Messages abstracted from Hammockcamping group Message 1 ======================== From: "Ray Garlington" Date: Mon Sep 8, 2003 11:28 am Subject: off topic -- diy wood burning backpacking stove When hammockcamping, we all cook & eat so I'd like to call your attention to Rick's (aka geoflyfisher) wood burning, backpacking stove. The design is very clean and easy to build. Take a look: http://www.flyfisher-kayaks.com/ultralite/forge.htm I was inspired by the announcement of the early version of Rick's stove and started burning up stuff out on the patio, much to my wife's chagrin. For the last month or so, I've been smelling of smoke. My stove design has gone in a slightly different direction (no fan) but is not yet ready for prime time. I'm trying for a wood- gas, batch loaded stove weighing about 5 oz that is sufficient to boil 1 quart and hold a simmer for about 10 minutes. My current problem is if I batch load, it takes about 3 minutes before it burns clean. I need a way to increase the draft temporarily during firing. I might give up and just use Rick's design. Ray Message 2 ======================================= From: Miguel Arboleda Date: Tue Sep 9, 2003 2:52 pm Subject: Re: OT- DIY Wood Burning Backpacking Stove Hi Ray, There have been a number of discussions about wood burning stoves on the Backpacking Light discussion group, with quite a number of people taking stabs at making their own, Shane Steinkamp being a notable example. Personally I have been most interested in the Inverted Downdraft Gasifier stove. See some examples here: Here's an explanation: http://www.repp.org/discussiongroups/resources/stoves/Reed/Turbo2.htm http://journeytoforever.org/teststove.html (the central ventilating tube down the center of this one might answer your drafting problem) http://journeytoforever.org/at_woodfire.html This is the US patent office's description of the now defunct BushBuddy Stove: http://patft.uspto.gov/netacgi/nph- Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/ srchnum.htm&r=1&f=G&l=50&s1=5,842,463.WKU.&OS=PN/5,842,463&RS=PN/ 5,842,463 Then there's this simple contraption: The Trailstove: http://www.trailstove.com/ Hope this can give you some ideas to work with. Miguel Message 3 ============================= From: "Ray Garlington" Date: Tue Sep 9, 2003 4:04 pm Subject: Re: OT- DIY Wood Burning Backpacking Stove --- In hammockcamping@yahoogroups.com, Miguel Arboleda wrote: > Personally I have been most interested in the Inverted Downdraft > Gasifier stove. > Yes, me too. This is what I am shooting for, since it lends itself to a relatively-compact vertical package. > http://journeytoforever.org/teststove.html (the central ventilating > tube down the center of this one might answer your drafting problem) > I had not seen this link before. It is very interesting and is in the same vein as what I am trying. Yesterday I had very good success forcing all the primary air through a relatively small central air hole in the burner assembly. > This is the US patent office's description of the now defunct BushBuddy Stove: Note to others trying to look at this patent: just go to the patent office site (http://patft.uspto.gov) and look up patent #5842463 It is very surprising that this patent was issued. The processes associated with wood gassification have been known far before 1998. I think you can find prior art for all his claims. > Hope this can give you some ideas to work with. > Thanks Miguel. Very interesting stuff. I continue to make progress and should be able to get a fairly good example going soon. Message 4 ======================== From: Matthew Takeda Date: Wed Sep 10, 2003 3:06 am Subject: Re: off topic -- diy wood burning backpacking stove Ray Garlington wrote: >... I'm trying for a wood- >gas, batch loaded stove weighing about 5 oz that is sufficient to >boil 1 quart and hold a simmer for about 10 minutes. My current >problem is if I batch load, it takes about 3 minutes before it burns >clean. I need a way to increase the draft temporarily during firing. > >I might give up and just use Rick's design. Don't give up. I'm trying to do the same thing, although I haven't set a target weight. I figure I need to get the design working first, then lighten it. Tom Reed's Biomass Energy Foundation just started selling their small gasifier "campstove" about a month ago. It uses forced convection from a fan powered by a single AA battery and is fairly impressive, but it weighs in at 30 ounces. Natural convection should work fine once it gets going. What are you using as a firestarter? I've been using a few drops of alcohol. Do you route the intake air to preheat it? For starting, you could go two ways (off the top of my head, which usually means there are more that I've overlooked ...): an add on chimney to increase draft, or a tube you blow through until it gets going. - Matthew Takeda - the JOAT Message 5 ======================================== From: "Ray Garlington" Date: Wed Sep 10, 2003 9:33 am Subject: Re: off topic -- diy wood burning backpacking stove --- In hammockcamping@yahoogroups.com, Matthew Takeda > >>> Don't give up. I'm trying to do the same thing, although I haven't set a target weight. I figure I need to