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MYOG – A Winter Canister Stove using your Summer Upright Stove and the Brunton Stove Stand


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Home Forums Gear Forums Make Your Own Gear MYOG – A Winter Canister Stove using your Summer Upright Stove and the Brunton Stove Stand

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  • #1456215
    Matt Lutz
    Member

    @citystuckhiker

    Locale: Midwest

    Thanks for the thoughts – I'm probably going to make this in the next few weeks and use it for at least fringe seasons. I have been using a Dragonfly for my primary winter snowmelter, but I would love to shave 10 oz off my winter stove weight.

    #1456255
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    Hi Steve

    > As in wrapping the canister with sleeping pad material and covering the "bowl" with the water in it with a piece of silnylon or something?

    Anything like that. A 'cozy' covering the top and sides and made from bubble wrap would probably do. Just stop that evaporation!

    I gave Sue some luke-warm water one morning in the snow so she could wash our plastic breakfast bowls out. She rinsed them clean, put them down wet and went looking for our mini-teatowel to dry them. By the time she had found it, the water left in the bowls had frozen! All she had to do was tap the plastic bowls so the ice fell out, and they were dry. Thus evaporation heat loss!

    Another way of handling the problem is to leave the windshield around the stove open for a few inches and to position the canister near the opening in the windshield, so it gets a bit of the hot air and radiation from the stove. Needless to say, with this trick you MUST sit there and monitor the temperature of the canister. Luke warm is what you want; hot is absolutely NOT.

    How much hot water, replaced how often? Depends very much on the conditions (and any evaporation loss). The key thing to remember here is that there are huge differences between using an upright and an inverted canister, thus:
    * With an upright the gas is boiling inside the canister and the energy for this comes from the canister – so it chills down fast. You have to keep pumping in more energy or the canister will chill too far to boil.
    * With an inverted canister there is almost no evaporation at all inside the canister: it happens at the stove using heat from the flame. So the canister does not chill down quickly. Get it warm and it will stay warm, barring external heat loss.

    Cheers

    #1456263
    Bill Fornshell
    BPL Member

    @bfornshell

    Locale: Southern Texas

    It is really to bad this site has no real search function. There are so many great MYOG threads hidden away in the closet here.

    Or could it just be lazy members?

    Make A Canister Cozy 08-24-2005

    The wheel just keeps getting re-invented and re-invented.

    #1456264
    Bill Fornshell
    BPL Member

    @bfornshell

    Locale: Southern Texas

    Inverted Canister Stove – 01/04/2006

    Inverted Canister Stove

    #1456391
    Brad Groves
    BPL Member

    @4quietwoods

    Locale: Michigan

    Roger-

    I guess this is a more appropriate thread for questions about the gases–

    * With an upright the gas is boiling inside the canister
    then
    With an inverted canister there is almost no evaporation at all inside the canister:

    I'm feeling slow here. But this is comparing two different things, right? Boiling in one canister, evaporation in the other? Except the gases couldn't actually evaporate unless they escape the canister, right? I asked on the other thread if the simple inversion of the canister actually changes the physics and separation of the gases–this makes it sound like it does! I sure like the sounds of it staying warm once warmed, though.

    Bill, I don't think it has anything to do with lazy members. I know I've read all the old pertinent threads–shoot, everyone's remote canister set-ups and your Balrog inspired me to start creating my own! But I like how conversations here continue to develop and explore things from slightly different angles, too.

    #1456408
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    Hi Brad

    Replied on other thread. Yes, quite different fuel delivery systems.
    http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=16401&disable_pagination=1

    You are right about the confusing use of 'boiling' and 'evaporation'. I use 'boiling' to mean that lots of vapour is coming off, as in an upright stove or water boiling in a pot. With an inverted canister there is a high internal pressure from the gases, but the vapour at the top of the canister does not escape. I used 'evaporation' for the process of creating the pressure: it is similar to pumping a WG fuel tank.

    Cheers

    #1457477
    Mark Ferwerda
    BPL Member

    @mnferwerda

    Locale: Maryland

    I thought that I would share this with you all. One thing that was lacking here was a convenient way to invert the canister. I took a canister stand made by Primus and adapted it to work with the Brunton stand. The design of the Primus stand worked well here because I was able to center the canister attachment part of the Brunton stand on the top leg since the leg itself comes out from the side. Basically what I did was:

    filing of leg
    1 – Use a round file to file a groove in the top Primus leg to fit the top of the canister adapter

    gluing leg to canister connector
    2- Used some epoxy to glue the adaptor to the leg.

    stripped down legs
    3 – Removed the excess plastic from the other legs so that it all would fold together.

    zip tie
    4 – Finally I used a zip tie to minimize the stress on the epoxy.

