stove for winter

“But I assume that it would be quite suitable for my ex-wife, with no instruction whatsoever?”

Well depending on how much you care about her, you may or may not want to add tip #3 to Bob’s two tips:

“Make sure you engage the wire lock at the end of the insertion tube before you start pumping while the stove is lit so that the tube does not pop out, spraying liquid flames all over the campsite and your ex-wife.”

Bob says: “I have heaps of experience with MSR WG stoves. If I could pass on one tip it would be to make certain to lubricate the end of the fuel tube, with oil, spit or nose grease, before inserting it into the pump, because if you scuff that o-ring you’re screwed, especially when it’s very cold… as anyone familiar with the “Challenger” disaster knows. And oil the pump cup. OK that’s 2 tips.”

I agree and always carry a little tube of MSR pump cup oil, plus I regularly replace that little O-ring.  On my long winter trips I even carry a complete and new spare stove pump in the top lid of my pack.

Hi Ralph

Yes, I do still have a couple for sale. email me.

roger@backpackinglight.com

The Primus specialty “season” canisters are impossible to find in the USA. I found some Primus Summer blend (25% isobutane, 50% n-butane, 25% propane) at a German site called eXXpozed and hope to test my theory that the blend does not matter when used with my copper strip setup. I got 5 230g canisters and with shipping they ended up costing $8.50 USD each.

I have been thinking about testing with pure n-butane. Any ideas about how I could obtain this? Or how to transfer n-butane to a standard blended-fuel canister??

It’d be interesting if pure n-butane would work because that would mean much lower canister pressures and potentially much lighter canisters.

All we need now is winter… forecast here is for 73°F Christmas Eve!

n-butane more commonly used for cooking, maybe look at a cooking store?

a couple years ago there was a thread(s) about filling from one canister to another.  You have to buy some adapter(s), like from Ebay.  One trick is to warm up the canister you want to go from, and cool down the canister you want to transfer to (like in the freezer), attach adaptors and have the canister you want to go from on top.

Make sure you weigh the canister and don’t over-fill or it can rupture when it warms

the weight of the canister is of the liquid, all the different butanes and propanes would be pretty much the same

OK, thanks, I’ll look for that adapter.

I googled:

http://backpackinglight.com/forums/topic/58375/

Perfect!

Thanks much for finding it for me. :^)

Yesterday I found more of the Nabisco cookie cups, but with clear plastic lids! This lets me see what is stored in the concavity of the canister. In this case, it’s a mini Bic and 1.5 four-gram Esbit tabs, vacuum sealed for use as an emergency fire starter.

Besides keeping the Bic (or whatever) waterproof because of the tight seal, the plastic lid also prevents the canister from scratching the bottom of the pot when you are bouncing down a scree field. On the right you see a 2 oz. Nalgene bottle, which holds a bit more water than needed to fill up the concavity of the canister. This bottle would be kept in a pocket inside your parka close to your body to keep it close to 98.6* F until time to use it.

The lid is not a bad multiple-use item, all in all–and it’s just 4 grams!

In the interest of combining threads (when I gave you a heads-up about REI’s sales prices on a couple of items), I show how the Evernew 400 ti cup nicely replaces the stupid stock plastic bottom cup of the Sol (note that I swapped out the plastic handle covers with heat resistant silicone tubing). This cup allows you to actually cook or simmer something like soup, at just a .75 oz. penalty over the stock 1.0 oz. bottom cup. Also, Josh’s #2 CF lid works for both the Sol and this cup. It doesn’t completely slip over the pot like the stock one does, which leaves some room inside for something like a microfiber wash cloth. The BRS-3000T stove fits inside the fins, being kept in place by my riser disk thingy. The entire kit slips into a custom cuben drawstring bag to keep everything together during transit, or to keep snowflakes at bay during the night.

