stove for winter

[Roger Caffin]

Hi Gary and all

That canister contained maybe 1.6 oz. of fuel, but apparently there was minimal propane left in it. I got no ignition at all.

That would have to be correct. In theory, and it does depend a bit on which approximation you use, standard propane/butane canisters should work down to -22 C (-8 F) or even -24 C (-11 F). However, if the canister has been used upright in the cold the propane fraction will have dropped and the cold temperature limit will not be as low.

I let the flame warm up the stove’s aluminum heat shunt for a full minute, and I then inverted the canister. In another 30-45 seconds the liquid feed took hold, but it was quite erratic. I had to continually adjust the two fuel valves to try to find the right combination to enable a steady flame. I finally found the right setting for the valve at the stove, but the valve at the canister gave me fits. I found the setting where things worked OK for 10 seconds, and then the flame would die. When I opened that valve more fully I got quite a tall flame, but when I turned it down a little it eventually started to die down again.

Your warm-up time is fine, but I think you may have created some of your stability problems by trying to use the valve at the canister to regulate the flame. This is strictly an on/off valve: turn it full on and leave it there. Do all the regulation with the control valve at the stove.

What was happening in your case was that there was some vaporisation at the canister valve because it was not fully open. That meant you had a mix of gas and liquid coming down the hose, so the flame was erratic. The ‘tall flame’ you saw may have been a bit of liquid fuel getting through.

The Winter Stove can work down to the lower limit of the canister, provided the heat exchanger is warmed up and provided the canister on/off valve is opened fully. In real cold I always let a bit of radiation from the stove warm up the canister gently: that helps a lot. Just remember the touch test for safety.

Cheers

 

[Gary Dunckel]

I see now, Roger. I was operating under the assumption that both valves were interchangeable, and that I could use either one to control the flame. I think I formed that habit when playing with the stove in warmer temperatures, and with a custom wind screen. I would need to remove the wind screen in order to access the valve on the stove, which was cumbersome. So I found a nice open position for that valve, about 1/4 turn, and I left it there. Then I could pretty much regulate the gas flow with the valve on the canister. But this didn’t work this morning, probably for the reason you indicated.

I’ll go out right now and practice the proper technique, without using a wind screen. In a couple of days we will “enjoy” yet another frigid morning, and I’ll see how things work when I do it right. I have come to truly love that stove, and I’d like to see what its lower temperature capabilities are.

By the way, did you in fact do that second production run of those stoves? Last spring you were planning for people to send you their stove of choice, and then you would make an inverted setup for it. Did that happen? I haven’t seen any follow-up on it. It would be a real shame if the “Caffin Stove” is no longer available to the public, but I can imagine the work and headaches that go along with making 100 or so of them. You certainly created a work of art with the one you rebuilt for me. I call it my Caffin Gamma Stove, as you used all the tricks you learned during the Beta phase to perfect mine.

It’s now time to go out and play with it.  Thanks for your post, Roger. I think I see how that stove is supposed to be used now.

[Jerry Adams]

have a windscreen that has a gap where the control knob is

strip of aluminum that goes 90% of the way around the stove

[Roger Caffin]

Hi Gary

The stove is designed to have liquid fuel coming down the hose to the stove body and to the heat exchanger there. The control valve regulates the GAS flow. That was a major reason for the design: to avoid trying to control a liquid flow the way every other remote-canister stove does. Liquid to gas expansion is about 1:250, so valving liquid flow without problems of blockage is really hard.

Letting the fuel vaporise at the on/off valve upsets all the thermal dynamics and basically fouls things up. It doesn’t matter in warm weather too much of course, but at 0 F things do need some attention.

It is worth noting that if you keep the canister warm – like in your pack or at the foot of your quilt, then you can in practice run the stove at much lower temperatures: -10 F or -20 F if you must. Just have some thermal feedback to the canister. You may also need some thermal feedback to yourself …

I did see a quite frightening photo of some Norwegian ski tourers using a remote-canister winter stove at a low temperature. They used a long hose and simply stuck the canister on top of the cooking pot! The way they did that suggested that it was common practice for them. OK, but keep the hose away from the flame!

Windscreen – as Jerry said. I use a 3/4 windscreen, with the open 1/4 giving access to the control valve AND allowing some heat from the flames to reach the canister. I orient it all so any wind is from the back of the windscreen and it works fine. Sometimes I use a couple of micro-stakes to hold the windscreen down – that makes it all more stable.

