Originally built the Mark's Pennywood wood stove and was pleased with it's performance. However the more I read about the secondary combustion concept the more I became interested in the BushBuddy design. So I decided to see if I could build one out of available materials and keep it light and simple.

I cut off the beer can just below the top rim to allow the soup can to dorp inside but catch and rest on top of the beer can's top edge/lip. Next was drilling lots of holes!

Hmm, somehow the captions got wacked from above? I guess the pics tell the story. Boiled 16oz of water in ~10min with a hand full of twigs, bark and pine needles. Continued to simmer over the coals for another 10-15minutes. Sorry my scale needs a fresh battery or I'd post the weight ...but it's light! I'll add this ASAP. Back to the lab for now.

Cheers, Steve

Nice work, Steve. How tight is the fit between the soup and Fosters can?

Thanks, It's less than a 1/4"? I thought it was more but the beer can is 3.25" and the soup can is 2.8"! Just enough to keep the aluminum from melting and still allow a draft effect. Tonight I'll get some flame shots to confirm the secondary combustion.

Man, I'm impressed. Gotta make one!

Thanks,
Todd

SO COOL Steve! I'm totally on this one- a DIY project that I can handle for sure!

Can't wait to hear more!

Thanks-
Doug

How much does it all weigh in at, Steve? Please get fresh batteries! :-)>

Ok I robbed the battery from the bathroom scale for my postal scale to see what the Fosters BB weighed. Would you believe 2.2oz! Woohoo and with the riser/pot stand its 2.5oz. Can't wait to hit the trail with this guy!

AND I fired it up tonight to see if it's actually gasifying and doing a secondary combustion ...here's the proof. Note the flames streaming out of the top holes. That's gasified wood fumes!


Have fun! Any suggestions welcomed, Steve

Wow, all this and the price is right, too!
Jolly good show!

AND Fosters doesn't taste too bad. It's surely not my favorite beer but the result is worth it.

=D Steve

Steve, do you have the brand name & sizes for the different cans? I was smart enough to figure out the Fosters can...

I have to try one of these puppies as well...

I've been tossing around the idea of making a BB-type stove since Franco posted his. I guess I need to get a hold of another Fosters can so I can get to work on making one of these. Lord knows there's plenty of spare wood in the Ozarks...

Adam

The only can that's really important is the 24oz beer can. It should have straight sides unlike the Heineken can. The steel burner can that fits inside the beer can is a 15oz can. (approx. 2.8" dia) Mine just happens to be a Healthy Choice soup can. But I see lots of 15oz cans in the cupboard that would work! It's important to choose a can that has a rounded bottom and doesn't have a bead or lip on the bottom like the top where they join the top to the side of the can (see pic) Or it won't drop into the beer can. It's this lip that allows to burner to rest on the edge of the beer can.

The riser/pot stand can is an aluminum cat food can. Same size as a standard tuna can but larger than the one used for the cat stove. Sorry I don't have the specific brand. I need to go shopping and pickup some more to build a few of these stoves for friends soon.

The most time consuming part of building this stove is drilling all those darn holes in the burner. It helps to have a drill press. Maybe an alternative would be to cut the can's bottom out and drop in a screen?

Cutting the beer can is a little challenging. I've not come up with perfect cut method yet? If some one has a suggestion please chime in?



Hope this helps and let me know how it goes. Be careful and have fun! Steve

When I cut the top off of my Fosters can to use it as a pot I used one of the side-cutting can openers. It worked great and left a clean edge. I just stole my from my mom but I would almost bet you could find one at Wal-Mart or your grocery store.

One question; how long to you think the stove will last? I recall Franco saying that he felt comfortable using his for a certain number of burns before he thought it would need replacing. Do you think it would be a good idea to periodically go through and do a rebuild of the stove or does it seem to be holding up fairly well for you? From what I recall from burning trash as a child (I lived on a farm so no one came to get rid of our trash) the steel cans eventually got weak enough after many burnings that I could poke right through it with a piece of rebar.

