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TX Aggie
02-05-2018, 16:02
Curious if any of you have tried vapor barrier clothes, primarily for sleeping not while hiking.

It seems like there are only a couple of places that offer them, and they seem a bit on the expensive side.

I was wondering if anyone had ever tried those sauna suits used for sweating weight loss would work. There doesnít seem to be much non-breathable clothing out there except for those couple of sites. Iím half tempted to see if my wife can make something out of silpoly tarp material.

Venchka
02-05-2018, 16:26
Western Mountaineering sells a vapor barrier sleeping bag liner. Itís not terribly expensive.
Never done it, but the theory is that it has to be really cold and dry to work. Negative double digits cold. Youíll also need a suitable negative double digit sleeping bag.
Good luck and have fun!
Wayne

kestral
02-05-2018, 16:32
Dumb question maybe, but why would you want this garment?

unsure of weights, but you could use the ultra cheep rain pant and jacket I have seen in Walmart and other discount stores which is basically plastic, or use a construction sized trash bag cut and then taped together to use as a sleeping bag inner liner. Again, I’m not seein the advantage, I pay extra for breathable stuff as I hate to be sticky, stinky, sweaty if I don’t have to be.

As as a construction material for make your own garments consider the polycro window liner stuff on amazon. An inexpensive alt to silnylon for initial diy project. Can seam seal with tape or a small iron that can be found in craft stores. Or cut up large trash bag or plastic sheeting for initial trials until happy with patterns. (I do this with heavy duty plastic sheeting) you can sew on machine with fine needle and thread and long stitch width on plastic. It doesn’t hold well, but again I use for prototype before the fanicy material investment.

DIY can be fun; HYOH!

moldy
02-05-2018, 16:45
You don't want to sleep in such a thing. You will be amazed at just how wet you are going to get. I spent the night in a shelter with this young guy who thought he could fight off the cold by putting his feet and legs in a large black plastic bag then got inside his sleeping bag. The plastic bag had a few small holes in it and the water just poured through the holes and got his sleeping bag wet. He was not a happy camper by morning.

Venchka
02-05-2018, 16:52
You don't want to sleep in such a thing. You will be amazed at just how wet you are going to get. I spent the night in a shelter with this young guy who thought he could fight off the cold by putting his feet and legs in a large black plastic bag then got inside his sleeping bag. The plastic bag had a few small holes in it and the water just poured through the holes and got his sleeping bag wet. He was not a happy camper by morning.
Precisely why VBL use is limited to very cold and consequently very dry conditions. Everest was a good place for a VBL once upon a time.
Wayne

Tipi Walter
02-05-2018, 17:08
You don't want to sleep in such a thing. You will be amazed at just how wet you are going to get. I spent the night in a shelter with this young guy who thought he could fight off the cold by putting his feet and legs in a large black plastic bag then got inside his sleeping bag. The plastic bag had a few small holes in it and the water just poured through the holes and got his sleeping bag wet. He was not a happy camper by morning.

My experience precisely. Backpacking and living outdoors is hard enough---as is sleeping in a tight zipped up sleeping bag every night for dozens of nights. Why make it so much more worse by sleeping in a watertight wet bag??

Plus, I have found no need for any kind of VBL paraphernalia in the Southeast winters with temps down to -10F. A good down overkill bag will provide enough warmth and stay condensation-free and dry for long uninterrupted trips. There's no "build up" of down wetness over the days rendering your bag useless. Needing VBL gear may be true for backpackers living out at -30F for weeks at a time---but we don't need VBL stuff in the mountains of NC and TN and Georgia and Virginia in order to stay warm or "warmer".

TX Aggie
02-05-2018, 17:13
Dumb question maybe, but why would you want this garment?

unsure of weights, but you could use the ultra cheep rain pant and jacket I have seen in Walmart and other discount stores which is basically plastic, or use a construction sized trash bag cut and then taped together to use as a sleeping bag inner liner. Again, Iím not seein the advantage, I pay extra for breathable stuff as I hate to be sticky, stinky, sweaty if I donít have to be.

As as a construction material for make your own garments consider the polycro window liner stuff on amazon. An inexpensive alt to silnylon for initial diy project. Can seam seal with tape or a small iron that can be found in craft stores. Or cut up large trash bag or plastic sheeting for initial trials until happy with patterns. (I do this with heavy duty plastic sheeting) you can sew on machine with fine needle and thread and long stitch width on plastic. It doesnít hold well, but again I use for prototype before the fanicy material investment.

DIY can be fun; HYOH!

Just looking for cheap options, and Iíve seen decent sauna suits for around $20. I originally looked at rain gear, but itís becoming increasingly difficult to find non-breathable rain gear. I was wondering about a couple of the cheaper ones would work.