Future supplies of stoves: I hear you. I don’t have any more for sale right now (run out of burners and PFA hose), but I am ‘working on the problem’. I do not want to let the thing just die.

Cheers

[Bob Moulder]

I found some n-butane at the big Korean market — YESSSSS! (H Mart in Hartsdale, NY)

Sold in packages of 4x 8-oz cans for $6.49, so total with tax about $1.75 each, or about 89¢ to refill a 4-oz canister.

Of course it’ll take some time to amortize the cost of that adapter gizmo, which cost about $55! :^0

[Roger Caffin]

Of course it’ll take some time to amortize the cost of that adapter gizmo, which cost about $55!

Is the Return On Investment worth while?

Cheers

 

[Jim Colten]

-10 F or -20 F if you must. Just have some thermal feedback to the canister. You may also need some thermal feedback to yourself …

(snort) … ya think?

It is very hard (or me anyway) to get up, dressed and out at 0F even without being well chilled.  Not a good way to start when I’ll be waiting for breakfast to heat up.  I can get warmed up eventually once on trail but until then …

Maybe I should work on that breakfast in bed thing.

 

[Bob Moulder]

Is the Return On Investment worth while?

I am just so dying to know if n-butane can be used in the winter that I would’ve paid twice that!

Or maybe tried to talk Hikin’ Jim out of his. :^)

But at the rate I was going last year with all the testing it would have paid for itself already.

[Roger Caffin]

Hi Jim

Yeah, cold is cold.

Under anything approaching those conditions I would have a good down duvet with me. So … sit up in bed and put down duvet on over thermal layer. Rearrange quilt or SB over duvet, leaving just an arm or two available. Prepare hot breakfast from depths of downy warmth, by firing up stove at arm’s length. Consume in bed too.

We did consider waiting until the sun hit the tent, but lying there until 10 am is hard …

Cheers

 

[Roger Caffin]

Hi Bob

I am just so dying to know if n-butane can be used in the winter that I would’ve paid twice that!

Eh, well, there are ways and ways.

For 3-season use you could probably get away with iso-butane quite easily. N-butane would require a bit more care, but sleeping with the canister under your quilt should solve many problems.

Doing this in winter … um. For a very mild winter you could use iso-butane with a remote-inverted-canister stove. You might get away with it with an upright and a good well-bonded heat shunt, provided you started off with a warm canister. Out of your pack is one idea for that.

But what about deep winter? Ah well – did you know that in Northern Europe you can buy what look like Coleman Powermax canisters containing 100% propane? Maybe they make the walls just a bit thicker? I believe a few have refilled their canisters with LPG (=propane) without causing explosions, but this is risky unless you keep the canisters in a shed outside at temperatures never going above 0 C. It’s all about the pressure inside the canister, and that is all about the fuel composition AND the fuel temperature. And you don’t keep the canisters over summer either.

Cheers

 

[James Marco]

Yes, you can make most things work if you keep hacking away at the problem. This is what “sleeping with your canister”, “putting in in a dish of liquid water”, “using special heat shunts”, “Heating the canister with a lighter pulled out of a bodily orifice”, etc does. The basic problem is the pressure. It falls off with temperature. At 40F things start to not work as well as they do at 60F. Blended fuels work, but will differentially  favour burning off the more volatile components, so more propane is used than iso-butane than is used for normal butane.

Just because it works in the back yard or on someones patio is not a reason to trust it in the back woods where a no-go can mean the difference between a comfortable trip or one of frigid cold, miserable memories.

Inverted canister stoves are reliable if you have a propane/x-butane mix. I would not tempt the fates with fairly pure n-butane (normal butane.) These are generally from wasted gasses from the refinery and contain a lot of other volatile components none of which are guaranteed to be of a set content. The propane supplies pressure which then burns off evenly in an inverted stove.

WG has more energy for the weight carried. So does diesel. Stoves designed for these fuels are generally much more reliable in cold weather. Carrying the fuel is easy, since you do not worry about pressure except at high (+120F) heats. Pumps can fail, however. Heavier lubing oils can gum up and tear the seals in pumps or simply freeze them in place. Hoses can become stiff and prone to cracking. Or, seals, hoses, and the connections can simply become leaky, as some have alluded to.  Keep all connections freshly oiled with light mineral oil, sewing machine oil, whale oil or the like. In the past I have used my SVEA, an old pumpless stove, down to -25F out ice fishing. This one eliminates the need for a pump, hose and connectors, though it can be hard to start in very cold weather often requiring two/three primes. We also had an old diesel burner that failed on that trip because the fuel we got actually gelled and would not flow to fill it.