Adam

Good Cook Safecut works well but is pricy. Albertson's and Safeway have them.

Another choice I know of is the Orbi Safe Cut. Haven't used this one.

Good Job Steve... curious, what did you use for punching holes, a whitney punch?

Something to consider. In my experiments with tincanium stoves, I've concluded that it is important to restrict your primary air (fewer/ smaller lower holes)--otherwise you produce more smoke than the oxygen coming through the secondary (higher) air holes can provide. I've examined my Bushbuddy, and concluded that Fritz has done his calculations very precisely, and that's what makes it such a smokeless stove.

The serious stovers (see their discussion ongoing @ http://www.repp.org/discussiongroups/resources/stoves/) suggest a 5:1 ratio. That is, have five times more air going through your _secondary_ (upper) holes than through your lower holes. I might suggest more like 3/1 for natural draft (fanless) stoves. Following this ratio, more or less, should result in the kind of "candle" flame put out by the Bushbuddy.

BTW, if, sans pot, you see the flames climbing very high, this is proof that there is not enough secondary air--flames climb in search of oxygen, so to speak.

Hapy stoving,

Muskrat the pyro

I'm wondering whether a ceramic engine paint might be of use on the can to increase the lifetime. Some are good to very high temperatures, and I don't think there would be any problem with toxicity, since the fumes wouldn't go into the pot.

Also, I've read a little on this, but I still don't quite "get" how they work... if you could, a little explanation of the airflow would be helpful, using your design as an example.

cool project...

Jaiden,

Here's a link for the Zen stoves web site, its probably the best stove resource on the net.

http://zenstoves.net/

Go to the "how stoves work" section, then the wood gas stove section for a detailed explaination with illustrations.

Edited by monospot on 06/06/2007 14:05:24 MDT.

More ideas on how to cut open the beer can would be appreciated. I have the opener that leaves a smooth top etc. and apparently you cut your can below the top of the rim because I don't seem to be able to fit the 15oz can inside the beer can with the rim intact as the super duper can openers leave them. (yes I went to many grocery stores in search of the super duper non can destroying can openers). I made one can to go with the esbit stove sold through this website and it works great, but the can I found in the cubard that matches the one you used will not fit inside with the rim still attached. Ideas?

Yes, I did read that page, but the stove in the pictures is very different. The zenstoves image shows all the airflow going upward, with extra air being added after the fuel and mixed in a high temperature zone which causes a strong updraft.

In this thread's stove, air can only enter the beer can on the bottom, and there doesn't seem to be any way to control how much air enters the inside can (top vs bottom)

I guess what I'm saying is I can't picture the airflow... maybe I'm just slow today.

>More ideas on how to cut open the beer can would be appreciated.


A classic method often used to make alcohol stoves from pop cans is to use a utility knife blade clamped into a book at the proper height. See "FIGURE 7" on this page. I use a C-clamp to hold the book steady, then I can use two hands to turn the can smoothly.

Edited by Otter on 06/06/2007 20:50:12 MDT.

Thanks Douglas. Very helpful.

I cut the can with a pair of scissors. This works well.

As far as taking the TOP off of the can this is a different matter. The SafeCut can openener (and similar ones I have tried) just eat up the can. The diameter of the pop can is too small, I think. They don't work with energy-drink cans either ("red bull", etc).

Also, in the classic open-top stove design the bottom is cut out of the can. See the web page referenced in a prior post... image 5 I think. This picture could be captioned "how to cut off your finger with a pop can and a sharp knife"... but it does work. Just be careful.

Edited by jjpitts on 06/07/2007 10:33:57 MDT.

Not my idea but this works better than putting the razorblade in a book as it is securely held.

Can is then CAREFULLY rolled on the blade that scores the can until the cut goes through.

This leaves a clean cut--if you do it slow and easy

Drilling the holes in the soup can is no problem as the can is stiff,however, the foster can is flimsey and my attempts to drill leave torn and destorted holes. PLEASE HELP.