Thanks for the suggestions.

TX Aggie
02-05-2018, 17:14
Precisely why VBL use is limited to very cold and consequently very dry conditions. Everest was a good place for a VBL once upon a time.
Wayne

This is the only reason Iím looking, specifically for extended sub-freezing trips.

Tipi Walter
02-05-2018, 17:18
This is the only reason Iím looking, specifically for extended sub-freezing trips.

I just got back from a 20 day January trip with consistently subfreezing temps in 10 consecutive days etc. Every night ranged from 12F down to 0F and all my down items kept me alive and warm. Sometimes a moist wind blows, sometimes a bone dry wind blows---and it's bone dry (air humidity) days which "sublimates" your geese and relofts everything.

But heck some people might love the clammy feel of sleeping in VBL gear. I avoid it.

Traffic Jam
02-05-2018, 19:27
I just got back from a 20 day January trip with consistently subfreezing temps in 10 consecutive days etc. Every night ranged from 12F down to 0F and all my down items kept me alive and warm. Sometimes a moist wind blows, sometimes a bone dry wind blows---and it's bone dry (air humidity) days which "sublimates" your geese and relofts everything.

But heck some people might love the clammy feel of sleeping in VBL gear. I avoid it.

Me too.

If anyone is interested in experimenting at home, try a pair of knee-high, surgical, foot covers for about 30 minutes.

Dogwood
02-05-2018, 21:44
Curious if any of you have tried vapor barrier clothes, primarily for sleeping not while hiking.

It seems like there are only a couple of places that offer them, and they seem a bit on the expensive side.

I was wondering if anyone had ever tried those sauna suits used for sweating weight loss would work. There doesn’t seem to be much non-breathable clothing out there except for those couple of sites. I’m half tempted to see if my wife can make something out of silpoly tarp material.

Before having your wife go through such efforts try sleeping in like real world conditions and sleep set ups at home in the yard employing a cheapie non permeable big box hardware store rain jacket, pants, and Superman like boots. One thing you'll find is there certainly is a difference between breathable rain pants and jacket and non permeable non breathable ones.


It depends on your goal. For 98% of trips wishing to go with a down bag/quilt I find better approaches for myself to conserve loft either wearing breathable rain pants and jacket as permeable/breathable pseudo VBL apparel incorporated into the sleep system, getting to a dryer(if I have access), and/or incorporate hydrophobic downs. At some point I switch to one of the latest synthetic bags/quilts. Tipi recently said he gets by using a down bag based on his length trips by going with a lower rated temp bags expecting to lose some loft over his typical 10-14 day winter trips.


Andrew Skurka, based on his trips and approaches, wore VBL apparel both while on the move and incorporated into his sleep system on some trips. Andrew wrote up I think at least two VBL apparel articles worth a read.

Dogwood
02-05-2018, 21:49
Tipi also spends time drying his down bag and outside of it which can cut down on loft collapse. My guess is he's not spending much time letting himself get into a sweat fest mode especially during those 2 wk + winter trips.

Dogwood
02-05-2018, 21:51
This is the only reason I’m looking, specifically for extended sub-freezing trips.

Andrew wrote up his articles based on this type of trip.

Dogwood
02-05-2018, 21:54
My experience precisely. Backpacking and living outdoors is hard enough---as is sleeping in a tight zipped up sleeping bag every night for dozens of nights. Why make it so much more worse by sleeping in a watertight wet bag??

Plus, I have found no need for any kind of VBL paraphernalia in the Southeast winters with temps down to -10F. A good down overkill bag will provide enough warmth and stay condensation-free and dry for long uninterrupted trips. There's no "build up" of down wetness over the days rendering your bag useless. Needing VBL gear may be true for backpackers living out at -30F for weeks at a time---but we don't need VBL stuff in the mountains of NC and TN and Georgia and Virginia in order to stay warm or "warmer".

That's one viable approach that you take as you well know Tipi but there are other approaches where VBL's may work in the southeast as well BASED ON THEIR TRIPS.

TX Aggie
02-05-2018, 22:23
Before having your wife go through such efforts try sleeping in like real world conditions and sleep set ups at home in the yard employing a cheapie non permeable big box hardware store rain jacket, pants, and Superman like boots. One thing you'll find is there certainly is a difference between breathable rain pants and jacket and non permeable non breathable ones.


It depends on your goal. For 98% of trips wishing to go with a down bag/quilt I find better approaches for myself to conserve loft either wearing breathable rain pants and jacket as permeable/breathable pseudo VBL apparel incorporated into the sleep system, getting to a dryer(if I have access), and/or incorporate hydrophobic downs. At some point I switch to one of the latest synthetic bags/quilts. Tipi recently said he gets by using a down bag based on his length trips by going with a lower rated temp bags expecting to lose some loft over his typical 10-14 day winter trips.


