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Toby Archer checks out a top of the range bag that allies super light technology (hence the "SL" tag) to enough top quality goose down to protect the user from punishingly cold temperatures.Read more at http://www.ukclimbing.com/gear/review.php?id=5328
In reply to UKC Gear:
I wish all UKC Reviews were this informative, comprehensive and well written.
The -15C/-17C area is a bit lacking in bags, I've found. Plenty of good bags on either side but no standouts around that particular spot. Might make a good expedition bag for all but the poles.
I wish all UKC Reviews were this informative, comprehensive and well written.
The -15C/-17C area is a bit lacking in bags, I've found. Plenty of good bags on either side but no standouts around that particular spot. Might make a good expedition bag for all but the poles.
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In reply to Damo: Thanks Damo, it means a lot that someone who knows there stuff like you finds it useful. The Snowline's little brother, the Lightline SL http://www.mountain-equipment.co.uk/the_gear/sleeping_bags/extreme_sl/light... might well hit the mark you mention of about -15.
I was also rather impressed with the Sea2Summit bag I reviewed a couple of winters back which also is good to -15 http://www.ukclimbing.com/gear/review.php?id=3747 Although it's only a 50 grams or so lighter than the Snowline and I remember on one -15 night my thighs were a touch cold by morning (wearing some fleece troos would have sorted that). The thing with the S2S bag is that they have this clever design to make it work better for continuous use, with the synth outer layer.
Unfortunately though I haven't had chance to do multiple nights in a row in either bag - two was the limit - to see whether the S2S construction keeps the bag going for longer. It would be really quite complicated to create "controlled" situations to test that, but if it does work I could see the slight weight increase being justifiable for expedition use.
I was also rather impressed with the Sea2Summit bag I reviewed a couple of winters back which also is good to -15 http://www.ukclimbing.com/gear/review.php?id=3747 Although it's only a 50 grams or so lighter than the Snowline and I remember on one -15 night my thighs were a touch cold by morning (wearing some fleece troos would have sorted that). The thing with the S2S bag is that they have this clever design to make it work better for continuous use, with the synth outer layer.
Unfortunately though I haven't had chance to do multiple nights in a row in either bag - two was the limit - to see whether the S2S construction keeps the bag going for longer. It would be really quite complicated to create "controlled" situations to test that, but if it does work I could see the slight weight increase being justifiable for expedition use.
In reply to TobyA:
The S2S bags look good, but they're expensive and I've never found a place with a few different models all together to compare them in the flesh.
My comment re: "might...expedition bag" was because I find choosing a bag to take on non-antarctic trips one of the hardest gear choices. I used a Rab Premier 900 for many years, which was a great bag. But as a BC bag on the Gasherbrum Glacier at 5000m, supposedly -10/-15C, I got cold several nights over the course of a couple of weeks. But the same bag for a few nights at 5300m on Ausangate a couple of years ago, around -15C, I was fine.
So often on expeditions you are not feeling 100% and have not eaten well, so your body is not generating heat and sleeping like normal. And different locations, though numerically the same (eg. 5000m/-15C) can feel quite different. At Kula Kangri BC, around 4500m(?) in Tibet, I used a $50 KTM fake 'Marmot' bag rated around -5C and felt fine. That same trip I used the Rab 900 at 6200m and bloody froze (-20C?). These places can have such extremes, so hot in the day and then surprisingly cold at night, you feel like an idiot packing a -25C bag on a mule in 30C heat, which you then lay over your tent (the bag, not the mule) at midday at 3500m because it's so hot inside.
Then you have to carry the thing. You know that it might get to -30C at a high camp, but buggered if you're going to carry a polar size bag up that high in a climbing pack. So you want lighter/smaller - but how much smaller? Wear more clothes inside? Hmm, not always great. So you plan to suffer a bit - but how much, and for how long? So a good light bag in this -17Cish range can be useful.
As you say in the review, -20C is serious. Around -5 to -10 maybe you can tough it out for the night if you muck up your bag choice, or just don't care. But at -20 you might not make it through the night, at least not in any shape to go on.
Around -38C things start to get weird, but that's for another time...
The S2S bags look good, but they're expensive and I've never found a place with a few different models all together to compare them in the flesh.
My comment re: "might...expedition bag" was because I find choosing a bag to take on non-antarctic trips one of the hardest gear choices. I used a Rab Premier 900 for many years, which was a great bag. But as a BC bag on the Gasherbrum Glacier at 5000m, supposedly -10/-15C, I got cold several nights over the course of a couple of weeks. But the same bag for a few nights at 5300m on Ausangate a couple of years ago, around -15C, I was fine.
So often on expeditions you are not feeling 100% and have not eaten well, so your body is not generating heat and sleeping like normal. And different locations, though numerically the same (eg. 5000m/-15C) can feel quite different. At Kula Kangri BC, around 4500m(?) in Tibet, I used a $50 KTM fake 'Marmot' bag rated around -5C and felt fine. That same trip I used the Rab 900 at 6200m and bloody froze (-20C?). These places can have such extremes, so hot in the day and then surprisingly cold at night, you feel like an idiot packing a -25C bag on a mule in 30C heat, which you then lay over your tent (the bag, not the mule) at midday at 3500m because it's so hot inside.
