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Outdoor Section => Backwoods Cuisine => Topic started by: Lynn LeFey on September 29, 2015, 12:00:03 AM

Title: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Lynn LeFey on September 29, 2015, 12:00:03 AM
Some time back, I made a mess of wood gas stoves. They have some amazing benefits, and a few unfortunate drawbacks. Overall, though, they're awesome. I thought it'd be cool to develop a method to make them with 'field expedient' tools. What follows is a VERY 'down and dirty' method, but produces a perfectly functional stove in short order.

I used a Leatherman Rebar. But all it needs is the pliers, awl, and can opener. While many tools would work for this, I'm sorry to say Leatherman is going to have Victorinox MTs beat in this build, due to the nature of their awls and can openers. The awl edge on the Leatherman handles the abuse it's about to take better, and the can opener's hawk beak style works better in this build. That said, I'm certain a Vic could do it as well. It just might take more of a beating doing it.

1: Can selection. I prefer a standard #300 can for the inner chamber. I don't know what the outer can is called, but is 4" (10cm) in diameter, and just a bit taller than a standard can. You will need two of the larger size cans. One is for the outer chamber, and one is for the pot stand. For the larger cans, you will want at least one of them (the one that will become the outside of the stove) to have sealing seams on both ends of the can. For the other two cans, it doesn't matter either way.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0410_zpsfbo5vwkc.jpg)

I guess the official first step is 'remove tops from all cans'. I would probably add 'eat contents', but you can store the contents of the cans in the fridge, feed them to rabid weasels, or whatever you want to do. Not my business. You're probably going to want to wash the inside of the cans as well, unless you like the smell of burning corned beef, or ravioli, or tamales, or whatever. Again... not really my business.

2: This next step is just good work practice. PUT ON WORK GLOVES. Otherwise, you're going to bleed. If you're Captain Spaulding, or NNR, you might also want paramedics standing by. You will notice in the pics, I'm not wearing work gloves, because I like to live dangerously. And yes, by the end of the project, I was bleeding. I got one tiny poke in my left thumb.

3: Start with the smaller can. About an inch from the rim of the open end, punch a hole in the can with the awl. I found placing the awl on the can and giving a forceful strike with the heel of the hand would punch through the material. The hole doesn't need to drive the awl all of the way into the material. just break through.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0411_zpszddhbzy6.jpg)

4: From there, you can push the awl in by hand. Then rotate the awl counter-clockwise, to ream the hole out. Rotating the awl clockwise frequently causes sharp jags of metal to form around the outside of the hole, and then you'll have to deal with them later.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0412_zpsjrcx40hr.jpg)

5: Repeat 3, and 4, but directly across the can from the hole you just made.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0413_zpsobntqwgo.jpg)

6: Now, half way between those holes, make two more (so you have 4 holes evenly spaced). Then split the difference again between the holes, making 4 more, so that you end up with 8 holes around the can, more-or-less evenly spaced.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0414_zpslzvony1x.jpg)

7: Repeat the process, and make 8 holes on the bottom, again, about an inch from the end of the can.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0415_zps6v27hp3o.jpg)

8: And finally, for the inside can, make 8 more holes, closer toward the bottom of the can, offset from the first 8 you make. Your can will now have 8 holes near the open end, and 16 near the unopen end. And that completes the inner can.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0416_zps0e927czk.jpg)

9: Turn one of the larger cans bottom up. Make sure this is one of the cans with seal rims on both ends. Center the small can on top of the larger can, and, using the awl, scribe a mark to show its circumference. Since my can had rings impressed into the end, I just scratched little marks to show where it sat on that ring. My scratch barely shows up in the photo. It's just to the left of the smaller can.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0417_zpscmvn7gdv.jpg)

10: You're going to cut out a hole in the lid of the larger can that's a bit smaller than the diameter of the smaller can. Start by punching a small hole with the awl, using the same technique described in step 3.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0418_zpsvboofitq.jpg)