Andrew Skurka, based on his trips and approaches, wore VBL apparel both while on the move and incorporated into his sleep system on some trips. Andrew wrote up I think at least two VBL apparel articles worth a read.


Andrew wrote up his articles based on this type of trip.

His articles are a couple of the ones that got me thinking along these lines. I donít do THAT many winter trips, but I do like experimenting. During the winter I hang in my backyard almost every weekend and I try different setups for the cold, which is why I thought I might try the cheap sauna suits first. If it works, great if not, Iím only out 20 bucks.

Dogwood
02-05-2018, 22:37
A cheapie rain suit(jacket and bibs/pants) at HD can be had for that price. Add in some bread bags for the feet with some rubber bands around wrists and ankles. If it doesn't work out throw it in the trunk of the car for changing a flat in the rain.

MuddyWaters
02-05-2018, 23:04
Curious if any of you have tried vapor barrier clothes, primarily for sleeping not while hiking.

It seems like there are only a couple of places that offer them, and they seem a bit on the expensive side.

I was wondering if anyone had ever tried those sauna suits used for sweating weight loss would work. There doesnít seem to be much non-breathable clothing out there except for those couple of sites. Iím half tempted to see if my wife can make something out of silpoly tarp material.

You've gotten some good answers.
While Vapor Barrier can add a few degrees of warmth maybe up to 10 f, it can makes you soaking wet. In the morning you will freeze your dingleberries while changing. In cold and dry conditions you will quickly dry up. In cold and damp conditions not so .

The best use is really for extending life of insulation by minimizing moisture accumulation during extended Backcountry trips below freezing. In all other circumstances, a couple extra ounces of down will be lighter and way more comfortable and effective.

Some manage this moisture accumulation a different way, by bringing an overkill bag and taking time to dry it in the sun each day. Generally, on the trail if you're in town every several days moisture accumulation is not a big problem, if you have the chance to pop your stuff in the dryer.

Overkill bags have another benefit. When there to warm you leave them unzipped to ventilate, thereby reducing the bodys respiration moisture that has to migrate through the down and condenses there. So they may pick up moisture slower as well.

Kfried
02-05-2018, 23:15
Rbh designs is awesome. Socks are a good way to start to see how you like it (would not recommend Stephenson warm lite over Rbh). I've been on many trips in the winter where I was the only warm person in the group. Dry insulation is important and vbl really helps. My view is you either like it, or you hate it. I wouldn't go winter trekking without it. Generally from 0 to 25 I wear a short sleeve poly pro shirt under a vbl shirt and vent with a light down vest unzipped over the top. Very nice to put on dry boots in the morning I didn't sleep with.

Dogwood
02-05-2018, 23:17
Andy also benefitted by wearing his VBL as part of his layering, thermoregulation, wt, and volume reduction approach where he was out for wks between resupply or a town stop with reg dryer access. He tends to always be on the move too. I find it interesting to consider what he does in context of his approaches and endeavors.

Dogwood
02-05-2018, 23:20
Rbh designs is awesome. Socks are a good way to start to see how you like it (would not recommend Stephenson warm lite over Rbh). I've been on many trips in the winter where I was the only warm person in the group. Dry insulation is important and vbl really helps. My view is you either like it, or you hate it. I wouldn't go winter trekking without it. Generally from 0 to 25 I wear a short sleeve poly pro shirt under a vbl shirt and vent with a light down vest unzipped over the top. Very nice to put on dry boots in the morning I didn't sleep with.

And, in this way you avoid the clamminess while preserving your main insulation pieces as the outer most layer. There you go.

TX Aggie
02-06-2018, 07:49
Rbh designs is awesome. Socks are a good way to start to see how you like it (would not recommend Stephenson warm lite over Rbh). I've been on many trips in the winter where I was the only warm person in the group. Dry insulation is important and vbl really helps. My view is you either like it, or you hate it. I wouldn't go winter trekking without it. Generally from 0 to 25 I wear a short sleeve poly pro shirt under a vbl shirt and vent with a light down vest unzipped over the top. Very nice to put on dry boots in the morning I didn't sleep with.

What shirt are you using?


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1azarus
02-06-2018, 19:07
I do believe in vbl -- at least stuff like Rbh makes. I did try a cheap sauna suit -- brought it on a long winter section hike about ten years ago. It ended up in the motel garbage. A few issues: I was always reluctant to strip down to bare to put on the pants (and to take them off in the morning)... and they weighed a ton! For more serious winter hiking I would be interested...

