Evaporative Heat Loss in Upright Canisters: Part 2 – Evaluating the Efficacy of Canister Warming Techniques at Temperatures Below Freezing

[Jerry Adams]

Companion forum thread to: Evaporative Heat Loss in Upright Canisters: Part 2 – Evaluating the Efficacy of Canister Warming Techniques at Temperatures Below Freezing

This article tests various canister warming techniques for preserving the efficiency of canister stoves in sub-freezing temperatures.

[Gary Dunckel]

From the good man that first gave us the “Moulder Strip” we now have the “Moulder Trickle Trick!”

When Bob first mentioned it to me I just knew that I would have to try it out. Trouble is that we’ve been having 60-70* F days here in Boulder. So I placed a BRS-3000T stove onto a nearly empty 220 gm canister (~ 20 gm left), and I put it in the freezer overnight. First thing in the morning I took it outside to the far corner of the concrete patio and I had my MYOG Adams Reflector handy, and also a metal disk that would simulate a pot for IR reflecting purposes (my Moulder strip and cozy were tucked away in the basement, and all the handy pots had cozies on them that I didn’t want to burn up). The stove wouldn’t light at all, of course, even with the fuel valve opened all the way. I turned the canister upside down for maybe 5 seconds. I expected that a drop or two of liquid fuel would ‘trickle’ out, but none did. I quickly set the canister upright inside the Adams reflector and used the Bic . It fired right up this time, albeit weakly. After maybe 15-20 seconds the flame gradually became normal (or should I say ‘usable’?). As the Adams Reflector did its canister warming thing the flame became robust, so I turned down the valve to a medium output and went inside to warm up my coffee. I let the stove run to deplete the wee bit of remaining fuel.

So I think that this technique works pretty well, and that it is the second coolest thing I’ve learned on these forums (The Moulder Strip & cozy is my all time favorite).

But I should also mention something about safety here – the young and inexperienced should be VERY careful when trying this out. It is to only be used when there is no other way to get a cold canister to put out vapors. If one has no way to warm up the canister once it is lit, it will quickly cool back down and again be useless. Also, this is strictly to be used in very cold conditions, preferably with snow on the ground (so that any dry forest duff will not be ignited accidently).

Way to go, Bob!

 

[Roger Caffin]

Yes, it could be dangerous, but in reality it is exactly the same thing as ‘squeezing’ a bit of white gas out of a Whisperlite/XGK/Svea by warming the tank, and then lighting the stove. Fireballs R Us.

If you think Bob’s trick is hairy, then so is priming a white gas stove this way. Um … yes, both can be hairy – or maybe hairless? But it is the same thing.

Cheers

[Bob Moulder]

Gary, yours is a very good point that I forgot to emphasize above….

If there is any vapor at all coming out, that alone will be enough to get the thermal feedback loop going with the HX strip. This priming method is to be utilized only in conditions (cold!) when the valve is opened all the way and nothing comes out.

Jerry, I do indeed like the Bic Trick, but the only problem there is that it can quickly deplete the fuel in the Bic. However, even if the Bic is totally exhausted the ‘Trickle Trick’ will still work because all you need is the spark from the flint wheel.

And I’m glad my fellow stovies appreciate the fact that this is no more outlandish (or ‘dangerous’) than priming a Whisperlite or XGK. Due diligence, yes, but it’s not as if you’re lighting a stick of dynamite!

The fun aspect of this for me is appearing to violate the laws of physics with a couple of simple tricks. :^) And the fact that it makes it very easy and quick to start and run a canister stove in very cold weather.

I hope that David Thomas has the opportunity to try this in well below 0°F temps!

[Bob Moulder]

Gary, yours is a good point that I should have emphasized….

If there is any vapor at all coming out while using the HX strip, that alone will be enough to get the thermal feedback loop going and therefore the ‘Trickle Trick” isn’t necessary… it won’t hurt anything, but it will waste a small amount of fuel unnecessarily.

Jerry, using the Bic to warm the canister is quite handy, but that uses up a lot of the butane in a Bic. With the Trickle Trick the stove can still be lit (primed) with flint wheel sparks even if the Bic is out of fuel.

The fun part of this for me is appearing to violate the laws of physics with a couple of simple tricks. ;^)

[Gary Dunckel]

Like I told you, Bob, at first I thought this was going to be another one of those Darwin-esque “Hold my beer, Bubba, y’all ain’t gonna believe this sh*t” techniques. But it isn’t at all. Nope. The good part is that Roger didn’t whap you like we thought he might, so all is well.

[Bob Moulder]

Thanks, Gary, and I’m glad that veteran stovies understand the parallel with priming a WG stove.

But I can also appreciate that folks might get a little nervous when you start talking about inverting a canister to drain some liquid fuel from it and then lighting it.

[David Thomas]

Priming with butane at 0F is like priming with white gas in the summer. Or with propane in a Fairbanks cold snap. Or with asphalt on Venus.

You have a liquid. You want a gas. Burn some liquid to warm the rest of the liquid.

Be aware of the frost-nip hazard of cryogenic liquids.

 

[Bob Moulder]

I just hope there is somebody out there who will try it at -21°F. ;^)

[Roger Caffin]

Eh – Bob is just being logical about it.
But it is not something you recommend to novices who might be tempted to try it at +10 C.

Cheers

[Harry Loong Walker]

We have made a fleece jacket for the canister. That works fine it is not to cold.

If it is very cold I put a hand warmer underneath. One that is liquid and has a “coin” that I click on, so it releases heat and became solid. Theoretically it could create heat that is on the edge as the canister is design for, but since it is cold outside the temperature never gets close to that heat.  In this way the burner gets both gases in correct amount to burn efficient.

We only makes day trips during winter time. It might not be as convenient for overnight trips, since you might need to reheat the hand warmer by boiling them in water as both takes time and fuel.

[Ken Thompson]

Thanks Jerry. Looking forward to the rest of the series.

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