Then you have to carry the thing. You know that it might get to -30C at a high camp, but buggered if you're going to carry a polar size bag up that high in a climbing pack. So you want lighter/smaller - but how much smaller? Wear more clothes inside? Hmm, not always great. So you plan to suffer a bit - but how much, and for how long? So a good light bag in this -17Cish range can be useful.
As you say in the review, -20C is serious. Around -5 to -10 maybe you can tough it out for the night if you muck up your bag choice, or just don't care. But at -20 you might not make it through the night, at least not in any shape to go on.
Around -38C things start to get weird, but that's for another time...
In reply to Damo:
Gulp...
I've slept out in temps we've clocked at -27 a few times, for few days in Lyngen where I was using my friend's ME Iceline, which back then (mid-90s) was rated to about -25 I think. It was superb, and shows that ME have been doing this sort of kit for a long time and know their stuff.
The second time was in central Finland in Buffalo 4s inner and outer, which I reckon might have been good to -10 absolute maximum. That was not a great night and I remember it in a lot detail still 15 years or so later! The stupid thing was (in retrospect) that we were essentially car camping, and my Finnish mate had brought his sleeping bag and then just the duvet of his bed to put over that! Not sure why it didn't occur to me to bring more layers.
Was just looking at ME's new website section for the new bag ranges. Their Extreme range looks mental, three models with a good night guarantee for -50, -40, and the lightest ones say -40 too although I suspects that's a typo and it should be -30. The idea of sleeping at -50 seems... well... I can't really imagine what that could be like.
> Around -38C things start to get weird, but that's for another time...
Gulp...
I've slept out in temps we've clocked at -27 a few times, for few days in Lyngen where I was using my friend's ME Iceline, which back then (mid-90s) was rated to about -25 I think. It was superb, and shows that ME have been doing this sort of kit for a long time and know their stuff.
The second time was in central Finland in Buffalo 4s inner and outer, which I reckon might have been good to -10 absolute maximum. That was not a great night and I remember it in a lot detail still 15 years or so later! The stupid thing was (in retrospect) that we were essentially car camping, and my Finnish mate had brought his sleeping bag and then just the duvet of his bed to put over that! Not sure why it didn't occur to me to bring more layers.
Was just looking at ME's new website section for the new bag ranges. Their Extreme range looks mental, three models with a good night guarantee for -50, -40, and the lightest ones say -40 too although I suspects that's a typo and it should be -30. The idea of sleeping at -50 seems... well... I can't really imagine what that could be like.
In reply to UKC Gear:
hey toby, im going to rate this as your best review yet. very dense in the sort of data a review should have, lots of 'surround data' (mats, keeping gear warm etc). quality.
i will differ tho with your comment re double bagging (one down + one synth).
for the weight i think the combo equals or surpasses that of a single at the same warmth and function (even with all the extraneous fabrics and junk that a double system includes).
having been a user of doubles for 4 winters and several expeds (in temps same as you) i will happily qualify 2 bags weighing 550g and 750g each going to -28c. and the outer being a cheaper racing bag (by isuka). have used this same combo now for about 110 nights, and it functions as well in serious cold as it does in humidity (either atmospheric or from steam in a tent).
dont get me wrong, im not trying to poke holes in your review - rather the industry that seems to ignore what many clmbers know and do.
double bags also eliminate the cold patch issue behind the zip baffle, along with a demand for hi-tech (& expensive) baffling methods, and function aross a much larger temp spectrum (a true exped function).
as a sleeping-system-obsessive your review here presents much needed real world data that is usually missed in s/bag reviews (that the likes of damo has got involved shows a standard in its own way).
great to see, and i hope youve stirred up interest in the way bags, insu gear and general stuff gets presented.
just 2 more things:
'yurt' is a russian word of altai origin and considered offensive in central asia/mongolia. pedantic i know, but a big deal thereabouts for ethnic reasons.
and tallisker: good choice.
hey toby, im going to rate this as your best review yet. very dense in the sort of data a review should have, lots of 'surround data' (mats, keeping gear warm etc). quality.
i will differ tho with your comment re double bagging (one down + one synth).
for the weight i think the combo equals or surpasses that of a single at the same warmth and function (even with all the extraneous fabrics and junk that a double system includes).
having been a user of doubles for 4 winters and several expeds (in temps same as you) i will happily qualify 2 bags weighing 550g and 750g each going to -28c. and the outer being a cheaper racing bag (by isuka). have used this same combo now for about 110 nights, and it functions as well in serious cold as it does in humidity (either atmospheric or from steam in a tent).
dont get me wrong, im not trying to poke holes in your review - rather the industry that seems to ignore what many clmbers know and do.
double bags also eliminate the cold patch issue behind the zip baffle, along with a demand for hi-tech (& expensive) baffling methods, and function aross a much larger temp spectrum (a true exped function).
as a sleeping-system-obsessive your review here presents much needed real world data that is usually missed in s/bag reviews (that the likes of damo has got involved shows a standard in its own way).
great to see, and i hope youve stirred up interest in the way bags, insu gear and general stuff gets presented.
just 2 more things:
'yurt' is a russian word of altai origin and considered offensive in central asia/mongolia. pedantic i know, but a big deal thereabouts for ethnic reasons.
and tallisker: good choice.