I know, I know…too much information, and certainly a bit of thread drift. But I wanted to tell you about the clear cookie lids–muchly more betterer than yellow…

That’s a really well-thought-out winter kit, Gary. Very cool that Josh’s CF lid fits the Sol and the Evernew cup, and a good idea to replace the stock one with something truly useful.

I also like it when the entire kit fits into a stuff sack. Neat! You’d never know it from looking at my desk, but, at least in regards to backpacking, I’m of the “a place for everything, and everything in its place” persuasion. :^)

Thanks, Bob. You should also know that my 1.125″ copper strip and the velcro/carbon felt strip also nest inside the pot as well, so this whole kit is pretty complete and concise. It won’t work for much snow melting, but it is fine for otherwise cold weather boiling and soup simmering. Another thing about that EN cup–the canister nests nicely inside it, which will allow me to pour some warm water into it and thereby warm the canister (probably best done without the lid on it, to allow the warm water to more fully contact the canister).

By the way, Bob, I’m thinking that a .021″ thick copper strip that is 1.0-1.125″ wide is more efficient than my .75″ width strips. After several cold temp tests, the wider ones seemed to work better after all. More geekiness to be continued regarding all of this…

I like my Trail Designs Sidewinder Caldera Cone in the Inferno wood fired mode. The only fuel I have to carry is a few ESBIT tabs for fire starters. The rest of the fuel is in the woods.

Otherwise I’ll use the white gas version of my MSR Whisperlite Universal for seriously sub zero trips.

>>>By the way, Bob, I’m thinking that a .021″ thick copper strip that is 1.0-1.125″ wide is more efficient than my .75″ width strips. After several cold temp tests, the wider ones seemed to work better after all. More geekiness to be continued regarding all of this…

Gary, it might very well be that you’re reaching the point where a canister cozy is beneficial.

When the fuel level in the canister is low and the ambient temperature is low enough, the system begins to give up heat to the environment and performance diminishes somewhat. I noticed this first when doing some testing last winter with the 230g canisters at +7°F. The EVA cozy totally resolved this issue, so it might be that the width of the strip (within reason) is less important than preserving more of the heat shunted to the canister.

I’m glad you are able to continue your testing because I can’t do much here. It got up to a very un-Christmas-y 74°F here yesterday and I’m fearing this might be the year with no winter for us.

I’m quite content with the current system as it is. The only thing I want to explore further is whether it will operate using the “summer” gas… or n-butane only, which would be a huge and very pleasant surprise.

I’m SO happy I kept some copper sheeting I used to line my machete sheaths. Now I’ll make two of those “Moulder strips” and make some Velcro straps.

Very clever Robert, very clever. Does your wife know you are this smart? (They usually don’t ;o)

Alrighty, then. Bob thought I should have a cozy, so I made this out of 3/16″ carbon felt (and duct tape). It’s a simple ring that I can slip onto the canister, and a separate felt disk to be the base insulator.

In the interest in again combining concepts, the next photo shows the cozy, an EN 400 cup, a cookie cup lid (this time with perforations), and a hand warmer. Can you see where I’m going with this?

The hand warmer fits nicely in the canister’s bottom concavity with the lid placed. The felt base will sit inside the cup.

Since the hand warmer needs a minimal bit of oxygen to function, I thought that the carbon felt would offer that, whereas closed cell foam wouldn’t. The felt also is a good insulator, and so is titanium, to some degree. Here’s the assembled setup:

This arrangement also allows the use of a copper heat shunt strip to be placed between the canister and the felt, and to not bother with the hand warmer. It is a snug fit, and Velcro is not needed to keep the copper strip securely in place.

When I was first testing the hand warmer/cozy setup, I wanted to monitor the effectiveness of my idea, and see if the carbon felt was breathable enough to keep the hand warmer working. I have a fairly accurate mini thermometer from a hack job of one of those REI compass/thermometer zipper pull gizmos. This sits under the canister on the felt base.