Perhaps the use of a backer material---piece of PVC pipe of a diameter that would fit inside comes to mind, a reinforcing tape (?)---would make for cleaner drilling.

Kevin,
The backing is a good idea. PVC pipe,however, will not fit tight as the top of the can is steped and is smaller than the area where the holes go.
Thanks
Mike

As an alternative could you fill the can with water and freeze it?
Ron

Bingo! Where's my light bulb emoticon?

What a simply elegant idea! Once the top is gone, there should be no danger of distorting the can—excellent!
Thanks Ron.

Try a hand held hole punch, it even works on the relatively thick walls of cat food cans. On second thought... no.

Edited by Brett1234 on 06/07/2007 20:24:46 MDT.

The frozen water trick. Great idea. One could also use the largest diameter dowel they could get their hands on and after clamping it in a vice, slip the beer can over it (the dowel piece protruding from the vice would be slightly shorter than the can's height). The dowel should just about approximate the curvature of the can. You would have to rotate the dowel occasionally to keep fresh, undrilled wood stock under the can. I was thinking the ice might start turning to chips and water after a few drill holes.

How about sand? Would that work?

I just realized the dowel would hit the lip just as the PVC pipe would mentioned above by someone else. A way around that would be to find a dowel, small diameter wood pole, etc slightly smaller than the beer can opening and cut it a bit shorter than the can's height. Drill a hole lengthwise through the center, then press fit a rod or smaller diameter dowel into it. This would be clamped into the vice. Keep the jig for future beer can replacements. The outer dowel could also be replaced easily enough.

I read Steve's experiment with interest and thought I would try. 24 ounce aluminium beer cans do not exist in England.
I made a stove as much like Steve as I could based on a cut down 1 litre steel beer can (it was too tall). This can was the outer jacket and structure. The firebox was a Salmon can about the same size and shape as Steve's but which has a tapered shape wider at the top with a top rim that fits into a hole in the 1 litre can's top. The pot stand was a black treacle tin which was a telescopic fit in the open bottom of the 1 litre can when not in use but just nested between the outer and firebox rims when put to use. The stove weighed about 130 gram and had good secondary combustion, like in Steve's picture, when the firebox got hot enough. It was best fed little and often. However the cut bottom of the litre can was flimsy, the whole stove seemed too tall, unstable and hard to shield from the wind. And the bottom of the firebox got choked with ash.

Someone on the TGO site told me that it was possible to get an imported Japanese 2 litre Aluminium beer can 110mm diameter that he has used to make an ultralight 28 gram cooking pot.
I got one made a litre cook pot 35 gram from the bottom and used the top as the outer jacket of another stove. The outer jacket does not reach the ground. The firebox and ashpit is a 130mm high 100mm wide steel dog food tin with a smaller bottom rim ( this is important because the smaller rim fits neatly inside the outer jacket, so this can is used upside down) I used 2 titanium tent skewers through holes 30mm up the tin to rest a grate made from a bit of 15mm grid I cut from a cooling rack ( for cooling new loaves). The pot stand is a 1lb steel golden syrup tin. This again nests well inside the firebox ( through the open bottom) when not in use, but fits inside the smaller top rim on a little annular vestige of the firebox original bottom (remember its upside down).
I found a large Aluminium foil turkey bag which is large enough to make a complete ring windshield 300mm high. Folded in half this rolls round the firebox for storage. Everthing fits in the 1 litre pot except the outer jacket which I had to slit to get it to slide over the pot. final packed size 160mm x 111mm diameter, with room inside for tinder, pot grab etc.
When assembled the top of the pot stand is 210mm above ground.
The whole pot,stove,windshield, outer jacket,grate weighs 200 gram.
With dry wood and ideal conditions it boils 500ml of water in 5 minutes from ignition.
28 gram= 1 oz, 100mm= 4", 1 litre= about 34 English fluid ounces