In reply to ice.solo:
I'm gonna think more about the double bagging thing. I've tried it myself in the past and found fit between the two bags seemed to make a big difference. I guess that comes with trial and error. When I used synth bag over a down bag it worked better than the down bag in another down bag despite the outer down bag supposedly being warmer than the synth one. I think that fit (allowing the inner bag to loft) must be pretty important?
That's very interesting, although wiki suggest it's Turkic in origin http://en.wikipedia.org/wiki/Yurt but got to English via Russian. What do the locals where you have been call their versions?
I should thank my friend Dave http://www.ukclimbing.com/forums/profile.php?id=9833 for taking that photo and even more so for providing the Tallisker!
I'm gonna think more about the double bagging thing. I've tried it myself in the past and found fit between the two bags seemed to make a big difference. I guess that comes with trial and error. When I used synth bag over a down bag it worked better than the down bag in another down bag despite the outer down bag supposedly being warmer than the synth one. I think that fit (allowing the inner bag to loft) must be pretty important?
> 'yurt' is a russian word of altai origin and considered offensive in central asia/mongolia. pedantic i know, but a big deal thereabouts for ethnic reasons.
That's very interesting, although wiki suggest it's Turkic in origin http://en.wikipedia.org/wiki/Yurt but got to English via Russian. What do the locals where you have been call their versions?
> and tallisker: good choice.
I should thank my friend Dave http://www.ukclimbing.com/forums/profile.php?id=9833 for taking that photo and even more so for providing the Tallisker!
In reply to TobyA:
its an interesting concept as it works a bit differently around the condensation/freeze point inside the insulation mass (rather than seting that within the down thats moisture affected, the idea is to set it within the synth thats less so).
the effect is to reduce heat-loss into moisture not just thru convection, so it also helps with moisture from frost/breath (as your review well oints out) and spilled liquids (including tallisker i hear).
over multiple days its noticeably less affected by moisture build up.
to go to town and spend big on the system and get a high-end bag in both categories would be awesome. probably get the weight down to less than 1000g for something that copes to -25c or so. the synth need not be equal to the down - just enough to 'pre-heat' the down enough so moisture condenses/freezes beyond it, rather than within.
this winter ive been messing about alpha as a sleep/active layer (reminds me i gotta email you re a separate matter...), and that pushes it even further towards the -35c standard as alpha doesnt really provide a heat barrier until its trapped by another layer (comple and irrelevant right now).
for sure size matters between the 2 bags, but not so much its a problem unless you try and squeeze a down bag into a super skinny synth. a skinny down inside a regular synth works fine.
in the ultimate system, to then get your mat(s) in between the 2 bags is rollsroyce stuff, and opens up a world of ideas. ive done this with an exped down and 2 zors (on separate occasions). ut room in that concept to start f*cking around with a klymit in winter conds.
jesus, i shouldnt have got started in winter sleep systems....
elsewhere: they are ghers in mongolia, and iyhur amongst the kyrgyz, zhyur for the tajik.
the russian yurt isnt wrong - it just brings up bad memories (the word only means 'home', so its offensive when someone elses word is used for it amongst cultures that own little else and have strict rules about it all.
turkic is from the altai linguistic family (as is finnish).
all variations sound almost identical at first, and all those languages are difficult.
its an interesting concept as it works a bit differently around the condensation/freeze point inside the insulation mass (rather than seting that within the down thats moisture affected, the idea is to set it within the synth thats less so).
the effect is to reduce heat-loss into moisture not just thru convection, so it also helps with moisture from frost/breath (as your review well oints out) and spilled liquids (including tallisker i hear).
over multiple days its noticeably less affected by moisture build up.
to go to town and spend big on the system and get a high-end bag in both categories would be awesome. probably get the weight down to less than 1000g for something that copes to -25c or so. the synth need not be equal to the down - just enough to 'pre-heat' the down enough so moisture condenses/freezes beyond it, rather than within.
this winter ive been messing about alpha as a sleep/active layer (reminds me i gotta email you re a separate matter...), and that pushes it even further towards the -35c standard as alpha doesnt really provide a heat barrier until its trapped by another layer (comple and irrelevant right now).
for sure size matters between the 2 bags, but not so much its a problem unless you try and squeeze a down bag into a super skinny synth. a skinny down inside a regular synth works fine.
in the ultimate system, to then get your mat(s) in between the 2 bags is rollsroyce stuff, and opens up a world of ideas. ive done this with an exped down and 2 zors (on separate occasions). ut room in that concept to start f*cking around with a klymit in winter conds.
jesus, i shouldnt have got started in winter sleep systems....
elsewhere: they are ghers in mongolia, and iyhur amongst the kyrgyz, zhyur for the tajik.
the russian yurt isnt wrong - it just brings up bad memories (the word only means 'home', so its offensive when someone elses word is used for it amongst cultures that own little else and have strict rules about it all.
turkic is from the altai linguistic family (as is finnish).
all variations sound almost identical at first, and all those languages are difficult.