Venchka
02-06-2018, 19:27
This is the only reason Iím looking, specifically for extended sub-freezing trips.
As Tipi Walter states, sub-freezing isnít cold enough to require a vapor barrier. Read some of the high altitude climbing literature for cases where a vapor barrier was instrumental in survival.
What does your current sleeping system consist of? What locations and conditions does it fall short in?
Wayne

TX Aggie
02-07-2018, 00:02
As Tipi Walter states, sub-freezing isnít cold enough to require a vapor barrier. Read some of the high altitude climbing literature for cases where a vapor barrier was instrumental in survival.
What does your current sleeping system consist of? What locations and conditions does it fall short in?
Wayne

I understand itís not required, that not the point. The point is to explore and learn different systems. Iím not advocating, Iím asking for learn from those who HAVE had success, because Iím bullheaded and typically ignore the naysayers. I respect a lot of the information you and Tipi bring, but that doesnít mean Iíll agree 100% of the time.

As for my system, I Hammock and use a 0* underquilt and a 20* topquilt that Iíve augmented and had down to 0*.

One of the reasons Iím asking is because on the same trip, one of the guys in my group slipped in a creek and got pretty drenched from the chest down. The high for the day was in the low 20ís and we decided out of safety to cut our trip a day short. Luckily, we were only about an hour from a ski resort and he was able to bail out there while we made the 7 mile trek back to the cars.

Now, if we had been much farther away, it could have gotten a little dicier. So the question arises: would VBLís have kept him warm enough if the need arose? Would they be as effective after falling in? Would they have helped keep him warm if he was wearing them when he fell in? In the creek crossings, Iím 100% certain that I would have benefitted from VBL socks, and my boots kept me dry until the last few miles. From other accounts Iíve read, people are having very good success with Trail runners and VBL socks when normally they would have switched to boots.

So itís not a matter of need, just like a sub 10 lb base weight isnít a need. Itís learning new techniques and finding out what works for each person.

Venchka
02-07-2018, 00:40
Thatís an interesting story. Iím glad it worked out well for your friend. Soaked in those conditions doesnít always work out for the best.
Good luck with your research.
Wayne

TX Aggie
02-07-2018, 09:59
Thatís an interesting story. Iím glad it worked out well for your friend. Soaked in those conditions doesnít always work out for the best.
Good luck with your research.
Wayne

Yeah, lucky we were in a good location and it happened early in the day giving us enough time to bail.
Thanks again for your input.


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reppans
02-07-2018, 13:48
I'm admittedly not a big winter camper, but do enjoy winter hiking and backcountry XC skiing. Getting soaked with ice water in that weather is awful (I was in a high school polar bear club) but with hiking partners around, a life threatening situation could be turned into more of an inconvenience. Collectively, I'm sure there's enough spare clothing for a complete dry warm outfit and plastic/dry bags for the wet boots. Uncontrollable shivering with the onset of hypothermia could be quickly quelled with the Palmer survival furnace technique which I often use as campsite luxury just by multi-tasking my existing gear - full body micro climate in a few minutes that can actually be 'hot'. Then at the group's leisure, use a campfire to dry out the wet gear (assuming the guy's pack wasn't submerged long enough to soak his sleeping bag).

I'm also interesting the VB concept as I sometimes use non-breathable insulation (my tent/poncho) for loft as a 'down' vest/sweater mid-layer. Here's a guy on another forum that regularly sleeps in a VB, even in warmer temps - he mentions (similar to Andrew Skurka) that the body gets used to it and will regulate perspiration to level of high humidity, yet not dripping/soaking wet. Maybe you could PM him there....clicky (http://www.survivalistboards.com/showpost.php?p=17520953&postcount=11).

Dogwood
02-07-2018, 18:24
I understand it’s not required, that not the point. The point is to explore and learn different systems. I’m not advocating, I’m asking for learn from those who HAVE had success, because I’m bullheaded and typically ignore the naysayers. I respect a lot of the information you and Tipi bring, but that doesn’t mean I’ll agree 100% of the time.

As for my system, I Hammock and use a 0* underquilt and a 20* topquilt that I’ve augmented and had down to 0*.

One of the reasons I’m asking is because on the same trip, one of the guys in my group slipped in a creek and got pretty drenched from the chest down. The high for the day was in the low 20’s and we decided out of safety to cut our trip a day short. Luckily, we were only about an hour from a ski resort and he was able to bail out there while we made the 7 mile trek back to the cars.

Now, if we had been much farther away, it could have gotten a little dicier. So the question arises: would VBL’s have kept him warm enough if the need arose? Would they be as effective after falling in? Would they have helped keep him warm if he was wearing them when he fell in? In the creek crossings, I’m 100% certain that I would have benefitted from VBL socks, and my boots kept me dry until the last few miles. From other accounts I’ve read, people are having very good success with Trail runners and VBL socks when normally they would have switched to boots.