I found that the hand warmer consistently raised the temperature of the canister by ~ 20 degrees F greater than ambient, whether it was done in my living room or outside in 35* F to 50* F air. While these hand warmers are rated to 135* F (average), they had expired in Aug 1014, so they probably are less effective now. The maximum temperature that my little thermometer showed was 85* F while being used in my 67* F living room. Certainly not dangerous at all.

Now, boys and girls, here’s what I did at 6:00 AM this morning. The forecast was for last night’s low to be between 6 and 8 degrees F. It was 8* F on my patio. I had set up my canister stoves last night before I went to bed, and everything sat there all night, getting nice and chilly. I purposely used canisters that had less than one ounce of fuel remaining. The three canisters had 1.0 oz., 0.5 oz., and one had just 6 grams of fuel left.

Here are the results:

First, I placed a fresh hand warmer under the canister that contained 0.5 oz. of fuel. This was used with the carbon fiber cozy and EN cup, and a Snow Peak Giga stove was used. I let this setup sit for 15-20 minutes to let the hand warmer do its thing.

While I waited, I placed warm tap water into the concavity of the Optimus canister that contained just 6 grams of fuel. I used a Coleman F-1 Ultralight stove for this one. I waited maybe 30 seconds for the water to warm the canister, and the stove fired right up. It continued to run for 10 minutes at medium flame, when it ran out of fuel. The warm water trick seemed to work fine. The weak link would be that the water would have to be replaced frequently if a lot of water needed to be boiled.

Then I turned my attention to the hand warmer/cozy setup. I used the MSR canister containing 0.5 oz. of fuel and a Snow Peak Giga stove. I quickly checked the temperature inside the cozy, and it showed 35* F (ambient was still 8* F)–a 27 degree rise in warmth, and the canister was certainly warm enough to function fine. After 15 minutes at a medium flame setting, the stove’s output began to decline. I expect that the fuel was just about used up. I have confidence that this arrangement would likely work fine, especially if one used a fresh canister. The hand warmers seem to work pretty well for 6-7 hours, and these are expired ones. The weak link with this approach is that one must take along extra hand warmers (at ~25 g each time you want to use the stove).

Now for the copper strip heat shunt, using a BRS-3000T burner. The canister had a whopping 1.0 oz. of fuel left, and I was figuring some of that was propane. The stove lit right up, but it was a pretty weak flame. Within 30 seconds the copper shunt did its work, and the flame behaved as it should. At this point I shut the stove off and I took the canister/stove inside to quickly weigh it. Then I fired it back up and set my JB modified Sol with 2 cups of very cold water on the stove (the Sol was left out overnight, and I poured 45* F water into it). The BRS-3000T was set at a moderate flame setting. It reached a full boil in 5:30 minutes, and it used 5.3 grams of fuel to do so. This, to me, was rather remarkable.

So from this limited experiment, I am convinced that the best arrangement (for me) will be the combination of the carbon felt cozy (13.2 grams) and a copper strip (16.2 grams). For 29.4 g (1.037 oz.), this would be a pretty effective way to warm up a canister in temperatures I hope to not be camping in very often. And, as a true belt-and-braces approach, one could also bring along a cookie cup perforated lid and an extra hand warmer to truly bump up the firepower in frigid conditions (like -25* F?). However, I would strongly suggest that the hand warmer be removed before employing the copper heat shunt. I have no idea how much canister heat that combination might create (Roger, have I scared you yet?).

Thanks again, Bob, for introducing me to this concept. I love the collective knowledge base we have here on BPL.

Hi Gary

Roger, have I scared you yet?

Not in the least, for two reasons:

1. Your combo is working fine and is not getting anywhere near a dangerous level of temperature (ie over 50 C).
2. You are in USA while I am in Oz. I figure I am well outside any likely blast radius … :-)

My compliments about the serious testing and measurement you have been doing. Miles better than the stuff one gets in other mags, like “and I managed to boil a cup of water”.

Cheers

Gary,

Wow-wow-wow! Thanks for all the effort you’ve put into testing and comparing with other techniques!

