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Sleeping bag liners

Posted: Tue Jan 11, 2011 8:48 pm
by quentinc
I have in the past year or so, managed to tear at least 3 silk sleeping bag liners to shreds (a manifestation of my psychological unrest, no doubt). It's wonderful that they are so thin and lightweight, but it's gotten to the point that if I look at one the wrong way, it rips.

Are there liners made out of microfiber, perhaps, that are more durable?

Re: Sleeping bag liners

Posted: Tue Jan 11, 2011 9:17 pm
by rlown
not to appear stupid, but what is the point of a liner? Is there a value beyond the bag i'm missing? I sleep hot so even when it's cold, my bag is generally unzipped. I generally toss and turn, as well.

Re: Sleeping bag liners

Posted: Tue Jan 11, 2011 11:02 pm
by fishmonger
different kind of liner:

http://www.westernmountaineering.com/in ... ntentId=44" onclick="window.open(this.href);return false;

I'm going to try one of these in April - these are mostly supposed to keep the moisture out of the down so there is no ice forming in your bag that you carry around all day after a cold night

Re: Sleeping bag liners

Posted: Tue Jan 11, 2011 11:31 pm
by quentinc
Thanks Fishmonger.

Rlown -- you're lucky to sleep hot. Even though I have a 15 degree bag, I can find myself cold even in the summer in the Sierra. The liner adds at least 5 degrees, is really lightweight, and is really really comfortable. At least until it starts shredding.

Re: Sleeping bag liners

Posted: Wed Jan 12, 2011 10:29 am
by oldranger
Q

As I have gotten older I have gradually slept cooler and cooler. I use a 20 degree WM bag and always sleep in synthetic long underwear. What I bring and wear generally depends on latest weather report before I leave, elevation I will be at, and season. In mid summer I usually just bring a single pair of lightweight bottoms and light silk t-neck top for sleeping. In sept or if the weather is predicted to be cold I bring an extra pair of lightweight bottoms and a shortsleeve t-shirt for sleeping. Late last august when snow and cold was predicted I also packed a 100 wt fleece Hoody. I know the silk liners are light and compact but packing in extra long underwear can serve a dual function of sleepwear plus an extra layer for low daytime temps.

Mike

Re: Sleeping bag liners

Posted: Wed Jan 12, 2011 10:52 am
by Flux
Hey Monger,

from what I understand about that liner is that it's a key piece for extended winter /cold weather camping and does just what you say, keep moisture out of your precious insulation.

Like ranger, I too sleep in thermals no matter what to not only sleep warmer, but also protect the bag. I have a lightweight down sweater I always bring along and usually take an extra pair of bottoms if the weather looks colder and could throw those on before hitting the sack. I get Carpal tunnel from being a computer jockey for work and have found that wearing fleece gloves to bed also increases my comfort and warmth and keeps my hands from getting numb.

I'll say this, skimping on your sleeping warmth for the sake of some weight savings is always a poor choice. Your body burns way more fuel and I know that I sleep like crap and feel drained the next day.

I picked up a Marmot Helium 15 bag this year and it's probably the best money I ever spent on backpacking gear.

Re: Sleeping bag liners

Posted: Wed Jan 12, 2011 2:02 pm
by AlmostThere
I know what a liner is supposed to do, but I always have a dry base layer to sleep in to keep the quilt clean, and take another layer if it's going to be very cold. Since I inevitably end up twisted and strangled by a mummy bag, a liner seems like it would be that much more of a straightjacket.

Re: Sleeping bag liners

Posted: Wed Jan 12, 2011 4:47 pm
by BrianF
Regarding the link in Fishmongers post: I used to use a VBL when I did alot of winter trips. Subjectively I found it added about 5 degrees to my bag (10 with a bivy) and did seem to help with the condensation some, still got alot from my breath around the top tho'. Even when COLD, I think the human body transpires some vapor no matter what, so sleeping in long underwear I would wake up a bit damp and clammy. Still, it did seem to help keep the bag drier after a few days in a cave or igloo. I wouldn't use a VBL myself above about 20 degrees.

Re: Sleeping bag liners

Posted: Wed Jan 12, 2011 10:04 pm
by freestone
It is not necessary to use a bag liner to protect normal body moisture from the down. Down bags are designed to have body moisture "breath" through the bag thus eliminating the clammy feeling. The true enemy of down (indirectly) is body oil and dirt, leading to excessive laundering of the down bag. The advantage of a liner or long underwear is warmth and preventing dirt and oil from accumulating on the nylon. The problem with a liner is that it has very little multifunctional use whereas long underwear is an integral part of the layering system. Happiness for me is putting on a clean pair of merino wool underwear then slipping into a high-loft down bag after a day of fishing or hiking in the high sierra. Ahhhh!

Re: Sleeping bag liners

Posted: Wed Jan 12, 2011 10:35 pm
by fishmonger
freestone wrote:It is not necessary to use a bag liner to protect normal body moisture from the down. Down bags are designed to have body moisture "breath" through the bag thus eliminating the clammy feeling.
I think Western Mountaineering disagrees with you, or they don't design their bags the way you think they should. The clammy feeling is a side effect of the more important task to keep ice out of your down.

I think the VBL mostly matters when it gets down to temperatures when the down near the outside of the bag can cool below 32 degrees, while you're still nice and toasty in the core. This most likely really only affects very warm bags and may not benefit you at all in a 20 degree bag used around 20 degrees.

I plan on a long and cold trip, and am going to buy a bag that is 0 to -20 rated, and I will try the VBL bag, too. In July even at altitude I never had to zip up my +20 REI Halo (which I kept over the Marmot Helium, which I hated for its short zipper that kept me from using it as a blanket), although in late September the 20 degree bag was just barely enough without liner or clothing layers to keep me warm. So when heading out for the winter trip, I won't take chances and go with something that's rated for colder temps that are normal in the area. Once I get a fat bag like that the ice buildup inside the bag will become an issue and since I won't have hours each day to dry out my stuff, I will try my best to keep things dry in the first place.