11: Using the can opener, cut the circular hole out of the lid. You might find it difficult to complete the last half inch (or centimeter). That's alright. We'll deal with that in the next step. Without the aid of the leverage of hooking the can opener on the rim of the can, this becomes a completely brute force operation. If you hate your plain edge blade, you can use it instead, by placing it tip-on against the can, and using the same forceful strike with heel of the palm to drive the point into the metal as I described with the awl. It will take about 40 strikes, and i assume that's not good for your blade, so I HIGHLY recommend you just gut it out with the can opener.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0419_zpsqxvtgsxn.jpg)

12: For the last half inch or so of that cut, just bend the piece back and forthe along the remaining bit until the metal snaps. Be careful here. There are a lot of jagged edges at this point.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0421_zpsf0u45ery.jpg)

13: Going back to the awl, punch a hole about 1/3" (1 cm) from the newly cut opening.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0422_zps7kmeie7j.jpg)

14: As you did with the holes around the inner can, repeat this directly across the hole on the other side. Then at cross quarters. Then do it again to divide the circumference into 8ths, and 16ths. Take care to point the sharp edge of the awl toward the circular hole you cut in the center of the lid.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0423_zpsttpdez0y.jpg)

15: With spacing figured out, now go back with the sharp edge of the awl pointed toward the center hole, and drive the awl in all the way. The goal here is to split the metal into the circular hole. You may find that you have to lever the Rebar's handle away from the can to complete the split. What you should end up with are 16 tabs of metal, forming a circle.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0424_zpsjr1l12rz.jpg)

16: This step may or may not be needed. You may find that you have to bend these tabs in slightly. I used the butt end of the Rebar to force the tabs down slightly. DO NOT bend these in too far. If your inner can just drops right through the hole in a later step, you've gone too far (which is exactly what happened with me on this build). But fear not. The tabs can be bent back just as easily.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0425_zpsej5huz3r.jpg)

17: Now we are going to begin working on the other end of the outer can. So, on the end with the lid completely cut off, use your can opener to create two V cuts on the can. If you can get the two Vs to join near the can rim, all the better.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0426_zpsgivt1wqf.jpg)

18: Repeat this directly across the can. Then do it again at quarters. From there, there isn't sufficient room to split the quarters into eights, but you can put single v cuts in between the quarters.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0427_zpskwryhchm.jpg)

19: Well... now you're left with something that looks like the mouth of a smurfing lamprey. You have two options. You can either break each of the triangles of material out by bending it back and forth until it snaps, OR you can take those ones pointing away from the outside, fold the pointy end over half way, then over again to sit flush with the rim.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0428_zpsspedgyd3.jpg)

20: You will be left with 4 bits to deal with. If you connected your V cuts in step 17, they will be detached triangles, pointing toward the can opening. If you didn't quite connect them, used the needle nose pliers the just break the connection. Then, for all pieces, fold the triangular piece over inward, and crush it flat against the inside of the can wall with the pliers. TAKE CARE when doing this, not to catch the rim of the can in the wire cutters.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0434_zpsnbk2tzgb.jpg)

21: Take the smaller can, and put the end with the solid bottom flush against the side of the larger can with the tabs cut in it. Press the smaller can into the opening with the tabs. This may require a bit of force, and may also require some fiddling with the cuts along the tabs. The end result should be a very tight friction fit. If your smaller can drops right through like mine did on this build, then bend your tabs flat again, and start over with pressing it in.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0435_zpskrz6cm47.jpg)

22. I'm going to gloss over this step a bit. Make the pot stand by the same process described in 17 to 20. However, leave out one of the single V cuts. This should be done on the second large can, on the open end. When you've cut the vent holes, then use the awl to make a hole about 2 inches (5 cm) from the rim, then use the can opener as described in step 11 to 'brute force' cut around the circumference of the can. Then use the pliers to roll the edge cut by the can opener. Finally, cut a slit (in the area left by the missing V cut) in the can's rim with the wire cutters. Then cut a notch at the same location along the rolled edge you created from the can opener cut. There will now be about 2 inches of can material between the two notches you need to break, probably by repeated small folds, but possibly by tearing with the pliers. Your goal is to turn the 2" tall circle of can you have into a C . It's going to make an ugly edge either way. Once accomplished, fold the edges of both ends of the C over with pliers. The opening I described here is seen in the upper right of the photo.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0436_zpsoheg3w5k.jpg)

And... You're done.