I read Steve's experiment with interest and thought I would try. 24 ounce aluminium beer cans do not exist in England.
I made a stove as much like Steve as I could based on a cut down 1 litre steel beer can (it was too tall). This can was the outer jacket and structure. The firebox was a Salmon can about the same size and shape as Steve's but which has a tapered shape wider at the top with a top rim that fits into a hole in the 1 litre can's top. The pot stand was a black treacle tin which was a telescopic fit in the open bottom of the 1 litre can when not in use but just nested between the outer and firebox rims when put to use. The stove weighed about 130 gram and had good secondary combustion, like in Steve's picture, when the firebox got hot enough. It was best fed little and often. However the cut bottom of the litre can was flimsy, the whole stove seemed too tall, unstable and hard to shield from the wind. And the bottom of the firebox got choked with ash.

Someone on the TGO site told me that it was possible to get an imported Japanese 2 litre Aluminium beer can 110mm diameter that he has used to make an ultralight 28 gram cooking pot.
I got one made a litre cook pot 35 gram from the bottom and used the top as the outer jacket of another stove. The outer jacket does not reach the ground. The firebox and ashpit is a 130mm high 100mm wide steel dog food tin with a smaller bottom rim ( this is important because the smaller rim fits neatly inside the outer jacket, so this can is used upside down) I used 2 titanium tent skewers through holes 30mm up the tin to rest a grate made from a bit of 15mm grid I cut from a cooling rack ( for cooling new loaves). The pot stand is a 1lb steel golden syrup tin. This again nests well inside the firebox ( through the open bottom) when not in use, but fits inside the smaller top rim on a little annular vestige of the firebox original bottom (remember its upside down).
I found a large Aluminium foil turkey bag which is large enough to make a complete ring windshield 300mm high. Folded in half this rolls round the firebox for storage. Everthing fits in the 1 litre pot except the outer jacket which I had to slit to get it to slide over the pot. final packed size 160mm x 111mm diameter, with room inside for tinder, pot grab etc.
When assembled the top of the pot stand is 210mm above ground.
The whole pot,stove,windshield, outer jacket,grate weighs 200 gram.
With dry wood and ideal conditions it boils 500ml of water in 5 minutes from ignition.
28 gram= 1 oz, 100mm= 4", 1 litre= about 34 English fluid ounces

Derek, I'd be interested to hear how you find the UL 1 L cookpot? I've been looking for an UL pot that is larger than the Heineken can, but was told that larger beercans are not strong enough. Do you think the pot is robust enough for backpacking? Also, what brand/model of beercan did you use, and where did you obtain it?

Edited by chris_jackson on 07/19/2007 21:14:11 MDT.

("Note the flames streaming out of the top holes. That's gasified wood fumes!")

I think what you are seeing is oxygen coming into the stove through the upper holes, not gassified wood fumes.The flow of air is forming a pattern in the rising flames that gives the impression of flames comming from the holes. If gas was comming through the holes it would show a complete circle of flame surrounding the holes(like the flame comming out the jets of an alcohol stove). The gas comming off the burning wood is following the path of least resistance, the large center opening, not the cavity between the walls of the two cans. The gassification is occuring at the bottom of the stove where the wood is. Air is entering at the bottom enableing the wood to burn/gassify. If complete combustion is not attained at the bottom it will combust once it reaches the top where the gasses are mix with incoming air through the top holes.

In your photo you can see the hole on the right is not encircled in flame nor is the one to the rear(top of hole showing a little). Hole on the left has no flame around it at all.

Hi~Dan, You are absolutely right!
The main component of biomass gasification is carbon monoxide, its moving direction is upward, cannot sink and then comes out from the upper side hole.
Nearly all camping biomass gasification stove should be called hot air assistant combustion stove, I suggested use this kind of word.

Edited by asidesign on 07/24/2007 11:13:14 MDT.

