Oct 26, 2010 at 3:38 pm #1264829
Companion forum thread to:Oct 26, 2010 at 4:05 pm #1658258
@retiredjerryLocale: Oregon and Washington
good article Roger
If you look at figures 3 and 4, towards the end of the life of the canister, the blue and yellow are both good – any n butane is not good for cold weather, iso butane is much better
This is the same as my experience, isobutane is good down to maybe 20 F (or maybe 22 F).
I have been buying Snowpeak "Giga Power" at REI that is a propane/isobutane mixture that has worked good.
Actually, putting in any propane is unnecesary. It helps early in the life of a canister, but towards then end of the life of the canister it makes no difference.Oct 26, 2010 at 4:07 pm #1658260
Excellent article. This will be very helpful.Oct 26, 2010 at 4:17 pm #1658267
Great job! This is the stuff that keeps me here.Oct 26, 2010 at 4:23 pm #1658269
Effin genius …. This should put all cold weather stove arguments to restOct 26, 2010 at 4:24 pm #1658270
the SP Gold lists 85% Iso-butane, not N-butane
maybe their old red can stuff had N-butane in it??????Oct 26, 2010 at 5:04 pm #1658277
@rbeardLocale: ATL, Southern Appalachia
c'mon, not one fart joke? is this not the same backpacking light that published the arm sluice no TP method?Oct 26, 2010 at 5:19 pm #1658283
@knaushouseLocale: Northern California
… since thermodynamics class 30 years ago. Now when I'm on a mountain trail, boiling water on my Snow Peak, trying to keep my can (canister?) warm, I'll think fugacity!Oct 26, 2010 at 5:26 pm #1658286
@biointegraLocale: Puget Sound
Great Article, thank you.
If anyone has any data on other brand fuel mixes to add for reference, this may be a good place:
Brand: Propane / Isobutane / N-butane (country) net/gross weight
Jetboil ?? / ?? / ?? (Korea) 230g/356g
Brunton: 30 / 70 / 0 (Korea) 225g/355g
Optimus: 30 / ?? / ?? (???) ???g/???g
Max Burton: 20 / 60+ / <20 (Korea) 230g/???g
Campinggaz 20 / ?? / ?? (France) 230g/???gOct 26, 2010 at 5:37 pm #1658290
Fascinating article. I'm much further up the learning curve after reading it. Will read it multiple times. Thanks for the spreadsheet.
You add tremendous value to BPL!Oct 26, 2010 at 7:47 pm #1658348
@beaverboymikeLocale: Southern Utah
Every good article has a summary or conclusion section…..for those who don't speak chemistry but want a quick 3 sentence explanation!Oct 27, 2010 at 2:19 am #1658415
> maybe their old red can stuff had N-butane in it??????
I think that is the case.
Obviously, they have seen the light.
CheersOct 27, 2010 at 2:22 am #1658416
> a quick 3 sentence explanation!
Unfortunately, seriously technical things are not that simple.
However, try the paragraph after Figure 4 for a summary, and also the whole section after that for another recommendation.
cheersOct 27, 2010 at 3:28 am #1658420
Roger, can the expansion/boiling at the valve cause the canister temperature to plunge (I have seen mine freeze) taking the actual temperature of the canister well below the ambient temperature? Could this take most canisters (regardless of percentages of each gas) into the no flow zone at -20 degrees C, even when air temperatures are around zero C?Oct 27, 2010 at 4:12 am #1658424
I just sleep with a quart of water (which starts out just below boiling and dwindles to warm by morning) and then use a bit of it in the morning in a 1.5 inch deep bottom of a gallon milk jug (which I use as wash basin, water dipper, and bowl. I set the canister in the water with the stove attached and the gas flows great in freezing temps.Oct 27, 2010 at 7:51 am #1658455
You said ambient air temperature drops about 6.5C per 1000m in elevation gain (per FAA).
that's equivalent to 3.6F per 1000 feet. That sounds about right (if a little high); but doesn't your original height make a difference. E.g. going from 0 to 1000ft versus 11,000 to 12,000ft?
edited per comment below. Thanks.Oct 27, 2010 at 8:14 am #1658464
Actually, I think that 6.5*C/km gained is equivalent to about 4*F/1000ft.Oct 27, 2010 at 9:00 am #1658483
David – yes, the boiling of the liquid gas will cool the canister below the ambient temp. This is explicitly mentioned in the article. This effect gets worse as the canister empties when there is less mass from which to extract heat. At 0C, the cooling effect will be small when the canister is full but will be enough to stop the flow as the canister nears empty for a P/B mixture. P/iso-B may be ok.Oct 27, 2010 at 9:02 am #1658485
> a quick 3 sentence explanation!
Unfortunately, seriously technical things are not that simple.