Anyway, pressure is the problem, and the danger with canister stoves. Complexity seems to be the problem with WG stoves.

[Roger Caffin]

We also had an old diesel burner that failed on that trip because the fuel we got actually gelled and would not flow to fill it.

Had that happen to our diesel Landcruiser once. Jellied fuel in the filter. It struggled.

Guess how Road service fixed it? A bucket of hot water from a nearby ski lodge poured over the filter! The guy told me to make sure I filled the tank with ‘winter diesel’ next time.

Cheers

 

[Bob Moulder]

What encourages me to try n-butane is how well the system operates in very cold ambient temps at very low fuel levels.

Seems that if straight iso-butane were available that would be the ticket, because that is what essentially remains in a 230g canister with only 17g remaining. And I have run this set-up in fairly windy conditions at +7°F.

The system is reliable. This is the reason that during home testing and field testing I left the stove and fuel in the same spot I used it to cook dinner and simply fired it up in the morning, and I was glad to see Gary replicate this scenario and achieve the same results. I’ve used it enough now that I would not hesitate to take it as my sole snow melting system, although taking along a 25g BRS as a JB back-up is a not much of a weight sacrifice!

So at this point the n-butane exercise is, for me, just icing on the cake and a reason to have more fun with stoves, and to do so with fuel that costs a lot less. I know, Physics and Bernoulli will not be denied. But won’t it be sumpin’ if it works?!! :^)

 

[James Marco]

Roger, Well we had about $10 between us. ‘Corse this was a few years ago, 70? 71? We didn’t know that kero and diesel were NOT the same (truck fuel was a couple pennies cheaper.) -25F was not the time to learn the difference.

[Tipi Walter]

James Marco says

“WG has more energy for the weight carried. So does diesel. Stoves designed for these fuels are generally much more reliable in cold weather. Carrying the fuel is easy, since you do not worry about pressure except at high (+120F) heats. Pumps can fail, however. Heavier lubing oils can gum up and tear the seals in pumps or simply freeze them in place. Hoses can become stiff and prone to cracking. Or, seals, hoses, and the connections can simply become leaky, as some have alluded to.”

It’s funny how this thread got swamped with canister talk but James Marco brings it back to WG for cold weather usage and I concur.  As mentioned I carry an extra new MSR fuel pump assembly on every trip just in case my pump handle snaps or the thing goes south.

The main question I have for canister users is:  Let’s say you’re out in temps consistently around 0F to -10F for several weeks w/o resupply, let’s say 21 days in January—and you want to cook twice a day or maybe more to melt snow.  How many canisters would you need to carry (and empty ones too) to make this trip happen?

[Jerry Adams]

All stoves have potential problems.

I’ve had WG stove clog.  Had to take it apart to clean it.  WG fuel seems like it’s a mixture of stuff that sometimes include impurities.  Especially if it’s old fuel.  (Ignoring the fire balls that occasionally happen).

Maybe alcohol is the most reliable, because it’s so simple.  But it’s so slow and you have to pour liquid for each pot of water to heat up.  Fiddly.

Any stove can fail.  My Coleman F1 developed this problem where when it got really cold, something shrank, and then all the fuel slowly leaked out overnight.  I had a canister fail where the Lindal valve wouldn’t close, but I just left the stove screwed on.

You could do “the Tipi solution” and carry a spare stove and bottle of fuel.  Maybe that would be good if you were far away from safety and it was really cold.

When my F1 failed, I just ate food that didn’t need heating.  Cut trip a little short.  But that was a memorable trip in the sense I figured out how to make do.

For me, canister with “Moulder strip” seems easiest and most reliable.  I never do a trip longer than maybe 5 days so one canister is sufficient so the total weight is comparable to any other stove.

Now, do I do a trip to Olympics where low temp is 31 F or the Rogue River where it’s 26 F?  26 F would just barely be Moulder strip territory.  Hmmm…   Last night they said it would be 22 F, which is better for testing stove but pretty cold for me.