It is fragile but useable. I believe it will survive actual use but might get damaged when packed away. I pack it tightly with other telescoped bits of my wood stove so it is stiffened. If you just packed the pot the top edge which has no rim would be vulnerable. If you had a use for the top of the can you might be able to pack both bits together like I do that would help.
Having no rim it is a problem lifting it off when boiling as a pot gripper does not work. I made one work by weaving a bit of bicycle spoke, in the right place to act as a rim for the gripper to grip.
I got the can imported from Japan from an English importer www.MountFugi.co.uk Asahi super dry 2L giant can. I believe there is a Japanese 3l aluminium beer can that we cannot get in England

Derek, thankyou for the information about the UL pot. Very helpful!

I just made one of these the other day and found a great way to cut the top off the can.

I used an ordinary hand held can opener designed to cut off the can top. i positioned it so that the cutting edge was just below the can lip against the can body and the gear that propels it was resting on the can top. it made a perfect cut in only 2 passes going slow and pressing soft. then i used scissors to cut the can to the proper dimensions.

I have done it with a razor in the past and found it took a very long time, this was fast and easy!

I did the same thing, but I took a pair of needle nose pliers and folded over the sharp edge just a touch after cutting, making a nice edge to drink from.

Dont know if you guys have tupperware in the US, but here in Aus they have a really great can opener that takes the top off and the seam, leaving no sharp edges on either. It may work.

i made a few of these beer buddies now and i really like them. I've made them out of both fosters and hienie cans and the hienie feels like it will last longer. The other thing i changed was the pat stand/wind screen. I made one like Steve'sY68VB and it worked pretty good, but i made another with no holes around most of it and a few holes and a larger fuel loading hole on one side. this allowed me to add fuel without removing the pot and helped in the wind since it was coming in from all sides.

THESE SURE ARE FUN TO PLAY WITH!!

So, I built one of these today.

I built it more for fun then to cook with.

I like a campfire. In the summer the smoke keeps the bugs away. It provides light and in the winter warmth.

Thing is I don't like burning large amounts of firewood. It's wasteful and hard to collect.

Since I also do some stealth camping I also can't usually make fires where I'm camping. Even if I can do it descretely I leave behind a fire ring which is pretty hard to hide. This is contrary to leave no trace ethics that I hold in high regard, especially when stealth camping.

I figured with a woodgas stove I can build a fire quickly in a wide variety of conditions and fuel it on very little wood for quite a while.

What finally set me off was Ryan Jordan's post about his Bushbuddy.

http://www.ryanjordan.com/weblog/2007/05/lamentation_of_.html

I won't quote it here but it's a great short read.

Every time I saw a shag bark hickory tree it reminded me of Ryan's post. Shag bark is an amazing fuel source as it burns suprisingly hot and long. It also smells great and is common in SE Michigan.

So, how'd the protype turn out?

Wow... for the most part it's great.

It's amazing how it switches over from smoking to smokeless once the top holes ignight the gasses.

Still my protype while better then expected seems to get clogged up pretty quick. My thinking is that the internal can needs more holes. And upon inspectng the original post I can see a single row or double row of holes around the bottom sides of the internal can. I only have them in the bottom in my protype.

Anything that can get more airflow through the internal can has to be a good thing.

I thought their needed to be a big hole in the bottom for ashes to fall out, but now that I've used it I realize it produces so little ash it would take several hours for the bottom of the outer can to fill enough to obscure the air holes.

In fact the full bottom makes it easy to quick light the stove with a little alchohol, which is my prefered cooking fuel. I use it with a tiny little side jet alchohol stove made out of a aluminum Budweiser bottle based off a Mini Bull Designs stove. Great stove.

I did an initial test boiling water but quickly melted the cylinderical pot support made out of a piece of spare can with lots of holes. I have some heavier aluminum I'll try next, but for me it's not about the cooking.

Am also still a little concerned about crushing the stove in my pannier bag, but it otherwise is extremely light and packs well in spare drawstring sack I had lying around.

Oh, it's suprisingly fairly clean. Sure it produces soot if I were to cook on it, but as I'm not cooking any remenent of soot remains on the inside while the outside remains clean.

All in all I think it's going to be a great tool this winter for camping in the snow and extreme cold.