No need to worry about overheating, and I can tell you why: This past summer I wanted to test the ‘idiotproofness’ of the arrangement, and did so by using the HX strip PLUS cozy with ambient temperatures of 75-80°F, stove burners (MiniMo and BRS) set to max, burning for more than 1/2 hour. Got way warmer than necessary, of course, but nowhere near 150°F (105-111°F, monitored closely with digital thermometer probe). There was in fact some very minor melting of the MiniMo pot support where the strip passes through, but it’ll never receive abuse like that again so it will be fine for the long term when used as intended.

Thanks very much, Roger. As for you and Sue being safe from my patio experiments, I was thinking of renting a small place just east of Wilberforce. That might put you right in harm’s way of my follies, right?

“Hide the children and small pets! That Dunckel kid is playing with matches again!”

Happy new year, Roger.

Thanks, Bob. Your summer testing is very comforting. Roger’s 50* C is  our 122* F (not 150* F), and you were under that. I think that we’re getting somewhere with this winter stove testing. Heck, you’ve even got Ralph and Eric jumping into our game. Maybe it’s the cookies…?

I’m hoping that we can get another 0 degree F spell here, so that I can do my lower-temp test of Roger’s superb inverted canister stove. I did it last year when it was +10* F and it worked great, but I still want to see how it performs at 0 degrees or colder.

Happy New Year to you, Bob.

Gary:  Thanks for the well run tests and detailed writeup.

Just one comment about  “The weak link with this approach is that one must take along extra hand warmers (at ~25 g each time you want to use the stove).”

As you mentioned, the warmers require oxygen to work.  A friend who has to deal with Reynauds disease/<span class=”st”>phenomenon</span>/syndrome uses mitts designed for use with hand warmers and shuts down partially used warmers between uses by storing them in a freezer bag with most of the air expelled.  He stores the bag in a freezer … I do not know if that is required.

That’s interesting, Jim. Maybe if I’m just at home, I could vacuum seal a partially used hand or body warmer. I think I’ll  try that, and let them sit unrefrigerated for a couple of months. It will tell me if those FoodSaver bags are truly air-impermeable. If the hand warmer doesn’t return to function, I’ll know that air gets into the bags. If they actually keep all air out then they would keep all odors in, and they would likely eliminate food smells when in bear country.

Thanks for posting that, Jim. Now you’ve set me up with yet another geek experiment to help get me through the winter.

Follow up post here. I woke up at 5:30 this morning to a muy frio house (60* F inside!). My atomic clock registered a patio temp of +6* F, colder than yesterday. I really wanted to slip back into my heated water bed (yes, I still sleep in one of those), but it was perfect for another early morning round of canister stove testing. I didn’t think it would be this cold, so I didn’t put the canisters and stove outside to get chilly. I put on my merino base layers and fleece top and bottom, put the stoves outside, turned on a space heater, and got close and personal with my coffee cup. After an hour there was enough light to see what I was doing outside, and I figures the canisters were close to ambient temperature, which was still +6* F.

I used an MSR that had .8 oz of fuel left from yesterday, and it was combined with a BRS-3000T burner, the felt cozy in the EN 400 cup, and also a 1.125″ wide copper shunt strip (no hand warmer was involved). I was mildly surprised that it fired right up, but with a rather weenie flame. There must have been a bit of propane remaining. Within 30 seconds, the flame became fairly robust but not maximum. Plenty of flame to boil water though, although I chose to not do that this morning. It chugged along well for 20 minutes until it ran out of fuel. This confirmed my feeling that the copper strip and cozy is all that is needed to make a canister stove work in temperatures below +10* F.

Then I switched my efforts to see how my Caffin stove would work at +6* F. I used partial canisters of Camping Gaz fuel. My first attempt to start the stove in upright mode to warm the heat shunt was a miserable failure. That canister contained maybe 1.6 oz. of fuel, but apparently there was minimal propane left in it. I got no ignition at all. I then switched over to a Camping Gaz canister that had 5 oz. of fuel remaining. I only let it chill outside for 15 minutes, so the stove fired right up. 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. I got grumpy, and I decided (rightly or wrongly) that this stove isn’t meant to be used at + 6* F. I am thinking that it would work OK at +10* F (as I learned last winter), but maybe not anything below that. I feel that I found the lower temperature limit of that beautiful stove. So I quit testing and went inside to warm up and have breakfast.