So it’s not a matter of need, just like a sub 10 lb base weight isn’t a need. It’s learning new techniques and finding out what works for each person.


TXAggie, your perspective displays a lot of maturity, character, and willingness to consider beyond current personal comfort zones. It all leads to a greater awareness.


Enjoyed contemplating your questions. No, I don't want to answer any of them as I've virtually zero personal true VBL experience. I'd like to hear more from others though about VBLing including providing answers to your questions.

TX Aggie
02-07-2018, 22:14
TXAggie, your perspective displays a lot of maturity, character, and willingness to consider beyond current personal comfort zones. It all leads to a greater awareness.


Enjoyed contemplating your questions. No, I don't want to answer any of them as I've virtually zero personal true VBL experience. I'd like to hear more from others though about VBLing including providing answers to your questions.

If youíre calling me mature.....you donít know me very well! [emoji41]

Every now and then a topic grabs my attention and I try and learn as much as I can. Often it just seems to be the obscure things.

sethd513
02-08-2018, 11:03
I use a warm lite vapor barrier suit in winter. When I first started using a bivy I would not accept the thought that pertex didnít breath. So I looked on how to fix it. Vbl suit was the only answer I could find other then a better bivy. When I bought mine they were still in nh and prices were much lower. If the pertex bivy top was open Iíd have no condensation/frozen quilt in the morning. I donít get to go out for weeks on end in any season. But I want to make sure my system will withstand abuse if the time comes that it needs to shine.

My last trip this weekend hovered around 2* with a -25 wind chill. I was uncomfortably warm in my -20 bag without a bivy but I had my vbl suit on. Standing in camp with the least amount of close Iíve worn and taken I was extremely comfortable. My cousin woke up after a fridged night with a wet bag. The worst part for me was changing back into my day layer that morning as I was clammy.

Hiking in winter I wear
-base layer
-softshell
-hardshell
And down when setting up camp.

At night what I do now is put on my vbl and I can do one of two things. I can put a softshell layer over it or my base layer from the day. I now know that I donít need extra fleece above 0. I also donít need extra base layer shirt. Saving me almost 20oz. Vbl for me is my ďextra layerĒ but I need to use my other layers properly during the day to make it work.


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sethd513
02-08-2018, 11:08
I should also add I fit cold fingers/toes. I use a bread bag against my feet during the day and when my fingers start going down hill which when they do they numb out fast, I throw my vbl gloves on. They are great as they fit under a fleece and inside every glove or mitten combo I have plus they are easy on and off. Not like a regular painter/doctor/mechanics plastic glove.


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TX Aggie
02-08-2018, 11:48
I should also add I fit cold fingers/toes. I use a bread bag against my feet during the day and when my fingers start going down hill which when they do they numb out fast, I throw my vbl gloves on. They are great as they fit under a fleece and inside every glove or mitten combo I have plus they are easy on and off. Not like a regular painter/doctor/mechanics plastic glove.


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Thank for the info, sounds like youíve found a very workable solution. Two quick questions:
Have you tried wearing the VBL while hiking?
Where did you find VBL gloves? Iíve seen mittens, but not gloves.

TX Aggie
02-08-2018, 11:50
I should also add I fit cold fingers/toes. I use a bread bag against my feet during the day and when my fingers start going down hill which when they do they numb out fast, I throw my vbl gloves on. They are great as they fit under a fleece and inside every glove or mitten combo I have plus they are easy on and off. Not like a regular painter/doctor/mechanics plastic glove.


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Skip the gloves question, I just realized Warmlite has them.

sethd513
02-08-2018, 13:05
Thank for the info, sounds like youíve found a very workable solution. Two quick questions:
Have you tried wearing the VBL while hiking?
Where did you find VBL gloves? Iíve seen mittens, but not gloves.

Oh Iíve worn it hiking. I think vbl are best for low to no intensity output. I was soaked. Intern everything got soak and I woke up to a frozen quilt system at 3 am. I had to put my goggles on to boil water as my eye lashes were freezing together it was so cold.

If you needed to as a bail out option hiking in them would retain a ton of heat. If you were maybe dog sledding or something along those lines it would keep you warmer then without. But you end up with wet skin as I believe warm lite says the vapor transfer is 7 times slower with their suit. Iím very happy with warm lite. Kim can help you with sizing and order questions.


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TX Aggie
02-08-2018, 13:48
Oh Iíve worn it hiking. I think vbl are best for low to no intensity output. I was soaked. Intern everything got soak and I woke up to a frozen quilt system at 3 am. I had to put my goggles on to boil water as my eye lashes were freezing together it was so cold.