[Gary Dunckel]

Hi Roger,

The thing I don’t quite understand about the 3/4 wind screen is that the stove’s valve is 180 degrees away from the fuel hose. I assume that Jerry hasn’t seen one of these stoves, so here’s a photo of what mine looks like. I made a base for the stove to help stabilize it. It is so light that it can easily try to escape if there’s no pot on it.

So if you set things up such that the valve is on the lee side of the screen, then the hose is on the windward side. I assume that you cut a little opening at the base of the screen to let the hose pass through. This opening would allow wind to get to the stove, right? Also, since the hose comes out on that side of the screen, it doesn’t seem like there’s enough length to then position the canister near the opening on the other side to help warm it. What am I missing here? Could you post a photo of your wind screen arrangement, Roger?

Here’s one of my screen in place, which fully encloses the stove. You can see where the control valve is, and why I would have to remove the screen to access it. This screen is pretty bomb-proof. I designed it so that it would be held in position by the ends of the 3 legs, and moderate wind doesn’t move it around. There’s plenty of air intake holes, and I can position the screen so that no wind can mess with the flame.

The screen allows just enough exhaust space  for my Titan kettle. It is also adjustable such that I can use it with a larger diameter pot, but then it doesn’t contact the ends of the stove legs. In that case I just use small rocks to keep the screen in place.

Since I hate to have to remove the hot screen in order to adjust the stove’s valve, I guess I’ll just need to get it set where I want it and then place the screen. And hope that I got it right.

[Jerry Adams]

Cut a slot in the windscreen where the valve is so you can adjust it.

The hole where the hose goes in isn’t big enough for enough wind to blow in and bother you

I can’t imagine a set-up where you can’t occasionally adjust the valve

[Tipi Walter]

Jerry says,

“You could do “the Tipi solution” and carry a spare stove and bottle of fuel.  Maybe that would be good if you were far away from safety and it was really cold.”

Uh, no way I’d carry a spare stove.  I said stove pump—big difference.  And not a spare fuel bottle—it’s a second bottle to use for the last half of a trip.  I have found in mild winter conditions I can get between 14 and 17 days out of a 22oz bottle of white gas.  At consistent 0Fs it’s more like 8 days per bottle.

[Gary Dunckel]

Jerry, would you mind posting a photo of your remote canister stove and wind screen? I’d like to see exactly how you do it.

[Jerry Adams]

uh oh, a problem with sarcasm is it gets difficult to understand what anyone’s really saying

my 2016 resolution is to not use sarcasm

I use upright.  I assume your request for photo is sarcasm and what you mean is since I don’t have a remote I have nothing worth saying : )

Roger just said that with his remote, you should open up the valve on the canister all the way and use the valve on the stove to adjust the flame.  If there’s a slot in the windscreen you can do that.  I’ve had a similar windscreen to yours and cut a circular hole there, but I’ve seen others where the windscreen doesn’t go all the way around so there’s a slot for adjusting valvle, which seems like maybe a better way

[Gary Dunckel]

No sarcasm was intended toward you, Jerry. Not at all. It’s just that a couple of your posts sounded so definitive that I assumed you did have a remote canister stove, and I wanted to see how you did your screen.

As for me punching a hole in the screen in my photo, you can see that it would be hard to reach the stove’s valve without a needle nose pliers. Or I guess I could replace that valve “handle” with one that is 2-3″ longer. I rather think that the best thing is for me to continue using this stove as I have, but by operating it per Roger’s updated instructions.

[Roger Caffin]

Could you post a photo of your wind screen arrangement, Roger?

Sure:

The hose goes under the edge of the windscreen – no slot or anything. Yes, I am cooking in my tent, and have done so for the last 20+ years. A good low-CO stove, careful priming, and comfort.

The full wrap-around windshields are useful with alky stoves where you need to save every bit of heat, but they are not needed with canister or WG stoves. A wind deflector is highly desirable of course.

Cheers

 

 

[Jerry Adams]

That’s called projection – where I assume everyone else is sarcastic because I am : )

Yeah, Roger’s picture is good

I have just experimented with Moulder strips and have read and thought about inverted stoves

Mostly, my minimum temperature is maybe 28 F or a little colder so regular upright is sufficient

I’m thinking about doing a trip where it will maybe be below 28 F a bit, depending on where I go

[Gary Dunckel]

Thanks for the photo, Roger. I think I’ve seen it before. Since you are in a tent, there shouldn’t be appreciable wind. When you use the term wind deflector, does that mean that you are primarily employing the wind screen to deflect heat back to the pot (and also to the canister)?

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