I could make one with what was in my pockets. Afterward, I drilled out the holes to make it a little neater, but the holes are still small on mine to keep it true to size.

    But the bottom line is it works. It wasn't hard to make even using the awl to make holes.
     
  26. hanzo

    hanzo Scout

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    Here's mine.

    [​IMG]

    Sorry about the bad picture. It was last week taken on the side of my house. The stove was just lit.

    Is there a technique to putting the wood in? I just shoved it in any which way.

    After about 10 to 15 minutes in the wind, I still saw quite a bit of unburned wood. But I had to go in to get my kids fed so I put the stove in my grill to smother it. When I checked it the next morning to pack it for camp, the wood burned to ash.
     
  27. FGYT

    FGYT Scout

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    nice job
    i played making some a while ago but thats a much neater more Professional build

    ATB

    Duncan
     
  28. slammer187

    slammer187 Tracker

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    sash Scout

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    Thank you so much! I was having a time trying to wrap my little mind around the process involved, but the pretty picture made the whole thing make sense for me. :)
     
  30. campcrafter

    campcrafter Scout

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    All nicely done

    great pics

    cc
     
  31. Ursinos

    Ursinos Guide

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    yeah, I was having much the same issue, and like I said before, I have this thing where I like to understand the way things work.

    "the profoundest act of worship is to try to understand" is a quote that's a big part of my life :D

    I'm not sure why I didn't start with wikipedia to begin with lol.
     
  32. pedro

    pedro Scout

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    I don't mean to step on anyone's toes, but that is not how these stoves work. That diagram is for a downdraft gasifier. These are updraft gasifiers, specifically Top Lit Updraft Gasifiers (T-LUDs). The fire burns from the top down, leaving charcoal in it's wake. This is done in an oxygen depleted burn. That's a fancy way of saying that you don't feed much air at all to the primary fire. All of the air is travelling up, both inside the firebox and outside. The primary fire generates wood gas (smoke). As the smoke travels up thruogh the pile of charcoal, the charcoal filters out impurities much like an activated charcoal water filter. The outer jacket acts as a chimney, creating a draft that forces air into the top air inlets (secondary burn). This air mixes with the now purified wood gas and burns much cleaner. That is the theory. If you google T-LUD you will get lots more info.
    One of the reasons why there is so much disinformation out there about these things is that the paper that documents much of the original research refers to them as INVERTED downdraft gasifiers. If , like me, you didn't know anything about the history of downdraft gasifiers when first approaching the subject, this can be very confusing. I hope that this clears a few things up.

    That being said, nice job on your stove!
     
    Last edited: Dec 15, 2009
  33. Ursinos

    Ursinos Guide

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    I was just going by the only thing I could find at the time on woodgas stoves. Thats what i found. I don't claim to be an expert, in fact, I was clueless and just shared what I found on it.
     
  34. pedro

    pedro Scout

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    Hey, that's okay. I'm trying not to be too overbearing. There has been a ton of misunderstanding on many different forums concerning wood gasification. I just want to help others understand.
     
  35. Sgt. Mac

    Sgt. Mac Elder

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    Great job on that
     
  36. GrouchyBear

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    I can't wait to finish work this week and try this on my workbench. Only question I have is: why do you have to cut the bottom out of the qt. can? You've already got precise vents in it. That open bottom if you sit it on level ground vs. unlevel ground the air feed would be pretty inconsistent wouldn't it?

    There's probably an easy answer that's why I'm asking.
     
  37. Homeslice

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    The inner can must be inserted from the bottom.

    I have a question about what kind of grill was used for the inner 'shelf' and how it was made to stay in place. Any info?
     
  38. Trekon86

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    Looks like galvanized hardware cloth:)
    PMZ
     
  39. hanzo

    hanzo Scout

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    You don't. I left the bottom intact on mine. I shoved the inner can in from the top. That's why you will see little score lines to allow for the fit. I didn't use a quart paint can for the outer can though. Mine was a Costco can of almonds.

    I did keep the plastic cover for the outer can though. That way, it I store an alcohol stove in the gas stove, it will keep everything inside.
     
  40. GrouchyBear

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    Effective approach with the plastic lid.
     