Wt. 5.5 oz (156g). Cost:$0. Cost of full cans of food: $6 (but that was about 5 meals).

I'll describe the first burn test in the next post.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Lynn LeFey on September 29, 2015, 12:27:07 AM
So, Immediately upon finishing this, I took it onto the deck to test it.

These things take about 3 or 4 minutes to get up to full function. When they do, they stop smoking. At that point, put on the pot holder, and set your container on it.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0439_zpsacsxh2b8.jpg)

It took 8 minutes to bring water to a boil. This was without lid or windscreen. Previous times tested with very similar stoves were 5:30 for a boil with a lid on.

Once the 2 cups of water was at a boil, I removed the container and timed the remainder of the burn. It continued for another 10 minutes.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0440_zpsbk2umxob.jpg)

When the wood gasification is complete, it will start smoking. At this point, I recommend dousing the coals. That takes about a quarter to half cup of water. It makes very little smoke or ash to do this.

Once the coals are out, the stove will be cool enough to handle in about 3 minutes.

What's left is really good charcoal. Some folks in the survivalist communities know a number of good uses for good charcoal, and I highly recommend these stoves as a great way to produce small quantities of it.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0442_zpsguwxreld.jpg)

Inevitably, I feel a need to compare this to the backpacker stove I made here...
http://forum.multitool.org/index.php/topic,62174.0.html

Well... minus the ability to pack it flat, and a bit of easier ignition, the backpack stove had no advantages. The wood gas stove uses less wood to function. It boils water just as fast. It does it without creating a ton of soot, and makes virtually no smoke once up to temp. It actually weighs less (although it's more bulky). And as just demonstrated, it can be made with a single multitool, instead of requiring tin snips and a dremel. Also, since you're not disassembling it like a flat fold pack stove, you don't have to touch the bits coated in what little soot it does make, which means this thing is a lot less messy. Also, once it's going, there is no need to fuss with the fuel. It just goes until it's done.

Fuel and Cook Time: This thing took about 5 2-foot branches with a diameter about like a pencil to achieve its burn. I know for certain that it burns longer with hardwood, even little branches like this. With those, it might burn more like 25 minutes. And if you use wood pellets, it will burn about 45 minutes. As it was, using random yard debris, I got enough cook time to do two 2-cup boils.

Notes on construction: When I first learned of the wood gasification stove, I thought it was an awesome idea. However, the construction methodology was a bit 'precise' for my taste. Then I found a video on YouTube showing a 16 year old kid making one. His was much less technical, but they were always stressing that this hole had to be exactly such and such diameter, and the there couldn't be ANY gap in the press fit between inner and outer chamber, and on and on. All that's bullsmurf. I've made about 15 of these things now. They are REMARKABLY forgiving. You need lots of airflow going in from the bottom of the outer can, you need good airflow into the bottom of the small inner can. You need reasonable airflow into the top of the small can's hot air intake, and you need a meh seal between the two cans... as perfectly illustrated in my build above (Step 21 pic). You can see HUGE honking holes between the tabs and the inner can. Didn't seem to affect function one bit.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: sawman on September 29, 2015, 12:57:59 AM
I love my Rebar. Impressive what you've done with yours :tu:
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Lynn LeFey on September 29, 2015, 01:38:40 AM
The more I use it, the more I like it.

I kind of think of it as the baseline tool for 'Bug Out Bags', or general preparedness. I think the Wave is better, but for the difference in cost, function, and weight, the Rebar might be better dollar-for-dollar.

For this application, as i mentioned in the first post, both the awl and can opener of the Rebar are better suited to the task than a Victorinox equivalent. The Vic's awl is more useful as a wood drill, for instance, but the same thing that makes it better for that, the scoop groove in the awl, makes it worse for plunging into a tin can, since that fine thin edge can get beat up (and i HAVE beat of a Vic Awl trying this stunt). And the V cuts I use above are nigh impossible to do with the Vic can opener. It mangles the rim of the can when you try. Again, I know this from experience.

This isn't the first time I've tried to come up with a way to make one of these stoves with one tool. It's just the first time I've succeeded to a degree I felt was worth sharing.