If you needed to as a bail out option hiking in them would retain a ton of heat. If you were maybe dog sledding or something along those lines it would keep you warmer then without. But you end up with wet skin as I believe warm lite says the vapor transfer is 7 times slower with their suit. Iím very happy with warm lite. Kim can help you with sizing and order questions.


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Great info, thanks!


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Pinnah
02-08-2018, 19:50
TL/DR: VB socks while moving, to keep boots dry. No more frozen boots in the morning. VB shirt in camp to dry fleece and keep warmer sleeping.

VERY long version

** DAVE'S VAPOR BARRIER FAQ **

CONTENTS:
1) What's in this file?
2) What are Vapor Barriers and what do they do?
3) How do Vapor Barriers protect your insulation?
4) How do Vapor Barriers stop evaporative cooling?
5) Why won't I sweat to death? (The controversial stuff)
6) What kinds of VBs are available?
7) Do VBs work?
8) When and how should I use VB sleeping bag liners?
9) When and how should I use VB socks?
10) When and how should I use VB clothing?
11) What about VB-like clothing?



-------------------------- * -------------------------------

1) What's in this file?

What follows is a hodge-podge of information and ideas about
Vapor Barriers (VBs) that I have culled from the lively discussions
on the topic in rec.backcountry combined with some of my own
personal experiences. Note, I am not a physicist nor a
physiologist, although several of those who've helped are. I am
in much debt to them for the insights and information they
have provided.

-------------------------- * -------------------------------

2) What are Vapor Barriers and what do they do?

A vapor barrier (VB) is a non-breathable layer that is added
to a clothing or sleep system with the goal of keeping you warmer.
What they actually *do* is to prevent water vapor from passing
from one layer to the next. Hence the name - vapor barrier.

Stopping water vapor from moving from one layer to the next
has 2 primary effects:
a) It protects insulating layers from getting wet from moisture
produced by the body
b) It stops the process of evaporative cooling which can continue
to make you cold, even when you are at rest

Note, for the sake of clarity, I find it useful to
separate what VBs do (prevent moisture transport) and
their effects (protect insulation and physiological effects).
I think the failure to make this distinction clear is at
the root of many of the heated discussions I have heard
surrounding VBs and their use.


-------------------------- * -------------------------------

3) How do Vapor Barriers protect your insulation?

To stay warm, it is important to keep your insulation layers
dry. Surprisingly, the biggest culprit for getting insulation
layers wet when winter camping is often your body's own sweat.
Our bodies sweat even during even during times of relative
inactivity, like when sleeping.

The effects of sweat condensing and freezing in insulation
is typically cumulative; getting worse with each passing day
you are out. In his book recounting his crossing of Antarctica,
adventurer Will Steger noted that their synthetic sleeping bags
became so full of ice they weighed an astonishing 20 lbs each
and were impossible to pack. Realistically, most of us will
only go on winter trips measured in days, not weeks or months.
Still, if you want to prevent sweat from condensing in
your insulation, VPs provide a solution.


-------------------------- * -------------------------------

4) How do Vapor Barriers stop evaporative cooling?

Most of us understand that when sweat evaporates off of our
skin, it cools our bodies. Not surprisingly, the process is
called evaporative cooling and it's good news for us when
we're working hard and hiking up a steep hill.

What is less well known is that our bodies continue to
produce sweat, even when we are cold. To prevent our skin
from drying up like rice paper, our bodies pump out moisture
any time the air near our skin lacks humidity. This is
sometimes called "insensible perspiration" because, unlike the
sweat rolling off our brow like when we're hiking, we typically
don't sense this kind of perspiration.

What this means is that when you are shivering in your sleeping
bag, your body is almost certainly perspiring. This is bad
news, because as that sweat is evaporating off of your skin,
the process of evaporative cooling is making you colder.

However, if you have a VB layer near your skin, the air
between your skin and the VB soon becomes super humid,
effectively preventing sweat from evaporating from your
skin. In short, VBs stop the process of evaporative cooling.


-------------------------- * -------------------------------

5) Why won't I sweat to death? (The controversial stuff)

The claim is that VBs can, under the right conditions,
dramatically slow down, or entirely stop, the rate of
insensible perspiration. Specifically, the claim is
that our bodies will only perspire for one of two reasons:
a) our body core is hot or
b) our skin is dry.

So, proponents of VBs will argue that once the air inside
of the VB gets humid enough your body will stop perspiring,
provided that you don't overheat and begin to sweat in an
attempt to cool off.


-------------------------- * -------------------------------

6) What kinds of VBs are available?

I group VBs into 3 categories:
+ VB liners for sleeping bags
+ Bags with built in VBs
+ VB clothing

SLEEEPING BAG LINERS
The cheapest VB bag liners can be easily made from a couple
of Hefty bags, some duct tape, nylon cord and imagination.
Not very durable but, it's a great way to begin experimenting
with the concept.