I am curious if there have been any new improvements on this design or any newer designs... i.e. with a sturdier Hieneken can.

BTW, Thanks for posting!

I use a wind screen, looks like original poster does too, at least at times. It probably adds about half an ounce to the weight, but performance in the wind improves markedly. Not many people use one though. Extra holes improve performance somewhat, but adding a fan cuts the boil time in half. Depends on whether you want to be fast or light I guess.

Edited by herman666 on 10/20/2009 08:51:11 MDT.

Nice job and pictures, Steve.

Using new, but empty paint cans available at Home Depot here is another easy and efficient stove. You do not have to keep adding fuel to keep it going.

http://trailgear.org/

First, my stove is based as near to possible to the authors original design with a fosters can and bean can.

It's not a huge deal but the internal can fractured and fell off.

Ironically it fractured above the air holes I drilled in the bottom sides. Meaning they were not the week point.

Not sure if this will be a repeated problem but I'm going to continue to experiment with the design.

My big problem with this design is still the airflow problem. Since I'm not using it for cooking I'd like it to burn for prolonged periods of time with as little maintenance as possible.

When it's fairly newly lit and hasn't yet clogged with ash I can put quite large sticks in about the diameter of a quarter and it'll burn them surprisingly well. In fact better then small sticks. It only requires 3-4 of these larger sticks to produce a good flame for prolonged periods.

I suspect they burn well because of the focused heat of the stove design and large amounts of airflow around them which is impeded when you fill the can with smaller sticks.

What's more though I can't break these sticks down very small I can leave them hang out as much as six inches and they slowly settle as they burn.

The problem is it does start to clog eventually, airflow is restricted and the fire starts to smolder instead of burning hot and clean.

BTW, it's important to note that when you leave larger sticks poking out the top they are at least impeding the gasification process a little as they block the holes around the top. Thus they increase the smoke a little.

This is an acceptable trade off for me since I'm not using it as a cooking stove. Being able to use quite large sticks increases the burn time and lowers the maintenance a lot.

O ther things of note.


1) the bottom of the stove doesn't get to hot allowing the stove to be used on a picnic table with very minimal marking.

2) the stove is a little top heavy and tips over a little easy, though not disastrously. A few big rocks around it can help steady it. Obviously this is because I'm using larger sticks.

3) The stove doesn't radiate much heat out away from the can, just up. Meaning it's not great as a warming fire. Unfortunately the vertical structure is the key to getting air to flow up through the can.

4) The heat around the top of the can is pretty intense and focused... which is probably what makes it great for cooking. I find that placing a large stick or two across the top of the can that are to long to fit in it or break by hand works well. It actually seems to intensify the ossification process and quickly burns the stick through enough it can be easily snapped. This process of breaking down and burning larger sticks seems to be a great process for burning the stove long and hot... which is probably why the internal can cracked. It's possible to quickly produce an abundance of six inch sticks of 1" to 1.5" in diameter that can burn for hours and hours.


So, I think what I'm going to try next in no particular order.

1) experiment with a computer fan to increase airflow on this or another design.. Brush Buddy inspired

2) make the entire bottom half or 1/3 of the internal can absolutely full of holes to increase airflow

3) possibly leave a big gaping hole in the bottom of the internal can so that more ash falls through (if a tiny bit of still burning wood).

4) make the outer can out of a Heineken can so it's stronger.


P.S. It has occurred to me that I don't necessarily need a woodgas stove if I'm not using it for cooking. Am thinking I might try the Nimble Will Portable flat pack stove design for potentially better radiant heat... but not until I'm finished experimenting with this design.

Edited by mmeiser on 10/25/2009 13:18:10 MDT.

I made several versions of this, but was never satisfied because all needed too much attention to keep burning. I finally settled on this copy cat version of a TD Caldera Ti-Tri Inferno, made from titanium foil and weighing in at 2.15oz...



...more details at this link;

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=25085&skip_to_post=205299#205299

Have had a chance to experiment quite a bit with this design.

When I started I was just planning on using this as a winter heat source, however my last two experiments have produced some rather amazing results.