I mentioned above in Step 11 that you can use your plain edge blade to make cuts. I say that from experience. It never damaged my edge, but every time I've done it, I fear it would. It feels straight up abusive to the tool, whether or not it can take it.

Also, not recommended by Leatherman, the Rebar makes a fair light hammer. :D

So, I went out and tested some of these cutting techniques with other MTs. Leatherman PST 2 and Wingman could both accomplish this, although the Wingman was SUPREMELY uncomfortable doing the brute force can opener stuff. While lacking an Awl, I felt secure using the Wingman's blade tip to punch holes.

I also tried the Gerber Bear Grylls 'Strata', and it's can opener worked like a frickin charm for the brute force can opener cutting. Also lacked an Awl, but also has a solid knife point I didn't feel afraid to use for punctures.

I also managed the work with two PST clones I have, to various degrees of success.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: sawman on September 29, 2015, 01:50:08 AM
Oh and BTW Lynn it's great to see you lurking about :cheers:
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: WWW on September 29, 2015, 02:09:44 AM
I'll have to read it all with a bit more calm later I just read the whole thing with a lot of calm, but I think it is a great idea. As I mentioned before, we should do a build with a MT only kind of thing.

Great to hear from you, and thanks for sharing your experience. I hope your injure wasn't that bad.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Lynn LeFey on September 29, 2015, 02:27:52 AM
I had, literally, one drop of blood that I squeezed out of the cut. I think I'll survive.  :rofl:
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: comis on September 29, 2015, 06:56:27 AM
Lynn,

Thank you for the great writeup and a good read, what's the volume of the pot that you boil water with?  I never build a woodstove like yours, and always kinda wonder whether the weight/fuel efficiency etc is worth making one.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Lynn LeFey on September 29, 2015, 08:09:54 AM
The pot I show in the picture is only 2 cups (473ml).

It's terrible, but I used it because a lot of 'just add hot water' backpacking food, like Mountain House brand, require 2 cups of water to make. I have some nicer pots, with larger volume that I could use, but just haven't tried them yet. I'm pretty sure this stove would boil a full liter on one burn.

EDIT: For the cost, and time required (maybe two hours), I think you would be pleased with making one. Worst case, you don't like it and are out a couple hours of work (or play, if you like messing around with multitools and cans).

EDIT part two: If you want to make one just to have the stove, not to play around with a multitool, I'd seriously recommend doing most of the cutting tasks with tin snips, if you have them. It'll save you a lot of effort.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: comis on September 29, 2015, 09:38:09 AM
Thanks Lynn for the info!  I guess I will keep this as a project that I could try during camping, where I live is a complete concrete jungle and I literally cannot find anything to use a fuel here. 

Most of time, I just use an alcohol stove or gas stove for boiling water for the dehydrated food, and virtually nothing to clean.  But it is good to know this stove doesn't create too much soot.  It gives me comfort to know that you've made it 15 times, and the measurement is not an exact science, so it is not impossible to make.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: styx on September 29, 2015, 06:09:46 PM
Nice work Lynn. Why not put this out as a pdf manual?

On the side note, would you care to discuss the can opener conundrum?  :P :drink:
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Lynn LeFey on September 29, 2015, 06:57:22 PM
Nice work Lynn. Why not put this out as a pdf manual?

Because I'm lazy. :D

No reason it couldn't be put out there, I guess. I just don't see a big 'market' for the idea outside of MT enthusiasts, and maybe a few bushcrafters and survivalists.


I will make no comment concerning can opener conundrums.  :bdh:   :D
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: styx on September 29, 2015, 08:08:33 PM
Well I know you loved that huge debate about can openers.

I think the survivalist community would love this
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Lynn LeFey on September 30, 2015, 12:28:54 AM
I thought I'd describe using this thing.

Another tutorial..

Gather some sticks. You want pieces no larger than 3/4" (19mm) in diameter. I find pieces that are more like the size of pencils are better. You will also want some that are even smaller. Of course, you want pieces that are dry, and not rotten. Hard wood will give you longer burn time, but these stoves will use anything.

Here's what I gathered, and it was more than enough...