True that it's not that simple. And I appreciate Roger's and Stuart's explanation of the details. And I've never been accused of being brief. But let me try:
- Stop reading if you will be cooking at temps confortably above 0C (32F) (any fuel will be OK) or below about -40C (which is also -40F) (this article offers no help for that case).
- For temps between -40C (-40F) and -25C (-13F) use 100% propane and accept a substantial weight penalty.
- For temps above -25C (-13F) you can use any of the mixtures that contain both propane and iso-butane with a stove designed to burn canister fuel fed to it as liquid (connected to an inverted canister). Kovea's mix will work down to about -30C with this setup.
- For temps between -10C (+14F) and 0C (32F) you could use MSR IsoPro red canister fuel or Kovea white canister fuel (propane/iso-butane mixtures) with an upright canister.
- Because of evaporative cooling the above suggestions fail if you want to operate the stove for very long in ambient temps near the colder end of the temp ranges. For that case, switch to a setup that handles colder temps or set the fuel canister in a bowl of cool liquid water (at the cost of increased fiddle-factor). This will also extend the temp range of the upright Propane/iso-butane mixtures a few degrees C when the canister is nearing empty.
OK, that's more than three sentences but I think it makes a usable decision tree.
(edited to reflect corrections from Douglas and Roger … I was looking the wrong end of the graphs)Oct 27, 2010 at 9:21 am #1658494
Interesting to note that "back in the day", high altitude Himalayan expeditions favored the old Gaz 206 Bluet stoves. These worked fine in this situation because in spite of the cold (well below freezing) the MUCH increased altitude (lower atmospheric pressure) effectively increased the pressure inside the cannister to the point where the butane would still effectively vaporize.Oct 27, 2010 at 9:51 am #1658510
@smartass-2Locale: Pacific NW
Just wanted to add my voice in saying I thought this was a fantastic article, deciphering and explaining something that affects anyone using a canister stove. I look forward to using this practical information to ensure I don't go without coffee on a cold morning ever again, wondering what the heck is up with my stove and it's full fuel canister.
Thanks for taking the time to research and post this, there is great value in it for me.Oct 27, 2010 at 10:26 am #1658524
Great article! Thanks for the clear details and charts.
>2. For temps between -40C (-40F) and -10C (+14F) use 100% propane and accept a substantial weight penalty.
>3. For temps between -10C (+14F) and 0C (32F) […], or use a stove designed to burn canister fuel fed to it as liquid
Since gas-phase propane provides the majority of the pressure in a canister, liquid-fed stoves can work to temperatures well below +14F. I think the recommendation to use a liquid-fed stove should move from range 3 to range 2. I've used my Coleman Exponent Xtreme at -30C (-25F), although when it's that cold out I pack the canister in snow to keep it warm.Oct 27, 2010 at 10:36 am #1658528
@jorgenLocale: www.smarterbackpacking.com; www.fjaderlatt.se
I have for some years experimented with top-mounted canister stoves in winter here in Sweden. I have found one method that works very well. During the day I ski with the canister in my anorak chest pocket. During the night I put the canister in my sleeping bag. No problem what so ever using the stove at -20–25C (-5F).
It is useful to have a cosy of closed cell foam around the canister as long as the canister itself is warmer than the surroundings. Sounds a bit tricky, but I do not cook for long so the canister seldom gets very cold.
Using a canister stove this way makes it very simple to sit up in your sleeping bag on a really cold morning and cook in your tent.Oct 27, 2010 at 1:16 pm #1658602
> 6.5*C/km gained is equivalent to about 4*F/1000ft
6.5 C = 11.7 F
1000 m = 3,281'
so 6.5 C/1000 m = 11.7 / 3281 = 3.566 F/1000'
That figure is a generalisation of course.
Does the starting altitude have any effect? Not a lot pre se, but I would imagine local conditions will play a far larger part in this.
CheersOct 27, 2010 at 1:27 pm #1658608
Thanks Jim :-)
However, I do not agree with point 2:
> For temps between -40C (-40F) and -10C (+14F) use 100% propane and
> accept a substantial weight penalty.
My reason is that I have cooked below -10 C many times quite happily.
During the day I keep the canister in my pack next to my water bottles, which are close to my back. That means the canister never gets *too* cold, as the water bottles don't freeze. A good use for body heat which should not be ignored.
I always use a liquid-feed stove in winter, and they can run with a canister temperature down to about -24 C. Not strongly, but they can get going. As I usually manage to keep the canister warmer than the environment, this lower limit is not very limiting in practice/
I leave the canister exposed to the flame radiation and maybe sitting in a bowl of cool water – which is above 0 C of course. This means that the canister never gets too cold while in use. If you do this you MUST monitor the canister temperature for safety of course, but that is rarely a problem.
However, if you have a static situation where the canister is at -30 C (eg left behind in an igloo for several days during a cold spell), then you might have a problem. Will Rietveld uses a propane stove for this very successfully.
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