My current version now uses a tiny 12-volt computer fan at 6-volts and produces both tremendous heat and a good movement of air.

Basically the thing is like a heat gun.

Bloody amazing.

Because of the fan it now burns extremely hot, clean and consistently particularly when material becomes charcolized. The fan keeps the charcol materials red hot producing tremendous heat with no visible flames and absolutely no smoke.

Seriously... it becomes *absolutely sootless*

As long as you use dry wood of course.

It's hard to believe so I will continue to test it.

I haven't done boil tests yet but I expect they'll be very fast. Maybe rivaling iso-butane stoves like the Jet Boil.

The only negative is this sootless mode does require some time to burn down some good materials into charcol/ embers.

I find the bigger the materials... ie. 1" or 1.5" sticks the better they charcolize and the longer they'll burn as charcol.


What I found most interesting though is i could stuff (and I do mean stuff) a bunch of leaves into the stove and after smoking a whole lot, then flaring up a whole lot the leaves would become charred and produce a tremendous amount of heat for as much as 10-15 minutes with little to no smoke.

They reminded me of a mantle on the old Coleman propane lamps.

That is as long as you didn't throw anything in on top of these charcolized leaves they'd continue to burn for extended periods of time.

However if you did throw something in on top of them they would collapse into a fine powder and go out.

That said this may in fact be the quickest way to get to a clean near sootless cooking fire.

It's unbelieveable how long and hot these leaves would burn but I think I'd still prefer to cook over some much bigger chunks of charcolized wood.


Other things of note.

1) I put in a double row of hole punch holes as close together as possible around the top of the inner burn chamber.

This not only produces tremendous effective gasification (a wall of flame instead of just jets) but also in combination with the fan seems to move a lot more air in general making it a nice warming fire instead of just a nice cooking fire.

2) I put a lot more holes in the bottom of the internal can/ burn chamber. In fact I completely removed the center 1.5" of the can bottom. I then drilled holse all around this, and used a can opener to open up large triangular holes all around the bottom walls of the internal.

In my non-fan tests I actually had three rows of holes around the bottom of the internal can beause it would fill up with ash and clog. However with the fan small particulate seems to burn more quickly and thouroughly so te stove is less likely to clog with ash.

3) I switced to a heinken can.

The Heineken can holds up much better to packing and the additional heat caused by te addition of the fan.

4) How I mounted the fan.

I basically cut a 2"x2" square hole in the side of the outer can wall and then used a bit of aluminum flashing coiled into a cylinder to both hold my fan and channel the air into the wood gas stove.


5) Inner can still cracks

BTW, still having problems with the inner can flaking / cracking and eventually breaking. I may have to come up with a different alternative burn chamber.

6) Batteries

The tiny little CPU fan is 12-volts, but I am only using it with 6-volts. Specifically I'm just running it off my battery pack for my headlamp.

Have not done efficiency tests yet but I suspect te drain on my headlamp battery is negligible.


All in all my experiments have been a huge success. Though I'm still looking for ways to make a stove that packs smaller (i.e. flat pack) I've come to realize that this stove might well be able to function as both a cooking stove and heat source simply by how I use or don't use the fan.

What's next:

I intend to go through a few more iterations before posting pictures and documentation. Mostly I want to refine my craftsmanship (protypes are rudimentary), but I also want to try a 9-volt battery and see if I can't come up wit any oter improvements.

Pictures and videos to come.

I made my fire box out of paper thin titanium (0.005") from TI Goat. It's had countless fires in it. No sign of cracking or flaking. It's amazing stuff.

I'm using a 5 volt, 1.5 W fan rated at 10 CFM. I think it's way more than is necessary. I plan to try one with half that power next summer. Even so, it uses very little power. Conservatively, I can run it for 2 hours on my 2 AA NIMH cells and voltage booster.

I only use the fan until I get a boil. Then I turn it off. The natural draft is more than enough to keep a simmer going and it simmers longer without the forced draft.