In reply to TobyA:
I have a ME Snowline, bought in 1976 (with my first terms grant as a student) so yes, ME do have a long history. I wonder how the old & new models compare? Back then, the Snowline was 2nd in their range, with the Redline being warmer (& more expensive)
(still have & use the bag, but it given a new lease of life a few years ago
by having the down cleaned & some replaced)
> (In reply to Damo)
> ... and shows that ME have been doing this sort of kit for a long time and know their stuff.
>
>
I have a ME Snowline, bought in 1976 (with my first terms grant as a student) so yes, ME do have a long history. I wonder how the old & new models compare? Back then, the Snowline was 2nd in their range, with the Redline being warmer (& more expensive)
(still have & use the bag, but it given a new lease of life a few years ago
by having the down cleaned & some replaced)
In reply to Doug:
That's pretty impressive Doug, although I actually suspect not so uncommon. I mentioned in previous "eek, that's quite pricey!" sleeping bag review, that the first bag I used when I started doing outdoorsy stuff was my dad's Black of Greenock down bag which I guess was from the early 60s. No zips and made of cotton but still worked OK. Does your one have full zips and the like? Not sure when they started commonly being used. Do you remember how warm it was meant to be when you got it? And how warm do think it is now nearly 40 years on?
After using Buffalo bags through the 90s I got my first down bag in 98 or 99 I think, an ME Lightline. That got used for most nights camping until a couple of years back when I was first asked to review a bag for UK; so only 10 or 11 years - nothing compared to yours - but the Lightline still looks like new and works great. They are expensive when you buy them, but I wonder if there is any other climbing/outdoor gear that people regularly keep using for decade plus? Some of my best boots have lasted something like that but look very well worn after 10 years, whilst I think a well looked after down bag is only just getting going by that point!
> I have a ME Snowline, bought in 1976 (with my first terms grant as a student) so yes, ME do have a long history.
> (still have & use the bag, but it given a new lease of life a few years ago by having the down cleaned & some replaced)
That's pretty impressive Doug, although I actually suspect not so uncommon. I mentioned in previous "eek, that's quite pricey!" sleeping bag review, that the first bag I used when I started doing outdoorsy stuff was my dad's Black of Greenock down bag which I guess was from the early 60s. No zips and made of cotton but still worked OK. Does your one have full zips and the like? Not sure when they started commonly being used. Do you remember how warm it was meant to be when you got it? And how warm do think it is now nearly 40 years on?
After using Buffalo bags through the 90s I got my first down bag in 98 or 99 I think, an ME Lightline. That got used for most nights camping until a couple of years back when I was first asked to review a bag for UK; so only 10 or 11 years - nothing compared to yours - but the Lightline still looks like new and works great. They are expensive when you buy them, but I wonder if there is any other climbing/outdoor gear that people regularly keep using for decade plus? Some of my best boots have lasted something like that but look very well worn after 10 years, whilst I think a well looked after down bag is only just getting going by that point!
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In reply to TobyA: My first 'real' bag was a Blacks Icelandic but by the time I bought mine the quality had started to decline although it was fine except in mid winter.
My Snowline is without zips, etc - so no cold spots but not so great if its warm. No real idea on temperature ratings but the only time I've been cold was a night in the Fords of Avon bothy when it was -20 in Aviemore & I only had a thin karrimat (mistake). We'd also little to eat or drink as the stove wasn't working very well which didn't help.
Other gear bought around that time which I still use at times includes a pair of Salewa crampons & assorted nuts, hexes etc (although the rope on those has been changed a few times) plus a ME Annapurna duvet jacket which is still in good condition - although it seemed expensive at the time
My Snowline is without zips, etc - so no cold spots but not so great if its warm. No real idea on temperature ratings but the only time I've been cold was a night in the Fords of Avon bothy when it was -20 in Aviemore & I only had a thin karrimat (mistake). We'd also little to eat or drink as the stove wasn't working very well which didn't help.
Other gear bought around that time which I still use at times includes a pair of Salewa crampons & assorted nuts, hexes etc (although the rope on those has been changed a few times) plus a ME Annapurna duvet jacket which is still in good condition - although it seemed expensive at the time
In reply to Doug: worth while looking at Peter Hutchinson Designs (PHD) as he was responsible for ME equipment design in the early days.
In reference to double bags, the offer a combi system on some of their bags, so they can be used together.
See their website for further details.
In reference to double bags, the offer a combi system on some of their bags, so they can be used together.
See their website for further details.
In reply to TobyA:
The other thing is that good down bags are usually worth fixing when, inevitably, the first thing goes wrong. That Rab Premier 900 I mentioned above I bought in 1994, made custom from Rab with an extra section added to an XL. The zip went in Anchorage in 2000, after years of sporadic, but hard, use. The shell (heavy DWR Pertex) is still in excellent condition, as is the down. The lining started to thin and fade by 2011, partly from me, partly from often spreading it out to air at high altitude / high UV areas.