VB liners are also made a variety of equipment manufacturers,
and are generally out of coated nylon. The North Face has made
them in the past, as has Marmot.


SLEEPING BAGS WITH BUILT-IN VBs
There is currently only one sleeping bag on the US market that
I am aware of that incorporates a built-in, permanent VB; the
Stephanson Warmlite bag. Stephanson uses his own non-breathable
"Fuzzy Stuff" material to line the bag. It is so named for the
soft, fuzzy synthetic facing on the fabric.


VB CLOTHING
With regards to VB clothing, few companies are currently producing
them. Stephanson produces shirts, pants, and socks. Black Diamond
and Climb High both make VB socks. Occasionally, you will even
see non-breathable neoprene socks and gloves being sold for
winter use.

As with VB bag liners, you can often make your own VB clothing.
Long thin plastic bags like those that wrap your local newspaper
or those found in the vegetable section of the grocery store make
workable VB socks. They fit poorly and tear easily but they are
cheap and allow you to easily experiment.

Light, coated nylon rain gear makes workable VB shirts and pants.
In order to save weight, you may want to chop the hood and extra
pockets off of a rain jacket to convert it to a VB shirt. You
may also want to size it smaller than normal to fit *under* your
insulating layers, not over them. And you may want to seal off
any ventilation features on the jacket in order to use it as a
VB shirt.


-------------------------- * -------------------------------

7) Do VBs work?

This is perhaps the most commonly asked question
with regards to VBs. The answer depends entirely on what
is meant by 'work'?

If 'work' means preventing water vapor from passing to
your insulation layers, then the answer is yes, up to the
waterproofness of the VB. This is, after all, what VBs
really *do*.

For example, Plastic VB bag liners held together by tape are
very efficient. On the other hand, a sleeping bag with
a built in VB having a large number of unsealed seams
may work somewhat less well as water vapor may escape
through the needle holes. Whether or not this is enough
to allow a significant amount of water vapor to enter the
insulation is something that I don't know.

In any event, this is probably not what is meant by 'work'.
More likely, what somebody wants to know is "Are VBs workable?"
or more precisely, "Will I sweat to death in a VB?" The
short answer is that if you use a VB in the right conditions
you will stay warmer and dryer and you will not stew in your
own sweat.

Anticdotal evidence suggests that is a significant minority
of people who simply are not comfortable in VBs. But judging
from the discussions in rec.backcountry, it is not clear
whether or not this is related to the individual's unique
physiology (as is often claimed) or to his or her's failure
to use the VB correctly (as is often charged).

Regardless, you will be more comfortable using VBs if you
understand their effects on the body's physiology and work
to adjust your insulating layers and activity to prevent
yourself from overheating, which will cause you to sweat
even if the air in the VB is humid.


-------------------------- * -------------------------------

8) When and how should I use VB sleeping bag liners?

Most folks will tell you that VB liners become workable when
the temperatures get pretty low, like down around 0F. That has
certainly been my experience with plastic VB liners.

Others suggest that VB liners aren't worth the hassle on short
trips. My experience with VB liners makes me pretty sympathetic
to this opinion. VB liners are usually just tubes of waterproof
material, with no zipper running down the side. So, getting in
and out of them means that you need to shimmy and squirm. If
your VB sack is crinkly plastic, your tent is small and if your
tentmate is the grumpy type then this may be a concern.

In the Complete Walker III, Colin Fletcher says that he
finds it easier to use a VB liner by only pulling it up
under his arm pits and not up to his neck. This would allow
you to adjust the humidity in the VB by moving it up and
down your torso (which will let moisture move into your
insulation). It would also let you wear a jacket or sweater
*over* the VB.

Still others will argue that VBs allow you to shave ounces
from your sleep system. The argument is that since you
sleep warmer with a VB, you can get by with a lighter
sleeping bag. While this makes sense in theory, my experience
doesn't quite confirm this. I'm of the school of thought
that if you aren't sleeping in all of your clothing at
night, then you carried too much clothing. That is, I assume
that if I hauled a nice warm parka up the mountain I'm
going to put it to good use by wearing it. The problem is
that VB sacks will get every piece of clothing that it inside
of the VB wet. What this means is that I can't wear my nice
warm parka or sweater to bed.

So for me, the question about using a VB liner to save weight
comes down to this. Given the same sleeping bag, which will
keep me warmer: the VB liner or my extra parka? For me, the
answer seems to be that I am warmer if I add the extra clothing.

Now, the ultra-light types may differ from this point of view.
Some ultra-lights devotees forgo the warm sweater or parka
and plan instead on using their sleeping bag to stay warm.
I've seen these types hustling through their camp set up chores
in their trail clothes before they cool off. Later, they
hang around camp with their sleeping bag draped around their
shoulders like a shawl, effectively (or not) replacing the
need for a sweater. If this describes your approach, then
adding a VB liner will boost warmth of your sleep system
for very little weight.