get the design working first, then lighten it. Thanks for the encouragement. I have two things in mind for this project, the small lightweight burner which I will then scale up to a patio burner. The larger burners are easier because the draft is so much stronger. > Tom Reed's Biomass Energy Foundation just started selling their small gasifier "campstove" about a month ago. It uses forced convection from a fan powered by a single AA battery and is fairly impressive, but it weighs in at 30 ounces. For those that haven't seen this yet, there are some pictures and some explanation here: http://www.woodgasllc.com > Natural convection should work fine once it gets going. What are you using as a firestarter? I am using a miniature candle, which is a 1/2" wick on a square of cardboard (about 1/2" x 1/2") with about 25 drops of parafin. > Do you route the intake air to preheat it? In my current attempts the intake air is coming in under the fire box and is forced through a 1.25" diameter opening in the bottom of the firebox, where there is a wire screen to disperse the air and allow the ash to drop through. This creates a very hot, but small fire just above the hole. I will be refining this over the next week, and expect to end up with separate controls for primary & secondary airflow. One of the design goals is that this must be easy and fun to start which is the current weakness. > >an add on chimney to increase draft, or a tube you blow through until it gets going. Yes, right now I'm doing both of these. The add on chimney is the most satisfying; but the complexity/bulk of possibly telescoping tubes is weighing against this as a solution. On the other hand, there will be a windscreen involved, so perhaps that could be made to do double duty. > Thanks for your comments Matthew! Message 6 ================================ From: Matthew Takeda Date: Sat Sep 13, 2003 1:52 am Subject: Re: off topic -- diy wood burning backpacking stove BTW, if you haven't done so already, I would suggest you look throught the archives of the stoves list and the gasification list at repp. - Matthew Takeda - the JOAT Message 7 ================================ From: "Ray Garlington" Date: Tue Sep 30, 2003 12:01 pm Subject: off topic -- diy wood burning backpacking stove I have continued messing with this and have a configuration that might be useful to fire enthusiasts. I will continue refining this design, but don't expect to uncover major improvements. As with the Garlington Insulator, I will put together a web page with some pictures and additional detail. Comments are welcome. Thanks, Ray ------------------ The Garlington WoodGas Stove After about 2 months building & testing small woodstoves of various configurations, I stumbled on an easy to build, lightweight stove (3.5 - 4 oz) that will boil 1 quart of water and hold the boil for about 10 minutes. The stove is batch loaded, fun to use, and nearly smokeless when properly fired. On the negative side, this stove requires a starter fluid and will blacken your pots. Also, the current version gets hot enough at the end of the burn to ignite newspaper under the burner, so the stove should not be used on flammable surfaces. The design attempts to exploit the "batch-loaded, inverted down-draft gassifier" wood-burning technique and manages about 1/3 - 1/2 "blue flame" at peak output. As the gas-burning stage winds down and while the stove is still quite hot, the flame is mostly blue. Typically, the stove is burning wood gas shortly after ignition and has a stable yellow/blue flame within about 1 minute. After about 10 minutes the wood gas is depleted and the stove transitions to charcoal burning. Charcoal burning continues for about 20 minutes after this transition. Description The stove comprises a steel can, fire grate, stove windscreen, pot stand and pot windscreen. The steel can forms the body of the burner and is 3" in diameter and 4 1/2" tall. Primary air holes are punched at the bottom edge of the can, and secondary air slits are cut about 3" up from the bottom. A fire grate (wire screen) is fitted to the bottom of the can to allow even distribution of the primary air to the bottom of the fuel supply. The stove windscreen is made of light aluminum (disposable baking pan) about 3 1/2" in diameter and 4 1/2" tall. Slots are cut in the bottom of the stove windscreen to allow primary/secondary air to enter. The pot stand is fashioned by bending a coathanger into a clip that slips onto the rim of the steel can and holds the pot about 1 1/4" above the rim. The pot windscreen is a piece of doubled aluminum foil that goes from the ground to at least 1/2 way up the pot. Operation Find a supply of dry sticks about the diameter of a #2 pencil and smaller. Dump out the ash from the previous firing, and position the stove windscreen and pot stand on the stove body. Break up the sticks into about 1" lengths and throw them into the burner. As the stove fills, periodically shake/tap the stove to settle the fuel. When you get close to the secondary air slits, use only the smallest of the sticks you have collected. Shake/tap down the stove once again. Spray a small amount of starter fluid (charcoal starter