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0443_zpszdjgktns.jpg)

Measure the inner chamber, up to the upper air holes. That's how long the pieces of wood should be. Break up your wood into that length, and put the pieces vertically into the burn chamber. The chamber should be reasonably full, but not packed. It should still rattle freely. If you have too much in the burn chamber, air won't get in, and it keep going out when you try to ignite it.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0444_zpsq7vzd5cw.jpg)

I have had the best luck with putting largest diameter sticks around the outside, and smaller diameter ones in the middle. This SEEMS to give it the best chance for ignition, although more on that later.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0445_zps4ylb6w98.jpg)

Here I've ignited the stove, and I'm waiting for it to get up to temperature. To the left is a Texport camping pot with 1 liter of water in it.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0446_zpsq9n8qoxo.jpg)

It was high humidity today (77%) and had rained this morning, so getting it started was a smurfing smurf! I've tried a number of starting methods in the past, and what seems to work best is to create a roll of about 4" (100mm) of duck tape into a loose roll, lighting it with a lighter, then stuffing it in between the small twigs (make sure to leave a bit of room for it in the burn chamber if this is your plan). I've also tried alcohol soaked cotton balls, vasoline soaked cotton balls, parafin soaked cotton balls, dryer lint, dryer lint soaked in parafin, etc. So far, the duck tape seems to work best.

This thing will smoke like any other wood fire while it's getting going, but once it's actually burning only the wood gas, it will get VERY clean. You may even have problems seeing the flames. However, I usually start cooking with it when the flames look about like the second picture in the second post of this thread.

The stove's pot holder easily held the pot and I got a 17 minute burn time. I had a lid on the pot. Unfortunately, while bubbles formed, it didn't have enough time to come to full boil.

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0447_zpso44siez8.jpg)

The harder the wood you use, the longer this thing will burn. With oak twigs, I have managed something like 27 minutes with the same size burn chamber. With wood pellets, I think I got 45 minutes once.

Toward the end of the burn, the fire may go out. It will then start smoking. Sometimes if you take your pot off, and blow into the top, you can get the coals hot enough again to reignite the wood gas. This can give you another 3 minutes or so of burn time. However, there will come a point where there's not much you can do, and it's pretty well dead. I have never been able to get the thing restarted by loading more wood into it, although I suppose it's possible. I just get a lot of smoke. At this point in the burn, I just douse the coals. You'll get a little ash fly out when you do. Once the coals are doused, this thing will get cool enough to touch in just a few minutes, and be ready to pack away.

So, there's all the wisdom I've accumulated about this contraption and it's operation. I find them finicky to get going, and awesome once they ARE going. I'm happy to hear if anyone comes up with a better method of ignition. I think it's just a part of top-down burns. They can be unfriendly. :shrug:
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: styx on September 30, 2015, 06:30:30 AM
I'd suggest giving jute twine and ranger bands a try. Jute soaked in wax was my dirty secret for a number of years.
Might also be worth while to split up the twigs, although that is just a shot in the dark
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Lynn LeFey on September 30, 2015, 04:26:27 PM
Jute twine with wax on it is what I started this last burn with. You can actually see the jute twine and tea candle in the pics above. After that failed (due mostly I think to too much wood in the burn chamber), I then used duck tape.

I just picked up an old bicycle tire this past weekend to make ranger bands with. I'll do a burn time test on one today.

The split twig notion is why I pack the center with the smallest twigs. The thinking being that they'll catch more readily than the thicker outer pieces.

Thanks for the feedback.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: styx on September 30, 2015, 05:35:11 PM
What about magnesium, potassium or guitar picks?
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Lynn LeFey on September 30, 2015, 10:20:53 PM
I gave my magnesium block away to a friend's son, don't have potassium, and never played the guitar. :D
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: WWW on September 30, 2015, 11:04:48 PM
What about magnesium, potassium or guitar picks?

Noooo! You got it all wrong, the Hendrix guy used guitars not guitar picks!!
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: styx on October 01, 2015, 06:29:02 AM
The picks can be scraped and catch sparks very well.

Magnesium is also in pencil sharpeners, so maybe you have it
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: shibafu on October 01, 2015, 12:33:13 PM
Thanks for posting this Lynn.  It's really interesting to see that they can be quite roughly made and still work well.  I must try this soon.  I still have a can of potatoes in the cupboard that I bought about 2 years ago, intending to turn the can into one of these, but never got around to it.