It's still useable, but if I replaced or strengthened the lining I reckon there would be another 10 years use in the bag. It's done open bivis in the Karakoram, damp glaciers on the Antarctic Peninsula, and months and months in Nepal. I know that I can go to sleep, wake up with the bag encased in a shell of ice, but not know it because I'm warm and comfortable. I'd like to think Rab still make them like that, but I'm not sure. Most of the 'old' bags (20+yrs) I see in good condition are ME.
> (In reply to Doug)
>
> [...]
>
> [...]
>
> but I wonder if there is any other climbing/outdoor gear that people regularly keep using for decade plus? Some of my best boots have lasted something like that but look very well worn after 10 years, whilst I think a well looked after down bag is only just getting going by that point!
>
> [...]
>
> [...]
>
> but I wonder if there is any other climbing/outdoor gear that people regularly keep using for decade plus? Some of my best boots have lasted something like that but look very well worn after 10 years, whilst I think a well looked after down bag is only just getting going by that point!
The other thing is that good down bags are usually worth fixing when, inevitably, the first thing goes wrong. That Rab Premier 900 I mentioned above I bought in 1994, made custom from Rab with an extra section added to an XL. The zip went in Anchorage in 2000, after years of sporadic, but hard, use. The shell (heavy DWR Pertex) is still in excellent condition, as is the down. The lining started to thin and fade by 2011, partly from me, partly from often spreading it out to air at high altitude / high UV areas.
It's still useable, but if I replaced or strengthened the lining I reckon there would be another 10 years use in the bag. It's done open bivis in the Karakoram, damp glaciers on the Antarctic Peninsula, and months and months in Nepal. I know that I can go to sleep, wake up with the bag encased in a shell of ice, but not know it because I'm warm and comfortable. I'd like to think Rab still make them like that, but I'm not sure. Most of the 'old' bags (20+yrs) I see in good condition are ME.
In reply to UKC Gear: Good review... Would have been interesting to really push yourself (physically) during the day and then try it out. Have you considered VBLs(Vapor Barrier Layer)? This is a simple solution to help with the condensation/ loft of the bag over many nights in cold weather. I have tried with a home made version of nylon and it worked brilliantly and there was no frost and loss of bag loft in the morning. It feels a bit weird to sleep in a VBL and can take some time to get used to.
I would be careful with Tallisker or Alcohol in general... It actually lowers your core temp even though there is a warming sensation... Anyways interesting review! Good one! =)
I would be careful with Tallisker or Alcohol in general... It actually lowers your core temp even though there is a warming sensation... Anyways interesting review! Good one! =)
In reply to Eärendel F.: Am i not right in saying that a vapour barrier liner means you can't dry anything inside your bag while sleeping (i.e socks, inner boots, base layer, etc) because the moisture can't escape through the bag due to the VBL ?
In reply to UKC Gear:
I have a snowline, it's a great bit of kit, excellent quality down and made very well.
I have a snowline, it's a great bit of kit, excellent quality down and made very well.
In reply to Nath93: Well... If you want to dry stuff you could still put it inside your bag but on the outside of the VBL. There will be heat still radiating from your body so it will dry the stuff with a big decrease in the amount of vapor being emitted. I have tried it at a very cold temperature of about -32'C this past winter and it worked great. I was skeptical before but it really worked.
Here is a guy whom did huuuge trips in cold temp lasting many months and used them... here is his webpage.
http://andrewskurka.com/2011/vapor-barrier-liners-theory-application/
Here is a guy whom did huuuge trips in cold temp lasting many months and used them... here is his webpage.
http://andrewskurka.com/2011/vapor-barrier-liners-theory-application/
In reply to Eärendel F.: Fair enough. Interesting article too !
Definitely one of the better reviews, thanks.
Regarding VBLs, is there any point in having one lined with a softer, more comfortable material? Or simply using a thin sleeping bag liner inside it? I'm 99% sold on getting a VBL for my bag because it really suffers after a few nights, but I've got two concerns.
Sleeping in a plastic bag doesn't sound nice, and
I'm worried about all that trapped vapour saturating my thermals.
Should I be worried about those, or should I just get one?
Regarding VBLs, is there any point in having one lined with a softer, more comfortable material? Or simply using a thin sleeping bag liner inside it? I'm 99% sold on getting a VBL for my bag because it really suffers after a few nights, but I've got two concerns.
Sleeping in a plastic bag doesn't sound nice, and
I'm worried about all that trapped vapour saturating my thermals.
Should I be worried about those, or should I just get one?
In reply to ice.solo:
I've been thinking about the same thing as well... alas, the bag was I was planning on using is a bit chewed up by now, perhaps it would be the reason to do it.
Cut open the old Haglöfs Lim +5 (and move the insulation a bit around), then sew it to a closed cell sleeping pad. Have additional down inner bag and another sleepingpad.
