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chrisb
Dec 9, 2006, 4:39 PM
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Apologies in advance, hardened alpine folk.
So, when using a VBL in down bag (over multiple days), how do you dry out gloves and such? Between VBL and bag? Not inside the bag, right? Hire an elf to toast them over a fire?
Subquestion: what do you do with your sleepwear that, after a night in the VBL/bag, is now essentially soaked?
Thanks,
cb
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dalfollo
Dec 9, 2006, 5:03 PM
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Aren't VBLs so....20th century?
put the gloves between the VBL and the sleeping bag.
I do not use a VBL as there are other ways to deal with the issues and i really don't like the idea of sleeping damp when it is cold.
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dan2see
Dec 9, 2006, 5:41 PM
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A VBL is a Vapour Barrier Liner for your sleeping bag.
Here's an on-line example:
Western Mountaineering "Hot Sac VBL"
http://www.backcountrygear.com/...TS__PRODUCTID=WE5100
I always line my sleeping bag with a plain bed-sheet. That gives me a cozy feeling, and keeps the bag's inside clean.
When I sleep on snow or damp ground, I always add a blanket under my bag, for even more cozy dryness.
I have never had to bivouac on a mountain, but if I was planning this, I'd rather haul up a bivy bag.
(This post was edited by dan2see on Dec 9, 2006, 6:03 PM)
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chrisb
Dec 10, 2006, 2:40 PM
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dalfollo wrote: Aren't VBLs so....20th century? put the gloves between the VBL and the sleeping bag. I do not use a VBL as there are other ways to deal with the issues and i really don't like the idea of sleeping damp when it is cold.
Thanks.
What are the 'other ways' of which you speak? I agree--damp is bad in cold. But I'm a super sweaty guy (especially at night, regardless of season/conditions) and worry about wetting out my down by the third/fourth night.
Thanks again.
cb
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Masterblaster
Dec 11, 2006, 6:33 AM
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I have never used a VBL for my sleeping bag in the mountains and wonder why you would want to. If you are sweaty anyway, this would only exacerbate the problem. If I were you I would wear a thin layer of poly pro inside your bag and if you are sweating, unzip it!
On long winter exps or high altitude climbs my bag becomes my oven and drying chamber. Boot liners, gloves, batteries, contact solution, and my gameboy all go inside to either dry out or keep from freezing.
Always keep a dry pair of socks in your bag to change into when you crawl in. Tuck the socks you wore that day between your thighs and your long underwear. Put your damp gloves on your chest / core above one layer of polypro and another shirt. Do not try and dry too much at once b/c it will make you really cold.
Change out of your sleeping socks in the morning and put on your now dry ones from the day before. Keep your sleeping socks in the bottom of your bag. Vent your bag in the morning either in your tent or if it is sunny in the am, lay it out in the sun or on your tent to help dry it. If it is butt-cold you can take it outside, let all the misture freeze and scrape off the ice with a brush. I have found that you can squeeze a few extra days out of a bag if you dry it in the morning or take advantage of sunny hot tiimes during the day to take your bag out and dry it in the sun.
I have never used a down bag on a long winter or high altitude trip, even at -30 and 19,000 feet. Maybe if you sweat that much, you should get a synthetic bag. SOmetimes if tit is real cold or i am bivying or in a megamid i will use a bibler bivy sack to stay warmer. Remember to scrape the ice off of the outside of your sleeping bag after it freezes once you get out of it in the morning.
Happy camping!
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zxcv
Dec 11, 2006, 6:41 AM
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I am not terribly experienced in this area, but this is what I have been doing.
I wear either a micro-weight wool baselayer (top and bottom) or a real thin synthetic (havent decided which I like better yet) that I never change (for up to 4 days). When I get to camp, I immediatly put on a synthetic belay jacket, take off anything wet (gloves, hat) and put the items in the inside pockets of the jacket to dry while I use a dedicated pair of camp gloves to set up the tent, cook, etc. My body heat begins to dry the stuff
When I sleep (down bag), I quickly strip down to the baselayers, put on VBL clothing including socks and put my belay jacket back on. There is always a bit of moisture in the jacket, but nothing compared to what I sweat off at night and hopefully by bedtime the gloves/hat/etc in the inside pockets have dried a bit.