  41. Valcas1

    Valcas1 Scout

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    This particular variation of a wood gas stove uses the paint can and a Progresso soup can. if you cut the bottom and insert the can from the bottom you will get a clean fit. I am not saying you have to do it this way It just give you a very easy, clean fit and finish. I think the bigger question is why not cut the bottom out? if there is uneven ground the fact that there is not a flat bottom would make it easier to st up your stove. I have not messed around with burning on uneven ground so I will have to try it out.

    Another added benefit to removing the bottom is you can store your pot stand between the walls of the stove.

    All good questions.
     
  42. Valcas1

    Valcas1 Scout

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    It is 1/2" hardware cloth simply bent to shape and inserted into the inner can, I will post clear pictures laeter. Some will dispute if this is even necessary, truth is, I don't know. Research that I did showed a benefit, so I just went with it.
     
  43. GrouchyBear

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    Ingenius little stove

    Another added benefit to removing the bottom is you can store your pot stand between the walls of the stove.

    All good questions.[/QUOTE]
    --------------------------------
    The qt can has two air sources: the precise holes you have drilled on the circumference and the uncontrolled airflow through the open bottom where a lid used to be. If the qt can was placed on a perfectly flat surface there would be no air intake.

    The holes in the bottom of the qt can: are they actually a backup and/or a supplemental air source ?

    The original post talked about experimenting with those qt can holes.That's a clue. This stove is nowhere as simple as it looks! It's ingenious.
     
  44. Homeslice

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    I am so confused. Off to the hardware store I go. We will see if I can actually build one of these things.
     
  45. Valcas1

    Valcas1 Scout

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    --------------------------------
    [/QUOTE]
    I can not tell you what would happen if the stove had a closed bottom. the only thing that I can offer you is my results burning the stove on a solid surface of concrete and a fairly level surface of a grass. The stove is designed, not by me to only use the 4 holes around the base. I can't imagine that when it is placed on a level concrete surface it is gaining much draft from the open bottom. Again only my opinion and real life experience with this stove. The way the stove is designed it can not be done with these materials with a closed bottom. I agree that the stove is a design marvel. I saw the potential and just copied what I saw. I was not trying to re invent the whell, so to speak.

    If I can offer anyone more insight, please just ask.

    Paul
     
  46. hanzo

    hanzo Scout

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    I can not tell you what would happen if the stove had a closed bottom. the only thing that I can offer you is my results burning the stove on a solid surface of concrete and a fairly level surface of a grass. The stove is designed, not by me to only use the 4 holes around the base. I can't imagine that when it is placed on a level concrete surface it is gaining much draft from the open bottom. Again only my opinion and real life experience with this stove. The way the stove is designed it can not be done with these materials with a closed bottom. I agree that the stove is a design marvel. I saw the potential and just copied what I saw. I was not trying to re invent the whell, so to speak.

    If I can offer anyone more insight, please just ask.

    Paul[/QUOTE]


    The stove works just fine with a closed bottom. To insert from the top, you need to score the top so the inner can can slide in.

    I agree that leaving the bottom open would allow more storage options. But I was ok just storing stuff from the top.
     
  47. Spork

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    I started on mine. I'm going to try using that paint roller screen for the fire grate and the hash can for the pot stand.
     
  48. Homeslice

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    Finished my stove with the exception of the screen and pot stand. Tried it out last night and it works well. I didn't have a stepwise bit and didn't want to buy one for $20, so a few of my holes are raggedy and it's not as pretty as yours, but it works, and I built it! I'll try to clean it up a little with the Dremel tool before I post any pictures.
     
  49. Valcas1

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    Nice going Spork, Does that hash can fit up on top of the paint can? Please post pictures of the finished stove and any improvements or observations.

    Paul
     
  50. Spork

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    Just finished it.

    The hash can will sit on top of the paint can and be stable, but it is a little larger in diameter than the groove for the lid and it will shift around a little.

    I drilled the bottom of the hash can with 8 half inch holes spaced evenly close to the rim. With a pair of electrician's scissors, I cut the bottom out so that it left enough material to bend some tabs to fit into the lid groove. It is a little ugly, but it works.

    This keeps the hash can from shifting and if you tweak the tabs a little it sort of snaps onto the paint can.

    The hash can will store inside the paint can.
     

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