But I'm not that fond of sleeping in the cold, so perhaps I'll skip this.
> in the ultimate system, to then get your mat(s) in between the 2 bags is rollsroyce stuff, and opens up a world of ideas. ive done this with an exped down and 2 zors (on separate occasions). ut room in that concept to start f*cking around with a klymit in winter conds.
I've been thinking about the same thing as well... alas, the bag was I was planning on using is a bit chewed up by now, perhaps it would be the reason to do it.
Cut open the old Haglöfs Lim +5 (and move the insulation a bit around), then sew it to a closed cell sleeping pad. Have additional down inner bag and another sleepingpad.
But I'm not that fond of sleeping in the cold, so perhaps I'll skip this.
In reply to UKC Gear: Really good and interesting review, thanks.
A few points:
I’m really glad ME have mentioned that the EN standard is not very reliable at low temperatures – they’re right. The standard itself actually gives no correlation table for comfort limit temperatures below -23.6 °C, and in my experience the manikins used might well be fairly unreliable at temperatures quite a bit warmer than that. It’s nice to see real-life testing backing up the theory – that in your experience ME’s bag is a fair bit warmer than the EN test suggests - though as-ever, giving comfort ratings is a bit of a minefield. Lab-testing of sleeping bags is always going to be difficult, but it's nice when it makes sense.
The amount of technology/ engineering design that goes into all high-spec sleeping bags is ridiculous and I’m glad you highlighted it. When you turn a bag inside-out and see the amount of work that goes into it – yes, even if it’s stitched in China – then you start to realise you’re onto a bit of a bargain. These bags had a lot of R&D pumped into them too, and from a brand-new angle that hopefully improved them a fair bit.
Regarding the double-bagging and Polartec Alpha, this is a really interesting area. 3D spacer fabrics have been around for a fair while (Polartec Alpha’s nothing particularly new as far as I can tell, but it is very well-marketed) but it hasn’t really been used in sleep systems. The huge advantage of 3D spacers is that they provide a massive thermal barrier if the air inside them remains still, but if it’s allowed to move then they give unparalleled breathability. The problem with them is their bulk, but I’d love to see a company make a down bag with a 3D spacer bag sized to go round the outside of it. That'd be interesting from an academic/sad git point of view, but might actually provide a product with real-world uses too.
A few points:
I’m really glad ME have mentioned that the EN standard is not very reliable at low temperatures – they’re right. The standard itself actually gives no correlation table for comfort limit temperatures below -23.6 °C, and in my experience the manikins used might well be fairly unreliable at temperatures quite a bit warmer than that. It’s nice to see real-life testing backing up the theory – that in your experience ME’s bag is a fair bit warmer than the EN test suggests - though as-ever, giving comfort ratings is a bit of a minefield. Lab-testing of sleeping bags is always going to be difficult, but it's nice when it makes sense.
The amount of technology/ engineering design that goes into all high-spec sleeping bags is ridiculous and I’m glad you highlighted it. When you turn a bag inside-out and see the amount of work that goes into it – yes, even if it’s stitched in China – then you start to realise you’re onto a bit of a bargain. These bags had a lot of R&D pumped into them too, and from a brand-new angle that hopefully improved them a fair bit.
Regarding the double-bagging and Polartec Alpha, this is a really interesting area. 3D spacer fabrics have been around for a fair while (Polartec Alpha’s nothing particularly new as far as I can tell, but it is very well-marketed) but it hasn’t really been used in sleep systems. The huge advantage of 3D spacers is that they provide a massive thermal barrier if the air inside them remains still, but if it’s allowed to move then they give unparalleled breathability. The problem with them is their bulk, but I’d love to see a company make a down bag with a 3D spacer bag sized to go round the outside of it. That'd be interesting from an academic/sad git point of view, but might actually provide a product with real-world uses too.
In reply to Mr Fuller:
If I understand you and Sea to Summit correctly, I think that is how their alpine bags work? See the one I linked my review to somewhere above.
> but I’d love to see a company make a down bag with a 3D spacer bag sized to go round the outside of it. That'd be interesting from an academic/sad git point of view, but might actually provide a product with real-world uses too.
If I understand you and Sea to Summit correctly, I think that is how their alpine bags work? See the one I linked my review to somewhere above.
In reply to NottsRich:
I've always avoided it too for the same reason but clearly if you are out for weeks on end they may well have a place.
My friend bought some VB socks before going to Antarctica but said they were a disaster - I think he said you just end up with very very sweaty feet, and his boots without them kept his feet warm enough, but it didn't encourage me towards trying the idea either for sleeping or feet.
I'm currently reading Ray Jardine's ultralight manifesto - "Trail Life" I think the book is called - he mentions VB systems in his "quilt" section but doesn't think they work well, and he has skied to the South Pole amongst other things.
> Sleeping in a plastic bag doesn't sound nice,
I've always avoided it too for the same reason but clearly if you are out for weeks on end they may well have a place.
My friend bought some VB socks before going to Antarctica but said they were a disaster - I think he said you just end up with very very sweaty feet, and his boots without them kept his feet warm enough, but it didn't encourage me towards trying the idea either for sleeping or feet.