For getting the fire going I think a quarter of a hexamine block would work well.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Lynn LeFey on October 01, 2015, 04:15:33 PM
Yeah, that would work, but I'd rather use something less expensive/more readily available.

Please do give making one of these a shot, and see what you think. I'd like to get some feedback, and if a number of us all gave this a go, maybe we ,collectively, could improve the technique. I'm SURE there's room for improvement.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Lynn LeFey on October 06, 2015, 03:02:29 AM
I did another burn on this stove, using wood pellets. I thought maybe I'd misremembered or exaggerated the burn time in my head, so wanted to test it.

I got 49 minutes this time.

I used the same pot as above, again with 2 cups of water, and got good rolling boil in 19 minutes. Assuming the same temperature of fire all the way through burn time (which probably isn't the case), then i could have gotten another 2 cups of water up to boil by the end.

It's currently 66F (19C), moderate humidity, and a very light breeze.

I guess I will keep this as a project that I could try during camping, where I live is a complete concrete jungle and I literally cannot find anything to use a fuel here. 

See, I KNOW that's a lie, because I know your place is littered with little cut pieces of wood from all your saw testing.  :D
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: comis on October 06, 2015, 03:40:09 PM
I guess I will keep this as a project that I could try during camping, where I live is a complete concrete jungle and I literally cannot find anything to use a fuel here. 

See, I KNOW that's a lie, because I know your place is littered with little cut pieces of wood from all your saw testing.  :D

Ah...you got me there, sis!  Guilty as charged! :D

http://forum.multitool.org/index.php/topic,62327.0.html

I got nearly 200 pieces from doing the saw tests...and I think I have some idea what I gonna do next with these pieces.  >:D
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: rebel on October 06, 2015, 03:54:33 PM
Really interesting post and very nice work.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: WWW on October 11, 2015, 05:09:28 PM
 I wonder how well it will work with different dimensions? Although I'm not too far off, I don't have any #300 cans. We'll see how it goes.

 I'm half way done with the internal part ready, not having a Rebar I had to make do with the P4 and the Wave. It really messed up the awl and the can opener. How well did yours held up.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Lynn LeFey on October 11, 2015, 05:38:44 PM
The Rebar Awl took a very minor bit of damage from reaming the holes. The can opener was unaffected.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Lynn LeFey on October 12, 2015, 02:27:52 AM
I did another burn today of the stove.

I posted some pics in my 31-day off brand challenge thread about prepping some stuff...
http://forum.multitool.org/index.php/topic,62289.msg1163935.html#msg1163935

I ignited it with a piece of bicycle inner tube. Trying new things out.

So, it appears that the tree in my back yard is Ash. I took some of the deadfall that's been lying in our yard for about a year, that's good and dry, and processed it down into small pencil and matchstick size bits. Very little bark, and it should all have been good, dry hardwood. I was curious, if I didn't include green sticks, how it'd affect burn time.

So... uhh... Ignition went VERY well. I'd say that was the main benefit of using seasoned wood.

Burn time was only 17 minutes. Which I thought was weird. I would have expected it to burn longer.

Temp was about 70F (21C), moderate breeze. Maybe the breeze contributed to the fuel being consumed faster. I don't know.

I got a shot of it while it was burning very clean. In daylight, there are moments where you almost can't see flames from these things. At night, the blue flames are more clearly visible.

And for the science of why the orange flames almost disappear with these...
https://answers.yahoo.com/question/index?qid=20070610105922AAosEw7

(http://i105.photobucket.com/albums/m208/lynnlefey/IMG_0483_zpsnrzar6vu.jpg)
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: WWW on October 26, 2015, 07:32:38 PM
 Finally got around to finish it! Done a preliminary burn with a lot of shavings I had and small bits of wood. It burnt really fast but I think it was burning gas towards the end.

 All I have (in terms of big pieces) is lumber and not knowing how they were treated I would rather not use it, as soon as I get some fire wood I give it a proper testing.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Lynn LeFey on October 26, 2015, 07:37:03 PM
It sure LOOKS like it was working.