fluid, kerosene, alcohol, etc.) on the top surface of the wood supply. Do not use too much, because you only want to ignite the top layer of wood. (Igniting the lower layers will result in a smokey mess.) Light the starter fluid. After about 1 minute you should have a good flame going. Postion the pot on the stand and place the pot windscreen around the pot. Caution: If the stove fails to ignite, do not spray additional starter fluid. There will be hot embers present from your previous attempt which are capable of igniting the fluid as you spray it on. This could result in SEVERE injury to you and others. The safe thing to do is unload the stove, reload it, and try again. Copyright 2003 Ray Garlington ----- Tests: Test 9/29/2003 Air Temp: 55F Starting water temp: 71F Time Comments 0 Light fire 1 min Water on Stove 5 min Water temp 130F 10 min Boiling 20 min Boiling 25 min 198F 30 186F Charcoal is generating little heat.... Message 8 ============================= From: "Ray Garlington" Date: Wed Oct 1, 2003 1:45 pm Subject: Re: off topic -- diy wood burning backpacking stove --- In hammockcamping@yahoogroups.com, "Ray Garlington" wrote: > I will put together a web page with some > pictures and additional detail. Comments are welcome. see: http://raygarlington.50mb.org/WoodGasStove/WoodGasStove.htm Message 9 ======================== From: "Coy" Date: Thu Oct 2, 2003 12:24 am Subject: Re: off topic -- diy wood burning backpacking stove Hi Ray Thanks for sharing. I was trying to imagin where the fire grate (screen) goes. I assume just above the bottom primary air inlets but a quote from the "description section says "A fire grate (wire screen) is fitted to the bottom of the can to allow even distribution of the primary air to the bottom of the fuel supply." It does go up from the bottom about an inch, right? Also how do you attach the grate? I am impressed that it will burn so long on one 2 oz load of fuel. I was expecting it to need reloaded like i hear the Zip and other similar stoves need. I also like that it dosent need a battery. I'm guessing the liquid fuel pre starter serves a similar function in getting it going good then drafting takes over. What can are you using. I have a maxwell house coffe can which would probably work great. I might even leave it tall and use part of the can for pot supports. It is 4 inches across and 7 inches tall. I would put the primary air inlets around the bottom, the grate just above that, the slits for secondary air about mid way up the can and cut the top down about 1 inch leaving 4 prongs about half an inch wide for a pot support. I really like no fan or battery to worry with. Coy Boy Message 10 ================================ From: "Ray Garlington" Date: Thu Oct 2, 2003 8:08 am Subject: Re: off topic -- diy wood burning backpacking stove --- In hammockcamping@yahoogroups.com, "Coy" wrote: > I was trying to imagine where the fire grate (screen) goes. You need about 1/8" to 1/4" of air space at the bottom of the can. I just used multiple layers of folded chicken wire and pushed it down to the very bottom of the can. You have enough space if you can look through one of the primary air holes and see light through the opposite one. > I am impressed that it will burn so long on one 2 oz load of fuel. Yes, it surprises me too. Also, no smoke! which is also a nice surprise. > I was expecting it to need reloaded like i hear the Zip and other > similar stoves need. If you do reload this stove as it burns down, it will smoke. It is probably better to size the burner to the amount of heat you will need rather than try to reload one that is too small. > What can are you using? I'm using a small can that vegetables came in. It is 3 inches in diameter and 4 1/2 inches tall. > I have a maxwell house coffee can which would > probably work great. This can is much bigger than the one I used. It will generate a lot more heat and will require more wood. Let me know how it turns out. Message 11 ============================== From: "Shane Steinkamp" Date: Fri Oct 3, 2003 12:02 am Subject: RE: Hammock Camping Re: off topic -- diy wood burning backpacking stove > > I will put together a web page with some > > pictures and additional detail. Comments are welcome. > > see: http://raygarlington.50mb.org/WoodGasStove/WoodGasStove.htm I'm WAY behind in the list, but I just thought I'd say that I am very excited about this one Ray. I've thought for a long time that a simple gasifying wood stove would be excellent for backpacking. Can you provide an image for the screen? The construction isn't clear on that point. Thanks! Shane Steinkamp Message 12 ========================= From: "Dave Womble" Date: Fri Oct 3, 2003 8:15 am Subject: Re: off topic -- diy wood burning backpacking stove Yeah, I agree totally with Shane, that is some neat stuff that Ray is doing with his stove. For what it is worth, I came across a great reference on stove designs: "The Training Manual for Cookstoves" by the Peace Corp. It has some great info about stove designs, efficiencies and how they actually work. It has a well layed out table of contents that allows you to go to the particular subject that you are interested in. When I looked at it, I could see