I get a boil almost twice as fast as without the fan. It's not quite as fast as a canister stove, but it's close.

Looking forward to the pics and videos.

Edited by herman666 on 11/05/2009 21:10:28 MST.

"I only use the fan until I get a boil. Then I turn it off. The natural draft is more than enough to keep a simmer going and it simmers longer without the forced draft."

What kind of boil times do you get?

I'm honestly hoping I'll be able to boil about 16oz of fluid (half a Heineken can pot) in just a few minutes.

As mentioned I was definitely not expecting this stove to be practical (clean enough or hot enough) to be useable as anything more then a winter heat source. That said using forced air has blown away my expectations of how clean these things can burn and your above discription is exactly how I'm now hoping to use my stove.

I'm an alcool fan and a tiny bit of alcohol seems to get it off to a good, clean, fast and hot start with the fan which may allow me to cook on it immediately with no priming. (Just beginning to play with it.)

Voltage and flow:

I've run the 12-volt CPU fan on 6-volt and 9-volt. I don't think it takes much air volume at all. The 9-volt may be to much. Indeed with the 9-volt it started throwing sparks everywhere.

No idea whatsoever how much it flows in CFM.

I may one day actually put a dial on it to adust the flow and heat, but right now it's to early to speculate where this will go.

I am hoping btw, I can get MUCH more then two hours burn time.

I would have expected your fan to be more efficient, but I must say... my CPU fan, which I didn't think was very efficient still sounds much more efficient then your fan.

Perhaps yours is much bigger and produces much more flow then I'm picturing.


Am just about to post pictures.

Going on an overnight touring trip tomorrow and may take it as my only stove. The only thing left I have to do is create a pot holder on the top and do some testing with my Heineken can pot.

I love the my Heineken can pot as I have wrapped the whole middle section in fiberglass wicking/ insulation and can easily firmly grasp it with one hand even when boiling hot.

It's not yet good for drinking out of because I haven't figured out how to put an insulative lip or outward rolled edge on it. But it is nice to eat out of.

The only problem i've had with it is it doesn't boil or heat as fast as a wide bottom pot... meaning more fuel spent. The woodgas stove changes this equation though as I no longer need to worry about every ouce of fuel.


Packing:

I'm starting to realize if I can find the right size pot (hopefully a snowpeak titanium) I may be able to practically store the whole stove perfectly inside it so it packs compactly and well protected.

(Yes, this is to imply it's a little delecate in the pack.)

Taking into account the fact that I would no longer need to carry any fuel this makes it about half the size... maybe less then any other cook kit I've had. Even smaller then my ISO butane cook kit.

Not to mention lighter.

It's just unfortuneate that I can't store a Heineken can stove in a Heineken can pot. :( I thought about spliting one side of the stove so it can ingest the pot, but I just don't think I can make it latch together strong enough after that.

This idea that a wood stove setup could actually pack up smaller then an ISO butane setup is going to take some getting my head around.

Right now though I don't have the right pot to store my Heineken can stove in so I'll be carrying two separate little packages.


UPDATE: crap, never posted this. Sorry, running out the door.

protype: http://www.flickr.com/photos/mmeiser2/4078664881/

Video: http://www.flickr.com/photos/mmeiser2/4079433096/

finished product:
http://www.flickr.com/photos/mmeiser2/4078664649/

sorry for the lack of proofreading

I was able to boil a liter of 20 C water in a broad pan in 5.9 minutes. I think any inefficiency in my fan is due to the fact that I'm moving much more air than is necessary with my 1.5Watt fan. It creates so much surplus heat that the plastic insulation I put on the lid of my pot melted inwards about an inch.

From what I've read, about half a Watt would be sufficient. That would give me six hours of run time on the battery.

I don't care about soot on the pot. I pack my pot in a plastic grocery bag. The pot gets very sooty because I turn off the fan once I have a boil.

Click here to view the thread on my fan setup. That's a two liter pot. I cook for two.

Edited by herman666 on 11/06/2009 10:37:55 MST.