When I get up, I reverse the process- take of jacket, take off VBL stuff, put jacket back on...
This is my best shot at keeping my down bag dry while attempting to dry stuff out. It works to a degree, but can be a real hassle. I am tempted to just get a synthetic bag and not mess with the VBL at all.
(This post was edited by zxcv on Dec 11, 2006, 6:42 AM)
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pastprime
Dec 13, 2006, 6:08 PM
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I have used vbl a lot on extended winter trips, and wouldn't want to be without it. Some like it, some don't, but as in most things, I'd not weigh too heavily the opinions of those who haven't tried it in the conditions where it is beneficial.
Benefits are, it adds a solid 10-15 degrees of warmth for only a few ounces; it keeps the down dry from the moisture your body gives off during the night, which accumulates day after day if you get up and go in the am without having time to loiter around camp waiting for the bags to air; and, not a minor point, it saves about a pint of moisture that your body will give off to keep the air near your skin humid, no matter how cold you feel. (it is stopping the cooling from that insensible perspiration that makes the vbl warmer). This saves fuel and time from melting that much more water.
If you are actually sweating during the night, you are too hot. Open up the bag. I've never- that is never- been soggy in a vbl; though I commonly pump the air in and out of the bag a couple of times a night if the air feels too humid. It becomes automatic after a while and I hardly wake up to do it, it's like turning over in your sleep.
I always just take the wet stuff inside the vble with me. You don't want the water getting in the insulation. I get in the bag right away in camp to save heat, keeping at least my legs and hips in the bag while cooking, eating, melting water, fiddling with gear and so on. The stuff is usually well on the way to dry by the time I'm ready to sleep. The closer it is to your skin, the faster it will dry. Keep pumping the air now and then to keep the humidity in the bag low enough that the stuff is drying.
I have commonly been on trips where the others bags were getting soggier every day, to the point of danger, while my system was pretty dry; as dry as if it were home in the closet, when I used a thin synthetic insulated overbag.
(This post was edited by pastprime on Dec 14, 2006, 4:47 PM)
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dalfollo
Dec 15, 2006, 2:54 AM
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pastprime wrote: ...it saves about a pint of moisture that your body will give off to keep the air near your skin humid.......This saves fuel and time from melting that much more water.
Are you joking?? The body does not regulate the humidity around your skin...if it did, we would never need Goretex, and every winter jacket would be a VBL....about the venting part...I thought you were saving water and heat by using a VBL...seems you are losing it with the venting...
a couple points that work for MY sleeping comfort, and pointers for doing without VBLs...
- when you get to camp take some time to bring your HR down and dry to some degree in the clothes of the day
- start the drying process of putting gloves inside your pile...you are trying to dry so you don't jump from "wet" day clothes into night "dry" polys
- when you head into bed plan to switch into fresh polys or silk with fresh liner socks (if not full socks)
- in cold climes plan on a liner or heavier (dry) balaclava...you have a lot of blood vessels close to the surface in the head and neck, easy place for heat loss
- NEVER, NEVER go to bed in the same clothes from the day...
- as mentioned above if you are sweating your bag needs venting or you need a lighter bag
- I have found that down does a much better job of venting vapor than does synthetic fiber
- if your feet seat too much...try this old military trick...use anti persperant on the feet for a week and you will find the feet will have low to no sweat for about 2 weeks...(it works on other places on the body as well.) don't be afraid to use antipersperant on places other than where you may use it now...that is what is was invented for
- consider using foot powder before bed
- Didn't Marmot use to make all bags with black liners so it would be easier to collect sunlight if you laid them out to dry?? Don't know why all heavy bag makers don't do that...
- (Someone actually told me they tried sleeping with a bag of dessicant! HA!)
HTH
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pastprime
Dec 15, 2006, 6:36 PM
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I will have to keep this short cause I get interrupted here at work. May stop and continue in another post if can't get the main points in.