clearly why the "real Trangia stoves" were so efficient and also why my Japanese Komono grill works so well. It showed me what I had already discovered: the efficiency of homemade backpacking stoves is not so much in the burner design, but in the design of "all the things that make up the stove"; for the popular alcohol stoves it would include the bottom reflector, preheat pan, burner, stove stand, wind screen and the pot-- the best stove is one in which the dimensions of all these things are designed to work together. Anyway, if you are interested the Peace Corp stove manual can be found at http://tinyurl.com/pkju Like I said, it has some great info about stoves and how they work. And Ray, keep up the good work and don't fret about using alcohol to start your stove-- it is good to have for other purposes anyway, like as a disinfectant for your hands. Youngblood Message 13 ======================= From: "Ray Garlington" Date: Fri Oct 3, 2003 9:42 am Subject: Hammock Camping Re: off topic -- diy wood burning backpacking stove --- In hammockcamping@yahoogroups.com, "Shane Steinkamp" wrote: > I'm WAY behind in the list, but I just thought I'd say that I am very > excited about this one Ray. I've thought for a long time that a simple > gasifying wood stove would be excellent for backpacking. > Shane, Thanks for your interest. The stove is really quite convenient and fun once you get the hang of it. At 4 oz, it is good for backpacking where dry fuel will be available (or be collected and dried). I would like to improve the bottom insulation somewhat so that it can be used on flammable surfaces (like a picnic table). > Can you provide an image for the screen? The construction isn't clear on > that point. Yes, I neglected this point, but won't be able to take pictures & update the page until probably monday. If you want to try it before then, just get some chicken wire, rabbit wire or similar and fashion a grate that will keep the wood off the bottom of the can. That way air can circulate under the fuel charge. There is nothing tricky going on there. In fact, there is nothing tricky going on at all, except the non-intuitive idea of loading the stove and igniting the top of the fuel! If you have the materials, you can make the stove in about 5 minutes. Ray Message 14 ========================== From: ra1@i... Date: Fri Oct 3, 2003 10:39 am Subject: Re: Hammock Camping Re: off topic -- diy wood burning backpacking stove Ray, Great reading on this little stove you have designed. The weekend promises some time to try it out. A few questions: Have you tried lighting it with pine needles or paper as some suggest, instead of the liquid? Effects of wood that is not quite dry? I assume the stove windscreen is causing some of the air/smoke from the secondary slits to be pulled under the stove in a preheated way and to burn the wood gas. Do I have this right? Rick Message 15 ======================== From: "Ray Garlington" Date: Fri Oct 3, 2003 11:11 am Subject: Hammock Camping Re: off topic -- diy wood burning backpacking stove --- In hammockcamping@yahoogroups.com, ra1@i... wrote: > Have you tried lighting it with pine needles or paper as some suggest, instead > of the liquid? I want to try lighting with tender, but have not done so yet. I was also thinking of some sort of fabric dipped in wax that could be layed on top of the fuel charge. > > Effects of wood that is not quite dry? > The more wet and the more green the wood the more difficult starting is (more fluid must be used). Also, when the stove transitions to charcoal burning, wet/green wood tends to smoke. So far, blowing down on the coals has added enough air to hasten the transition back to smokelessness. > I assume the stove windscreen is causing some of the air/smoke from the > secondary slits to be pulled under the stove in a preheated way and to burn the > wood gas. Do I have this right? The stove windscreen acts as insulation for the comubstion chamber and heats the primary/secondary air. Concerning the secondary air inlets, all that happens there is that additional, slightly pre- heated fresh air is drawn into the combustion chamber. If you look carefully on the picture of the stove body, you will notice that the bottom of the secondary-air slit has been pushed toward the center of the can. This creates a small venturi that draws in more air (this seems to help). On my current stove, I have cut four additional secondary slits, two ridges higher & halfway in between the slits shown in the picture. Don't know if they help much (or any for that matter). Message 16 ================================== From: ra1@i... Date: Fri Oct 3, 2003 1:40 pm Subject: Re: Hammock Camping Re: off topic -- diy wood burning backpacking stove Ray wrote: > > I want to try lighting with tender, but have not done so yet. I was > also thinking of some sort of fabric dipped in wax that could be > layed on top of the fuel charge. > > Yes, I am thinking of the little strips of cardboard soaked in candle wax that "NoDrip" told me about on the AT. I have been using them for fire starters ever since. They are non-volatile, can't leak, and burn very well. I have also been doing some thinking about ways to decrease the