When the flame looks like it's coming out of the air holes at the top of the inner can, then it's burning the wood gas, and that looks like what's going on in the pic.

Very cool. :tu:

How did the construction go for you, and do you have any suggestions for change?
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: WWW on October 27, 2015, 10:43:39 PM
It sure LOOKS like it was working.

When the flame looks like it's coming out of the air holes at the top of the inner can, then it's burning the wood gas, and that looks like what's going on in the pic.

Very cool. :tu:

How did the construction go for you, and do you have any suggestions for change?

Aaaaaahhhh, I see!!! I'm glad it worked!!!

I managed to fail the triangles at the bottom. I could not connect the doubles but other than that it was pretty easy.

As far as the hole on the top (actually bottom of the can, top of the stove). I tried to punch the holes with the can opener, but I gave up very quickly. I used the knife seen in the first pic and at the end finished with the can opener. No visible damage to the tip or edge so I'm sure it would not be a problem to Wave's blade.

I was able to get a pretty tight fit, it was not what I was aiming for but it was what I got at the end.


Super fun project, very easy, and very cheap. I highly recommend and thank you Lynn for posting it here.  :tu:
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Lynn LeFey on October 27, 2015, 10:57:11 PM
I managed to fail the triangles at the bottom. I could not connect the doubles but other than that it was pretty easy.

This really isn't a problem at all. The only thing that matters is that 1) enough air can get in at the bottom of the outside can and 2) MAYBE, not sure, that it's more or less equal amounts all around. And like I said, I'm not even sure that's important, and 3) that there's enough of the can intact to maintain structure.

Aside from that, its aesthetics. And this project, for me, has never been about being all that high on the aesthetics scale. :D

In the end, the ONLY thing that matters is that it works.

It's also cool to hear that you got a good seal between inner and outer cans. That step has been one that's never been consistent for me. Sometimes I do, sometimes I don't.  Although, like other aspects, it ultimately seems to be more about aesthetics than function, since mine had a TERRIBLE seal and still worked fine.

 :shrug:

So, yeah, it just seems to be a pretty forgiving design.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: styx on October 28, 2015, 06:23:23 AM
Lynn would you mind if I took your text and pics to put it in a pdf? It should go without question but just so we're all clear, you're the signed author.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Lynn LeFey on October 28, 2015, 05:51:41 PM
While I'm not against the idea, would you mind waiting for the design to 'mature' a bit? I mean to say, wait for feedback to improve the methodology?

I guess if you wanted to put one out, understanding that it'd be like a "1.0" design, i guess you could.
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: styx on October 28, 2015, 07:17:19 PM
Sure, I'll wait. After all you're the boss lady with this
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Don Pablo on July 28, 2017, 07:28:40 PM
I'm thinking about making one of these, they sound awesome.
Aquiring the rght can sizes might be harder on this side of the pond.  :think:
Too bad that the pics are gone.  :(
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: WWW on August 01, 2017, 02:47:40 AM
I'm thinking about making one of these, they sound awesome.
Aquiring the rght can sizes might be harder on this side of the pond.  :think:
Too bad that the pics are gone.  :(

  I'm glad I gave up the photobucket thing, is so terrible!!! But do try it, as previously said, it is a super fun project, requires little tools (can be done with a multi), and is dirt cheap. As far as can size go, you don't need the sizes used, you just need a one that is smaller than the other (I think).
Title: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: 4everYoung on August 01, 2017, 02:51:15 AM
I'm thinking about making one of these, they sound awesome.
Aquiring the rght can sizes might be harder on this side of the pond.  :think:
Too bad that the pics are gone.  :(
These are actually very simple to make.
I mad a wood gasifier/rocket stove hybrid just last week. I used for cans to make mine tho. YouTube has plenty of instructional videos in both of them.
(https://uploads.tapatalk-cdn.com/20170801/649e3f4d1df15ab8bf75d49f2c060950.jpg)
Title: Re: Wood gas stoves with three cans and a Rebar (Pic Heavy)
Post by: Don Pablo on August 01, 2017, 10:44:17 AM
Thanks. I'll keep an eye out for suitable cans. :)