    The weight of the Brunton stand was 5.4 oz. The total weight when I got done was 6.0 oz. I did file some of the excess metal from the steel legs from the stand for the stove.

    all together
    Here is what it looks like all folded up (yeah it is a big screw isn’t it).

    #1459558
    Matt Lutz
    Member

    @citystuckhiker

    Locale: Midwest

    I put everything together, and am having a few problems. I am using an MSR PocketRocket, but that shouldn't matter. My block parts and fin were made of brass, the screw was steel. The blocks were made it out of one piece of brass and drilled the holes before cutting it in half. The rod I put inside the brass tube was about 1.8 or 1.9 mm. There is a slight gap between the blocks (more so on the top). I was using Snow Peak canisters, and all of my testing was done in temps in the mid to low 20s (F). I did however, throw the canisters in the freezer to cool them and better simulate winter conditions before the testing began. Each test lasted about 10 minutes.

    I cannot get the gas to vaporize properly. When the canister is upside down, I get a continuous fireball, even on very low power. Even after the stove heats up and the upright fin appears to be warm, but it does not appear to be vaporizing the gas.

    To try to correct this, I added some thermal compound between the blocks and between the fin and one of the blocks in an effort to increase heat transfer. This did not work, and the stove never settled down.

    Also, I can settle the flame be leaning the canister slightly while upside down. I am using mostly-empty canisters. However, as soon as I tip the canister fully upside-down, the stove fireballs again.

    As I see it, I can cut a new blocks and hope for a better fit and/or make the fin out of copper to increase heat transfer. I also think I should add a thicker rod inside the brass tube to decrease gas flow.

    Any suggestions?

    #1459583
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    Wow!
    Elegant!

    Roger

    #1459584
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    Hi Matt

    > When the canister is upside down, I get a continuous fireball, even on very low power.
    > Even after the stove heats up and the upright fin appears to be warm, but it does not appear to be vaporizing the gas.
    > My block parts and fin were made of brass

    I have had this problem myself too. I found that the brass strip I had installed was simply not conductive enough. I swapped over to a copper strip (lying on the bench …) and the arrangement worked fine.
    Have a look at this page
    http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html
    You will see that the thermal conductivities of relevant metals are:
    Brass 109 W/(m.K)
    Aluminium 255
    Copper 400

    Brass is only 1/4 as conductive as copper. So while using brass for the solid block is OK, you have to use copper for the fin. You could try thick aluminium if you like (1/16" maybe) but there is always the risk of melting it.
    You could also try a hard Al alloy for the block if you have some.

    > I also think I should add a thicker rod inside the brass tube to decrease gas flow.
    Secondary imho.

    Cheers
    Roger

    #1459597
    Matt Lutz
    Member

    @citystuckhiker

    Locale: Midwest

    Thanks – I'll make the fin out of copper and report back.

    #1459799
    James D Buch
    BPL Member

    @rocketman

    Locale: Midwest

    tbeasley wrote:

    >Ti is an amazing material that solves many problems; weight, strength, corrosiveness, durability, heat weakening. But poor heat conductivity makes it a poor choice for a cooking pot. Thin aluminum pots easily outperform Ti pots when you weigh in the extra time and fuel consumed

    I thought the same before I did some tests, I could not make Al pots perform better than my Ti pot, this was true with alcohol and canister gas. Below is a graph of my results and the points are boiling time for different flame settings. SS even performed better than Al.

    Tony

    Pot Efficiencr graph

    If the graph came through, the small study shows that if you want minimum fuel consumption, use of a four minute boil or so is much more important than the choice of pot material — at least between Stainless Steel, Aluminum and Titanium.

    This conclusion probably doesn't encompass the inclusion of heat exchanger devices attached between the burner flame and the pot. It makes sense that heat exchangers would increase the efficiency, and someone (JetBoil)has probably done tests to demonstrate this.

    #1460133
    elias heyns
    Member

    @chiefcrazytalk

    i haven't used a remote canister stove in the winter yet, but i do know that i can stop my stove (primus micron) from performing poorly in cold weather by holding the canister. obviously this warms the canister (and freezes my hands) and i get dinner in a reasonable amount of time.

    my question is why wouldn't you be able to put a longer hose on the adapter and throw the canister in your sleeping bag. the temp in there would be way above freezing.
    is there something i'm missing about the whole thing?
    sorry if it was explained before.

    #1460147
    Rick Dreher
    BPL Member

    @halfturbo

    Locale: Northernish California

    If you're in the sleeping bag with the canister it would keep it warm and maintain fuel pressure. I don't know how much the vapor would cool in its path through the long hose, however. I also don't konw how much fuel you'd lose in a long hose, between uses.

