Vapor barriers -what is your opinion?

[OneClick]

If nothing else, it's always fun to watch your skin steam after removing the VB!

This was after hiking in at about 5°F for a high and close to 0° once at camp last weekend. After an EXHAUSTING 5 hour snowshoe hike in 14" of fresh snow, dragging a ~60lb pulk, there was no detectable sweat even with thick wool socks over the VB and warm boots (Salomon Toundra). Just a clammy feeling that was gone by the time I put fresh socks on.



Again, there's really no need to ever have cold feet with this system.

[m00ch]

I'm about to jump on board and try the vapor barrier but I do have a question. So let's say I hike in today for a 3 night trip (It's -22F right now). When do I take the vapor barrier off? It seems that leaving it on for the 4 days would be unsanitary but taking it off would just freeze the sweat inside it. I am probably missing something simple here.

[Groundskeeper]

That is my question also. I am on board for in camp and for sleeping, but have no idea how it will work on the trail. I know the theory is to slow down and vent when you feel the sweat building up, but historically I have always just plowed ahead. I expect this would result in a sweaty mess under the VB. I'm not sure how to deal with that.

[OneClick]

Like I mentioned above, no sweat after that strenuous 5 hour hike. I took the VB off around 6pm, then just took it easy around camp. I could have put it back on, but I figured a little moisture would be fine, if any. Obviously off at night. Back on in the morning if I felt it to be necessary. But on this trip, I switched to my N1B mukluks which breathe well so I skipped the VB going forward.

In another thread I mentioned how I tested this while jogging, trying to get sweat to build it. It didn't. Strange, but it works. But the temps have to be right...don't try that at a "warm" 25°.

[m00ch]

I am confused “obviously off at night”.... I thought we were trying to keep our moisture out of all of our insulation, day or night.


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[OneClick]

I am confused “obviously off at night”.... I thought we were trying to keep our moisture out of all of our insulation, day or night.

At night it's all or nothing. Simply blocking vapor from your feet won't really cut down on a damp sleep system. You need to let them air out at some point; overnight is a great time when you're not active. I'm considering a full VB bag liner after my damp trip last weekend.

Since my feet get cold first, and sweat soaks boot insulation quickly (and NEVER dries out), that is my first and only use for a VB so far.

[BillyBob58]

Vapor Barrier experimentation

I have been reading the vapor barrier discussions both past and present with a morbid fascination. When I first came across it my thoughts were “What kind of idiot wears a sweat suit in the winter?” Yet, as my reading continued there were nuggets of information that slowly sunk in. BillyBob58 is nothing if not persistent. There was anecdotal evidence, there was use of VB’s by Andrew Skurka. Maybe I was missing something.

Finally while reading this thread it finally sunk in. It is the evaporative cooling element that got me to thinking this could work. Sure, containing the moisture keeps your insulation dry, but what I saw as a great value was stopping evaporative cooling. I think the reason it took so long to understand this was that I never thought of evaporative cooling in a cold environment. But the laws of physics do not suspend there self just because it gets cold.

When I got up in the morning to get ready for work it was 9 degrees, my new personal best, and other than my nose and left foot, everything was warm and dry. No frost, but the balaclava and opening of the down hood were rather soggy. The only things that got cold were the areas NOT covered by vapor barrier: My face (really my nose) and my left foot (which, as you may recall, was only in wool socks, not the waterproof VB sock).

BillyBob58, I hereby apologize for anything I may or may not have muttered about your intelligence and good sense regarding vapor barriers. Now I will be investing in some of those sexy Warmlite VB clothes. ..................

Elmer, coming in from my own VB testing, I almost spit my coffee out reading your comments about my probable imbecility! And I know it is true, I think there are more than a few here that question my sanity because of a few of my opinions that, shall we say at a minimum, do not agree with the conventional wisdom. And I actually understand that, because even though I think science supports some of my theories and experience(I have been playing with VBs since 1983, first time I got the nerve to try some socks), they at the same time go against almost everything we have been taught about the holy grail of breathability. How can two opposites be right? Well, maybe they can, depending on conditions and needs. And I will still choose nice and breathable when conditions allow. But I also know that under some conditions- maybe I'm having trouble keeping warm, maybe my loft is starting to decrease and there are many more days on the trail with no possibility of drying- a VB can be my best solution. Maybe even better than adding additional thicker, heavier, bulkier, more expensive insulation. All of us who have ever slept out under the stars, and awakened to find our bag/quilt covered in thick frost or dew(even if the ground is not) know this intuitively. That is our insensible perspiration, which has evaporated and cooled us down, that has now traveled far enough from our bodies and condensed back into liquid or ice. Do people really have that much confidence that all of that condensation has taken place on the outside of their breathable DWR quilt shell, and none just a 1/4" inside? Really? Well, in my experience, if they do believe that, after enough days on the trail, the decreasing loft of their down quilts will maybe convince them otherwise.

But looks like you have decided to do the sciency thing and PUT IT TO THE TEST! And it appears that for your experiment, the science has worked as theory had predicted. Welcome to the science nerd club!

Somewhat related: when I first started playing with Patagonia VB socks, it was 1983 in the mountains of northern AZ, when I lived in Flagstaff. They were an immediate huge help with my cold feet as well as a buddy's cold feet. At least once, they saved the day. Shoot forward 30+ years to HF, and a young man who wrote a book on hammock camping "The Ultimate Hang", starts a thread here on VB theory. Derek Hansen, aka Dejoha. Some months after that thread, he is on a hike and realizes he is going to have an unpleasantly cold sleep, despite gear rated for the temps. He remembers what he wrote about VBs, and since chance of rain is about zero, he decides to PUT IT TO THE TEST! And wraps up in his tarp, under his quilt. Result: a very warm and comfy night. VBs saved the day(or night)! And where was this? In the mountains of AZ, I think in the San Fran Peaks outside Flagstaff.

Anyway, welcome to the club, brother! (it will likely remain a small club though)

[m00ch]

Got it, I misunderstood and thought that you were trying to keep your sleep system dry also.



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[slugbait]

Long ago I experimented with DIY vapor barrier clothing on an overnight trip (pre-hammock). It got down to zero at night. I wore the clothing continually for the whole trip and they seemed to help. I was amazed when I changed clothes at the end of the trip that my skin was dry and I felt fresh- not all stinky. The theory put there is that your skin seeks a certain moisture level and automatically keeps it there, unless you allow excessive sweating. If I were to go out in such temps again(I don't plan to) I would certainly use vapor barriers.

[m00ch]

BillyBob- Let’s say I want to go all in and join the club, is there a certain company or mix of companies that you would go with for a complete system?


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