I'm currently reading Ray Jardine's ultralight manifesto - "Trail Life" I think the book is called - he mentions VB systems in his "quilt" section but doesn't think they work well, and he has skied to the South Pole amongst other things.
In reply to UKC Gear: I still use my Snowline purchased in around 1974 and its great. It has seen bivvies out in Sarek in the artic circle at minus 30 and in the himalaya at similar silly temperatures. Obviously it was well made !!and apart from losing a little down still in very good condition.
In reply to TobyA: Sea to Summit's website is not very clear, but I think this (http://www.seatosummit.com/sleepingbags/3dnanoshell.php ) shows that their 3D thing is really just a layer of nonwoven very similar to Primaloft, Thinsulate, etc.. It's basically a assortment of fibres stuck randomly together to trap air.
A 3D spacer fabric is a different sort of synthetic which is 3d-knitted to create an ordered fabric. They look like this: http://www.globaltextiles.com/html/images/upload/tradeleads/475/474417.jpg Note the massive thickness and amount of air in the structure compared to something like Primaloft.
A 3D spacer fabric is a different sort of synthetic which is 3d-knitted to create an ordered fabric. They look like this: http://www.globaltextiles.com/html/images/upload/tradeleads/475/474417.jpg Note the massive thickness and amount of air in the structure compared to something like Primaloft.
In reply to Mr Fuller: OK, yes. I wonder when you get to the point of the structures being so open that you get convection currents within the space - in the same way as I can feel cold through my alpkit numo air mattress that I don't feel through a much thinner thermarest?
In reply to TobyA: It depends which literature you look at but I generally go by a 11 mm air space allowing convection to circulate. Below that size its negligible. Radiative heat transfer is another matter altogether, though, and that can occur through these structures relatively easily.
In reply to Mr Fuller: Do you have an idea of what percentage of heat loss is via radiation when were talking of clothing or sleeping bags? I've always figured it was very little as no one seems to bother making silver linings to duvets and the like.
I'm fascinated by the specificity of space needed for convection to become an issue! Thanks. Do you have any simple-ish explanation of why it is so?
I'm fascinated by the specificity of space needed for convection to become an issue! Thanks. Do you have any simple-ish explanation of why it is so?
In reply to TobyA: I agree... I am not sold on VBL clothes at all as then your skin has no chance of ever getting to breath which can lead to foot rot etc. However a VBL inside a sleeping bag is very good if you spend more than one night out. I have noticed that even one night out you can have considerable down collapse. Then the second night is much colder due to the collapsed bag. It does feel a bit uncomfortable to sleep in a VBL but it is def worth it...but good to test it out on your own before you go out in the 'real' world
In reply to TobyA: Radiative effect is very small if the clothing/sleeping bag is thick and there are lots of fibres reflecting the waves all over the place (and potentially back towards the user). Down is absolutely amazing at this and is close to mathematically perfect. If you've lots of air spaces then radiation does become an issue, such as in an airbed (where convection also plays a part). It's unlikely to be much of an issue in winter gear.
Natural convection (ie. no wind etc.) is driven by density effects in the fluid (in this case, air). Turbulence occurs in the space and this circulates the air and transfers the heat. I've got to say, I'm a bit hazy on the details as to why this is... I think (and it is a bit of a guess) that in a small space the boundary layers of still air are sufficiently big that they effectively meet, stopping any turbulence. The maths of it is that there is a number called a Rayleigh number, and below this certain critical value, no convection occurs. In air, the Rayleigh number is approximately 1700. In down assemblies or most fibrous things the Rayleigh number is way lower than this so no convection occurs. However, when you do some fairly unpleasant-looking maths, and the size of the space increases, the measured number rises, eventually becoming greater than the Rayleigh number thus allowing convection to occur.
Natural convection (ie. no wind etc.) is driven by density effects in the fluid (in this case, air). Turbulence occurs in the space and this circulates the air and transfers the heat. I've got to say, I'm a bit hazy on the details as to why this is... I think (and it is a bit of a guess) that in a small space the boundary layers of still air are sufficiently big that they effectively meet, stopping any turbulence. The maths of it is that there is a number called a Rayleigh number, and below this certain critical value, no convection occurs. In air, the Rayleigh number is approximately 1700. In down assemblies or most fibrous things the Rayleigh number is way lower than this so no convection occurs. However, when you do some fairly unpleasant-looking maths, and the size of the space increases, the measured number rises, eventually becoming greater than the Rayleigh number thus allowing convection to occur.
In reply to Mr Fuller: Wow, thanks for this. I had not even considered that something non-reflective (in the common usage of the term, i.e. not silver) would reflect radiative heat, but of course why shouldn't it?
I suspect trying to dig into the Rayleigh number further might severely test my GCSE level physics, even if I did get an A at it!
I suspect trying to dig into the Rayleigh number further might severely test my GCSE level physics, even if I did get an A at it!