    In an unoccupied sleeping bag the effect would eventually be the opposite, as the bag would insulate it while it naturally cooled and it would freeze up. You'd be better off stuffing it into your jacket.

    #1460150
    Rick Dreher
    BPL Member

    @halfturbo

    Locale: Northernish California

    I have to agree. The material in titanium pots is so thin that conductivity differences have a minimal affect on heat efficiency. Ti pots do exhibit hot spots, which makes cooking on them trickier than aluminum, but for boiling water there's no effective difference.

    Same thing for plain metal versus black-painted–no appreciable difference.

    #1460194
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    > I don't know how much the vapor would cool in its path through the long hose, however.
    Actually, the temperature of the hose does not matter at all. As long as there is pressure in the canister to drive the gas out of the jet, that is enough.

    > I also don't konw how much fuel you'd lose in a long hose, between uses.
    Yeah, a problem in principle, but most hoses are actually filled up with something to reduce the volume down to a reasonable level. Think of the heavy SS cable in the big fuel lines of some MSR white gas stoves. The effect is there, but it is not quite that great.

    Cheers

    #1460352
    Paul Tree
    Member

    @paul_tree

    Locale: Wowwww

    I thought it was an interesting fact that Roger Caffin posted:
    -20 C is the cutoff for 30/70 canisters. Much weight, time and effort has been dedicated to keeping the canister off the snow, but if air temps are much below freezing and snow is (ideally) 0 degrees, might it make sense to make contact between cylinder and snow?
    Snow surface temps are usually below zero in reality due to radiative and evaporative cooling, so may not work in real life, but made me curious…stove in ice

    Looks like there is some orange in the flame. It it is on pretty high (sorry, not very scientific) with about 3 MPH wind. Some orange flame is normal if run on high, but this seems just a bit more. As long as the gas gets out of the canister to the hot stove, it shouldn't be actually wasting any power, right? Although you'd be burning a higher percent of propane. Maybe just propane?

    "Propane is more suited to colder environments since it evaporates at -44oF (-42oC) at atmospheric pressure. Butane evaporates at 33oF (-0.5 oC) at atmospheric pressure."

    Doh.
    stove in ice on fire

    #1460418
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    I LOVE IT!

    May I ask for permission to use this photo (somewhere, with acknowledgement), PLEASE!

    Now to the question of why this works. Several steps.

    The MSR red canister contains iso-butane, which has a boiling point of (roughly) -11 C, and propane, with a boiling point of about -42 C. This canister will work to about -24 C in liquid feed mode.

    In the photo the stove is chugging along happily while the canister is embedded in ICE! I am going to guess that you froze the lot in an ice-cream tub in the freezer? So what temperature is the ice at in the photo? My guess is that it might be somewhere between 0 C and -4 C, what with the warmth of the sun etc. Note: this is well above the boiling point of iso-butane!

    Finally, let's look at what the block of ice is doing. It is in GOOD thermal contact with the canister. The fuel inside is boiling away and would be cooling down, except that the huge mass of ice is busy pumping energy into the canister. I would guess that the stove is burning both propane and iso-butane (but I am not sure at what ratio).

    This is (one reason) why MSR puts iso-butane rather than n-butane in this canister: it will function at temperatures slightly below freezing, and for many walkers that is as cold as they get. The downside is that the canisters are dearer than commodity 70% n-butane ones. Well, you pay your money and take your choice.

    Cheers

    #1460457
    Paul Tree
    Member

    @paul_tree

    Locale: Wowwww

    Glad you like it Roger, it seemed like a true BPL pic.
    If you want, I have a few more full size photos and maybe they are better. PM me an email address if you like, use them as you wish.

    I had been assuming it would be at zero so I didn't even measure! There was just a smidge of unfrozen water in the ice, and once the stove started, it could be spun around freely and did not refreeze when extinguished. Also missing is testing of boiling times. I boiled a cup of water outside and timed it, but realized two of the same stoves were needed at the same time, one frozen and one not, to get the clearest results.
    As well as 2 of the same pot and lids in good shape.
    As well as a ventilated yet more wind-sheltered test area, eg garage with door open.

    It would also be good to run it through a whole canister and see if there is degraded performance towards the end.
    Couldn't bring myself to just let it keep burning though.

    In snow, you could take off the top coldest layer of snow and get to some -2C snow. If anyone does this, try embedding an led light in the ice as well to illuminate the night shot.