One last thing. Last night I opened a hand warmer and let it get to “operating temperature.” I then vacuum sealed it in a FoodSaver bag. It cooled down fairly quickly, due to lack of oxygen. My idea last night was to put it on the shelf in the basement pantry and check it again in a few  months. This morning I got curious, so I opened the bag and placed the hand warmer in my shirt pocket to see it still worked. It did, by golly, and it’s nice and warm. I’ll vacuum seal it again now, and we’ll see how it does in another week or so. That’s a great tip about removing the air to stop the heating process and reuse hand warmers. Thanks for that, Jim.

OK, I’m done. That is, until Bob Moulder comes up with yet another way to tweak these canister stoves for cold weather use. For now, I’ll teach myself how to remove and replace trekking pole straps. Then I want to figure out the optimal tab-to-pot distance for the Coglan’s 7 gm. fuel tabs (it seems to be a bit different than that for Esbit tabs).

Have a great week folks. Go Broncos tonight!

My butane bits — filler adapter and “summer” canisters — are on slow boats from Japan and Germany, so it might be a while. :^)

I thought I had found an online source for the 8-oz butane cans for tabletop stoves, but although the price came out to $1.29 per can, the shipping for a case of 12 was $141.00!! Anyway, there’s a huge Korean market not too far away so I’m going to check that (because they love those tabletop bulgogi grills!), and also look for a local restaurant supply store that might have them.

>>>This confirmed my feeling that the copper strip and cozy is all that is needed to make a canister stove work in temperatures below +10* F.

I’m impressed that your setup works as well as it does without the velcro strap holding the strip tightly to the can. I hope it does get cold enough that you can check whether it still works well in your current configuration at -25°F, or if perhaps the velcro strap is beneficial when it gets that cold.

I’m anxious to hear about your testing because I sure as heck can’t test here! Maybe it’ll be somewhat cold by the time I’m ready to test the butane.

That’s a really good test – mostly empty canister, just operating at a particular temperature, thanks

The tests where you put it in freezer to cool down, or in a water bath with ice cubes are difficult to interpret, not very useful

I’m impressed it works so well at such a low temperature

If there was a velcro strip, maybe copper would make better thermal contact to canister and work a little better, but it works as is so…

Actually, Bob (and Jerry), the copper strip is snugly in full contact with the side and top of the canister. The cup’s ID and the thickness of the 3/16″ carbon felt are exactly right to leave just barely enough room for me to slip the .021″ thick copper strip in place. If any of those dimensions was 1/2 a mm different, this wouldn’t work quite as well as it does.

I would love to find a source of 8 oz. 100%  butane canisters for use in these tests as well. That would be the litmus test for our purposes. Let us know how you do at that big Korean store. If they are that cheap, they would certainly work great for most summer uses, as well as for our tests. I go through a lot of canister fuel for my various tests, and I find the cheapest 4 oz. canisters around here are the Optimus brand at $4 each. I can’t find their 8 oz. cans anywhere. My preferred brands for actual field use are MSR and Snow Peak. While Jetboil might be a superior fuel due to the 25% propane content, I can’t justify paying the same price for 10% less fuel. It’s funny, but JB actually puts a few more grams of their fuel in the 220 gm. canisters than SP and MSR does. I expect that they might use a slightly more stout canister for the larger size, but they use the same 4 oz. canister as the others. I guess they feel that the extra partial pressure of their 25% propane requires that they put 10% less fuel in that canister. When I can’t find anything to buy at REI with my 20% coupon, I’ll pick up an 8 oz. Jetboil canister. That’s the only time I buy that brand.