weight and pack footprint. I love your concept and look forward to trying out the original and some mods over the weekend. I did go out and look up several of the web references to the downdraft stoves. You did a great job of turning those heavy items into something which can be used for backpacking! Rick Message 17 ============================= From: "Ray Garlington" Date: Fri Oct 3, 2003 3:53 pm Subject: Hammock Camping Re: off topic -- diy wood burning backpacking stove --- In hammockcamping@yahoogroups.com, ra1@i... wrote: > I have also been doing some thinking about ways to decrease the weight and pack > footprint. I love your concept and look forward to trying out the original and > some mods over the weekend. > > I did go out and look up several of the web references to the downdraft stoves. > You did a great job of turning those heavy items into something which can be > used for backpacking! > > Rick Thanks for your comments. Have fun & let me know what you find out. Ray Message 18 ====================== From: "Risk" Date: Sun Oct 5, 2003 6:34 am Subject: Hammock Camping Re: off topic -- diy wood burning backpacking stove Three stoves into this project, I have learned a few things already. - the stove works - I have been able to get it to work with paraffin soaked cardboard, but not with much weight savings over the half teaspoon of lamp oil or coleman fuel it takes to get started. - One nice thing about the stove is that it can be started with just about any fuel. This is a plus for finding a source of fuel anywhere. - I tried a version with windows cut in the top 3/4 inch of the can. It is not tall enough to create enough draft. It did not work - I tried a very light version made from sheet brass and aluminum. This works pretty well and fits inside my small pot. However it is more fragile and not quite as stable. It also must be used where metal sticks can be inserted in the ground. I will post some pics of this when I have the weights available. - I replaced your bottom screen with a piece of hardware cloth. It sits on four tabs that are bent up instead of down. I cut the openings for the cuts with a dremmel drill. - I am getting boiling times a little shorter than yours. It takes about 5-6 minutes to boil 2 cups of water, and the water boils for about 8-10 minutes. It does stay hot for many more minutes, because of the charcoal heat. - I had trouble with the pot stand sticking to the pot. I came up with a lighter-weight alternative with less contact area. - I can already see that I would be willing to take this little stove hiking for a longer trial. Great work Ray! Rick Message 19 ====================== From: "efield" Date: Sun Oct 5, 2003 6:58 am Subject: Re: off topic -- diy wood burning backpacking stove I have a couple of questions. 1. Ray said in his earlier posts that the larger the diameter the can, the more heat was produced. Has anyone come up with an otimum diameter for a backpacking stove. 2. Does the height of the fuel load have much affect on the total burn time? Would a taller stove give longer burn times? Great work to all who are testing these stoves. Ed Field Message 20 ====================== From: "Risk" Date: Sun Oct 5, 2003 8:07 am Subject: Re: off topic -- diy wood burning backpacking stove Ed, Ray will post his own reply, but I believe that he has found a pretty optimum size. This may be about as small as the stove can be and still be self sustaining. He used, and I copied, a stove made from a tin can which is 4 3/8 in (11.1 cm) tall and 2 7/8 in (7.4 cm)in diameter. This is a common can size for many vegetables in the US. From reading the literature, a taller stove does give a longer burn time. But for most backpack cooking this is a pretty good time. I did find yesterday, that if I wanted to increase the time, I could add another batch of small sticks when the stove enters the charcoal phase and it would be back to gassifying very quickly. This burn is not quite as efficient, because the heat is below the sticks and not working its way down through them. I am interested in seeing what Ray has to add to this. BTW, There is a small chance we should think about moving this discussion to another group as it has been staying off hammock camping for quite a while. How about BPL? Ray? Rick Message 21 ==================== From: "Shane Steinkamp" Date: Mon Oct 6, 2003 12:24 am Subject: RE: Hammock Camping Re: off topic -- diy wood burning backpacking stove > There is a small chance we should think about moving this > discussion to another group as it has been staying off hammock > camping for quite a while. How about BPL? Ray? I have a couple of things I'd like to add too, but I'd like to see us move it first. Anywhere you like... Even off list if need be. Might be a good time to create the 'woodburningbackpackingstoves' list on Yahoo... Shane Message 22 ======================== From: "Shane Steinkamp" Date: Mon Oct 6, 2003 12:33 am Subject: RE: Hammock Camping Re: off topic -- diy wood burning backpacking stove > Might be a good time to create the > 'woodburningbackpackingstoves' list on Yahoo... Well, here's: http://groups.yahoo.com/group/BackpackingStoves/ Shane Thread moved ===================