    #1463709
    Matt Lutz
    Member

    @citystuckhiker

    Locale: Midwest

    Over-arching question – how will using the stove stand affect stove efficiency i.e. how will it affect the amount of fuel used per pint of water boiled/snow melted?

    Testing of the PocketRocket, and other can stoves, was done by BPL in this thread: http://www.backpackinglight.com/cgi-bin/backpackinglight/lightweight_canister_stoves_test_report.html. Note that the gas cans and the stove were cooled to 10F before testing. The curious thing about this is that the PR was run at max flame, but fuel consumption decreased because the stove was running at a slower pace. "Under cold conditions (column 4), fuel consumption decreased because the stoves burned more slowly (equivalent to a moderate flame), even though they were set at full throttle." (under Table 2). Given that, is it advisable to run the stove at full throttle? If so, at what temps?

    Second: If isobutane has a boiling point of 10F, do I need to turn the canister upside when temps are above 10F? In testing in approximately 30 degree weather, the flame increased dramatically when I turned the canister right-side up.

    Third: Also, how does temperature and canister position affect which fuel (isobutane or propane) is burned?

    Thanks as always.

    #1463730
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    > how will using the stove stand affect stove efficiency
    Complex.
    If you have the pot at the optimum height you will get 'good' efficiency. Raising the pot a foot is obviously going to seriously reduce the efficiency (out the window in fact!). Lowering the pot right onto the burner is going to quench the flame a fair bit and this too will reduce the efficiency a bit – but not as much.
    But then questions of wind speed come in, as Will's article shows.
    Far more important is the fact (imho) that when the pot is too close the amount of CO generated rises significantly. This was discussed at huge length in the CO series of articles.

    > fuel consumption decreased because the stove was running at a slower pace
    Absolutely. Running a stove flat out wastes a whole lot of heat up the side of the pot. Running it at about half power is far more efficient and heats the water almost as fast. I never run my stoves flat out, under any conditions (except for lab stove testing!).

    > If isobutane has a boiling point of 10F, do I need to turn the canister upside when temps are above 10F?
    By and large, it makes sense to use the canister upside down. Otherwise the propane tends to preferentially evaporate. OK, if its 60 F there's no problem, but if you are using the Brunton Stand in cold weather it makes sense to invert.

    > In testing in approximately 30 degree weather, the flame increased dramatically when I turned the canister right-side up.
    I don't understand this. Usually the flame increases when the canister is inverted. I suspect a blockage or the valve was knocked.

    > how does temperature and canister position affect which fuel (isobutane or propane) is burned?
    Read through the other articles on canister stoves I have written: it is all there in great detail. The Series on Winter Stoves will be most helpful:
    Selecting a Canister Stove for Cold Weather Backpacking
    Part I: Stove and Fuel Fundamentals
    http://www.backpackinglight.com/cgi-bin/backpackinglight/selecting_stoves_for_cold_weather_part_1.html

    Selecting a Canister Stove for Cold Weather Backpacking
    Part II: Commercially Available Canister Stove Systems
    http://www.backpackinglight.com/cgi-bin/backpackinglight/selecting_stoves_for_cold_weather_part_2.html

    Cheers

    #1463755
    Matt Lutz
    Member

    @citystuckhiker

    Locale: Midwest

    > fuel consumption decreased because the stove was running at a slower pace
    Absolutely. Running a stove flat out wastes a whole lot of heat up the side of the pot. Running it at about half power is far more efficient and heats the water almost as fast. I never run my stoves flat out, under any conditions (except for lab stove testing!).

    Here's what I don't get. On the testing, a PR in cold conditions at full flame used less gas to bring 1 qt of water to a boil than a PR in optimal conditions at moderate flame did. Can you explain?

    I assume I would save even more fuel if I operated the stove in cold conditions at a moderate flame.

    I'm going to go test things out tonight in about 10F and report back.

    #1478309
    Tad Englund
    BPL Member

    @bestbuilder

    Locale: Pacific Northwest

    Roger or anybody, has anyone had any experience with a MSR Pocket Rocket using the Brunton Stove Stand?

    #1479447
    Daren Neufeld
    Member

    @darenn

    i took a pocket rocket apart and found that the threads in the bottom of the mixing tube are the same as the threads on the brunton stove stand. i took the jet out of the PR valve and mounted it in the brunton base, and mounted the PR directly on the base. a spacer was required to get the proper hieght. then i got rid of the brunton legs and built a new set out of aluminum. it turned out to be a nice little stove.

    Daren….

    #1479488
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    Hi Daren

    I think I understand, but we want a good photo of it!
    And welcome to the world of MYOG canister stoves. :-)

    Tad – I haven't, but it seems Daren has.

    Cheers

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