Originally Posted by Michele
I'm really glad to see this being discussed as I've always figured VB's are the probably one of the few options for me to really get down into cold temps since I'm such a cold sleeper. Back in 2007 when I was going through GSMNP, a huge snow storm came through and we had 15 miles to go to get out of the park, and my feet were freezing from the trail being flooded with cold wet rain/snow/slush, so I had two thin newspaper sacks and decided to use them as a VB to keep my feet warm (never tried it before, just remember having read about it). I put the sacks on over my bare feet, then my socks over that and then my shoes. I was hiking in slushy freezing cold snow and my feet were totally warm UNTIL the thin plastic bags finally got small holes in them and then my feet were instantly flooded with freezing icy water. Talk about a shock to the system. Ever since I used those VB's I've been curious a/b them for sleeping in cold temps.
Well, Michelle, if you can't keep your feet warm without them, then it looks like your next step is to find a VB sock ( or clothing or bag liner whatever ) material that is tough enough to withstand the use you put it too. Over many years I got some small holes in my 1983 era Patagonia VB socks, which I patched like one would patch a tarp. Not many though, as the material was pretty tough. I still have those but am much more likely to use my Stephensons Warmlight fuzzy stuff VB socks as they have a liner built in and feel better to me than my Patagonias with a thin separate liner sock. But I have never hiked much in either of them, so I'm not all that rough on them. I have mainly used them for sleep or as camp wear(SP?). But I can sure see they might have a place in very cold, snowy hiking. A loan of my Patagonias instantly solved a severe cold feet problem for a buddy of mine while we were fishing. That, to me, was a sign.
Originally Posted by ka8yiu
Sailor, as I read it, I think the VB needs to be between you and the insulation, not outside the insulation. This would cause the moisture to build in the insulation and collapse the insulation.
Not sure as I'm still a novice on it.
Yes, absolutely! You may be a novice, but you are right on the money! The VB -IMO and per general VB theory as fa as I know - is meant to be as close to the skin as possible
. The only reason to wear anything under the VB is to decrease the unpleasant feeling of coated fabric and moisture on your skin, but nothing whatsoever is needed for the warmth function. A VB used any other way is pretty well going to leave a person hating VBs, and ending up wet and cold. Unless the VB is far enough away from your insulation so as to not cause trouble, like with a tarp for ex.
Guys/Gals, I think VBs are hard for some folks to comprehend only because it is exactly opposite of every thing we have ever been taught about how to keep warm, and why we must keep dry to do that. It is very hard to over come that bias, to the point that to purposely limit breathability seems almost stupid. It seems to be going in the opposite direction of where we should be going.
But in reality, like so many things here, once you get the theory it is all about as dirt simple as anything could be. Just think: opposite of breathable, but keep all the moisture close to the skin, keep it from evaporating ( evaporative cooling = swamp cooler/air conditioner), and keep that moisture- a little bit or a gallon- out of your precious insulation.
If you leave out the increased warmth factor, and probably even more important leave out the huge benefits of dry insulation after a week or three in the wild, then I don't think a VB will ever be as comfortable as nice breathable system. (Even though my Stephensons WL shirt has been coming close most of the time). It is just not as comfortable to have a sensation of damp or outright wet against your skin, no way. But for me, when throwing in the other benefits has sometimes made it a no brainer trade off. Plus growing skill with use has been minimizing the sensation of dampness/uber high humidity.
So, if you are a person who:
1: has decided they are always going to sweat no matter what, then there might
be an advantage to figure out how to keep that sweat from evaporating/cooling and finding a way to keep it out of your insulation.
2: if you are in a group of folks who consistently find ( like a buddy of mine ) that after a cold week your quilts have a little less loft each day and weigh more at the end of a trip, even though no external moisture touches your quilts, you might
want to figure out a way to keep your body moisture ( either vapor or liquid/sweat) out of your insulation in the first place. Rather than keeping on in the hope that all of that moisture making it to the outside of your insulation before it condenses into liquid. Maybe, but to each his own, and HYOH, etc.
There are several different types of VB. Like a tarp or pad or an HHSS UC, not meant to function as a VB, because the VB space blanket is meant to (hopefully) serve as the VB which keeps your body's moisture from reaching it in the first place. Also VB bag liners, and VB clothing.
But applicable to all of them, these general rules:
1: keep the VBs warm by keeping them close to your skin. Vapor condenses on cold surfaces, not warm ones.
2: Manage ( maybe reducing ) your insulation so that you don't over heat and sweat. Maybe even start out a little cold, add insulation as needed. You might need a lot less insulation than you do without a VB. Which might be a good thing, right?
3: if you do over heat and sweat any way, it might be safer to keep the sweat next to your skin than allowing it to get into your insulation
. Which you find out about when you stop to rest and suddenly freeze, because your insulation is wet from sweat/condensation, even though your rain gear has kept all external moisture on the out side.
But, it is a learning curve! I'm still on this curve!