In reply to UKC Gear:
sea to summits bags indeed are a layer of primaloft type stuff laid over down. to my mind a good theory, but one that S2S dont apply fully enough - the prima will give a good degree of protection from external moisture, but not enough to make a big enough diference internally as it doesnt quite trap enough air.
prima in a triple layer has a hydrostatic head of about 12,000 (similar to neoshell) so has good effects there, but then becomes a barrier that can allow condensation if the warmth it contains isnt enough to keep the moist air fine enough to pass thru.
i am not convincedthe S"S version has the down-synth ratio right; but then the tests ive been involved with have used primaloft, whereas S2S use something else.
regarding spacer textiles (really to good to see mr fullers points here); alpha is quite different to earlier versions - the hype is mostly deserved if not for concept, then for technology.
earlier versions have been either meshes, high loft piles, 3d meshs as per mr fullers image, or netting with different weaves (something nordic companies have been big on for decades).
alpha tho is a 3d knit that combines a knitted structure with clusters of randomly structured 'fluff' that approximate down and is similar to thermoball (another insulation story for another time).
its very cool stuff in that the weight-thermo efficiency is greater than other knits of the same thickness and far far better than a 3d mesh (that has 2 facing layers).
alpha also has a stretch element.
where this applies to sleeping systems (having done 5 months of tests with different alpha variations) is that alpha is simply efficient at allowing heat transfer from the body to the sleeping bags insulation (which if down, drys it out, and if then covered in a synthetic layer, pushes moisturre out to where its less compromising). primaloft doesnt do this, trapping too much heat against the body. it feels similar at first, but the bag isnt getting enough heat into it to push the mositure away.
its efficient also in that an alpha layer works then well both as an active layer and as a sleeping/static layer; multifunctional. it dries so fast (3 times faster than primaloft) that it sort of works as a wicking fibre.
even better is it doesnt require the sort f fibre-proof fabrics around it that prmaloft and down do, so can be encased in meshes.
dedicated alpha inner bags im not sure are that useful, as simply wearing alpha clothing will work as well. maybe a bag for the lower half, or if its very cold then alpha insulated trousers. alpha breathes well enough as an active garment (tho dependant on whats been used to face it) that garmenst in it have a much greater functioning temp range than prima.
as a part of a super-cold system where alpha garments are being worn a lot of the time anyway, combined with -30c rated s/bags its easy to see the benefits.
all said, prima is still definitely in the game as a moisture limiting textile, and if companies dont optimize on the difference between the two textiles then both will see problems.
sea to summits bags indeed are a layer of primaloft type stuff laid over down. to my mind a good theory, but one that S2S dont apply fully enough - the prima will give a good degree of protection from external moisture, but not enough to make a big enough diference internally as it doesnt quite trap enough air.
prima in a triple layer has a hydrostatic head of about 12,000 (similar to neoshell) so has good effects there, but then becomes a barrier that can allow condensation if the warmth it contains isnt enough to keep the moist air fine enough to pass thru.
i am not convincedthe S"S version has the down-synth ratio right; but then the tests ive been involved with have used primaloft, whereas S2S use something else.
regarding spacer textiles (really to good to see mr fullers points here); alpha is quite different to earlier versions - the hype is mostly deserved if not for concept, then for technology.
earlier versions have been either meshes, high loft piles, 3d meshs as per mr fullers image, or netting with different weaves (something nordic companies have been big on for decades).
alpha tho is a 3d knit that combines a knitted structure with clusters of randomly structured 'fluff' that approximate down and is similar to thermoball (another insulation story for another time).
its very cool stuff in that the weight-thermo efficiency is greater than other knits of the same thickness and far far better than a 3d mesh (that has 2 facing layers).
alpha also has a stretch element.
where this applies to sleeping systems (having done 5 months of tests with different alpha variations) is that alpha is simply efficient at allowing heat transfer from the body to the sleeping bags insulation (which if down, drys it out, and if then covered in a synthetic layer, pushes moisturre out to where its less compromising). primaloft doesnt do this, trapping too much heat against the body. it feels similar at first, but the bag isnt getting enough heat into it to push the mositure away.
its efficient also in that an alpha layer works then well both as an active layer and as a sleeping/static layer; multifunctional. it dries so fast (3 times faster than primaloft) that it sort of works as a wicking fibre.
even better is it doesnt require the sort f fibre-proof fabrics around it that prmaloft and down do, so can be encased in meshes.
dedicated alpha inner bags im not sure are that useful, as simply wearing alpha clothing will work as well. maybe a bag for the lower half, or if its very cold then alpha insulated trousers. alpha breathes well enough as an active garment (tho dependant on whats been used to face it) that garmenst in it have a much greater functioning temp range than prima.
as a part of a super-cold system where alpha garments are being worn a lot of the time anyway, combined with -30c rated s/bags its easy to see the benefits.
all said, prima is still definitely in the game as a moisture limiting textile, and if companies dont optimize on the difference between the two textiles then both will see problems.
In reply to ice.solo: Cool, cheers for that. I haven't seen any Polartec Alpha kit for real yet and probably should do. Reading UKC forums being genuinely useful for my PhD - this is a novelty!
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