My knowledge of VBL and the principles it works on come from extensive research done in the '70's by Camp 7, where the head designer was a friend and trip companion; and other companies who were looking into it with interest.
It is not simple to understand; (can't explain it to the average customer with some simple catch phrase); most customers aren't doing the kind of things where the benefits outway the drawbacks, and so most companies didn't pursue it. Camp 7 did, and had a small group of staunch followers, but too small to be a real market.
Camp 7 made a prototype bag and gave it to me to try out, which I did in summer and winter for about a year, after which they decided to put it into production. I ended up quite fond of it, and they made me a more refined version, which I then continued to use for many years after.
In the prototype/research phase, I was on several trips with reps from C7 and other companies where we were trying things out, and comparing bags and gear.
Gotta go. Be back.
(This post was edited by pastprime on Dec 15, 2006, 7:59 PM)
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pastprime
Dec 15, 2006, 7:03 PM
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Your skin gives off moisture in 2 ways. If it needs to cool, it sweats, and only (usually) sweats if you are too hot. It also has to maintain a humidity at the surface of about, or at least, 80%, and is constantly giving off insensable persperation (water vapor) to maintain that if the humidity at the skin surface falls below 80%. This vapor transfer is constantly cooling the skin, and the reason your hand feels warmer when you put it in a plastic bag (vapor barrier) is that the humidity quickly rises in the bag, and the cooling stops. The fact that you didn't know this does not keep it from being the way it is. This is the Vapor that the Barrier is contaning that the termVBL refers too.
If it weren't for the cooling caused by this insensible persperation, VBL's wouldn't be much warmer than any other piece of very thin cloth. A piece of dry cleaner bag around your hand, or body, will warm you quite a bit. It won't do much at all to keep your Nalgene full of warm water from cooling off, because the nalgene isn't being cooled by insensible persperation.
Most of the early points in your post about keeping warm I agree with. The balaclava is especially effective, explaining those reasons will be for another post.
As to not sleeping in your clothes, if you don't want to , don't, but taking a very light bag and making up the difference by wearing everything you have to bed has been standard alpine practice for years. It always worked for me (especially w. vbl) , and the people I climbed with, some of whom are fairly well known for having done some pretty impressive stuff.
Moisture in the insulation ina sleeping bag will move outward until it reaches an area in the insulation that is below the dew point, and there it will condense and remain until something else happens to drive it away.
In cold conditions, this dew point area is often somewhere in the outer layers of the bag, and that is why moisture collects there, and remains there (or redistributes itself more evenly while it is stuffed during the day) if you are jumping up in the morning, stuffing the bag right away, and getting going without having time to dry the bag. In such conditions, the bag usually gets wetter and wetter day after day. The great reduction of this moisture accumulation is one of VBL's main benefits.
For 1 or 2 nights one can usually live with,or not even notice, the moisture accumulation; if you are able to dry the bag daily it's not a problem; and at very high altitudes, the air is so very dry that moisture is often not a problem.
There are times; in the hands of someone who understands vbl so that using it in beneficial ways is almost automatic; when its benefits are great; but it certainly isn't for everyone. Its drawbacks, and the fact that most outdoorsy users don't get in conditions where its benefits matter much, is why it never has become standard gear. Its very real benefits in the hands of those who understand it, are the reason it is still around after all these years.
I'm not telling anyone vbl is for them. If you don't like it, don't use it.
The origional poster had a question about its use, I have a lot of experience with it and hoped my reply might be useful. Nothing I am saying is just based on how I imagine things probably are.
(This post was edited by pastprime on Dec 15, 2006, 7:45 PM)
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norm1057
Dec 15, 2006, 9:06 PM
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Excellent post and quite useful.
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slacklinejoe
Dec 15, 2006, 9:11 PM
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For those of you who don't actually understand what Vapor Barrier Layers do, read up a bit more on it at various alpine or backpacking sites. It's an interesting read to follow the evolution (if you can call it that) of the technique.
Here's one starting point: BackPackingLight.com reference to VBLs
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dalfollo
Dec 17, 2006, 8:46 AM
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For those interested in trying it out do a search for "Western Mountaineering HotSac VBL" on the bay...
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