Jack Stephanson and many folks who use his bags will tell you
they can be used in all temperatures, including warm temps,
without discomfort. This is for 2 reasons. First, since the
VB is built into the sleeping bag, the sleeping bag zippers
make is easy to regulate the heat and humidity in the bag - much
more so than what you can do with a VB liner. Another reason
why the Warmlite bag may be more comfortable is due to
Stephenson’s unique Fuzzy Stuff (tm) fabric, which has both a
waterproof barrier and a brushed surface. I can attest from
experience that the Fuzzy Stuff fabric is very comfortable
next to the skin. Unless you are dripping with sweat, the
Fuzzy Stuff fabric feels dry next to the skin.



-------------------------- * -------------------------------

9) When and how should I use VB socks?

VB socks can be worn when you are actively hiking and skiing
with no problem. This will keep your insulating socks and boots
dry from sweat. Common wisdom has it that if you wear VB socks
during the day, you should not have your feet in a VB at night
so that your skin can recover. This advice may be most applicable
to multi-day trips.

I generally use VB socks on any winter over night trip. I find
it allows me to enjoy dry boots in the morning since they
aren't frozen up with sweat. This also frees me from needing
to sleep with my boots. Dry boots left in the cold are still
cold when you put them on but they warm up in a hurry.

I also use VB socks on winter day trips if the temps are
going down into the low teens or single digits (or below).
If find that it keeps my feet warmer since my boots are getting
soaked from sweat from within during the day.

I should mention that I generally use full coverage, rubber
randed gaitors over my leather boots in the winter. I use
Shoe Goo (or its equivalent) to glue the rubber rands to the
boots, which generally keeps my boots dry. I mention this
because the advantages of keeping your socks and boots dry
from sweat by using VBs is entirely negated if you allow your
boots to get wet from the outside.


-------------------------- * -------------------------------

10) When and how should I use VB clothing?

I've seen only a few commercially manufactured VB shirts.
I know that Patagonia in the deep distant past has made them.
And I think that Marmot has made them too, but please don't
quote me on that. Stephenson’s Warmlite still offers VB
shirts made from their unique Fuzzy Stuff (tm) material.
While a bit heavier, it has the advantage of being able
to be worn next to skin comfortably. With the Patagonia
VB shirt I've seen, you would definitely need to wear
a synthetic shirt under it to be comfortable.

I have had pretty good luck with my Warmlite VB shirt.
I will generally pack this shirt before I will pack
the VB liner. I simply find the VB shirt more useful.

First of all, to use a VB liner, you must be assured that
you bag and VB liner alone are warm enough to handle the cold.
With VB clothing, you can always add extra clothing.

Secondly, I need to get up to relieve myself every night
at 4:00 am like clockwork. With a VB liner, this would mean
layering on extra clothing or standing outside in damp skivies!

Finally, with VB clothing, I get the extra warmth and
moisture protection of the VB without being relegated to my
bag. I can wear it under my down jacket while hanging around
camp while others are huddled in their bags. I can also use
the VB shirt to help dry out the fleece that I wear while
hiking.

I normally hike in the winter wearing synthetic underwear, light
fleece and some sort of shell. This combo allows me to deal with
changing conditions and exertion levels fairly well. However,
it also guarantees that I arrive at camp with under layers and
fleece that are damp from sweat or snow or both. As soon as
I get to camp, I put on my VB shirt over my damp under layer and
layer my wet fleece sweater over it. Setting up camp is not heavy
work (I forgo the snow cave scene) and the VB shirt can immediately
start to work as my body cools down from the hike.

Since my body heat outside of the VB is now dry heat, my fleece
top dries dry much faster than with out the VB. Once my fleece is
dry and my body begins to cool further, I then layer my down jacket
over the fleece without the worry that moisture from my hiking
clothes will end up in my down.

Given that a VB shirt is basically a non-breathable
plastic shirt, you may be surprised that rec.backcountry
has seen considerable dispute about whether or not
VB clothing can be used when you are active. Jack Stephanson
claims that you can hike VB shirts in his literature as do
several posters to rec.backcountry. Others vociferously disagree,
claiming that it is just unworkable. I've played around
with this idea a bit. I've had enough success to not
dismiss it outright. But neither have I had enough
experience with it to advocate it. Experiment with it
and let me know!

I have also used VB pants on several occasions. Experience
with scraping frost off of the surface of my bag on several
occasions suggests to me that the groin area pumps out as much
or more moisture as the torso and arm pits do.

I've never seen commercially manufactured VB pants. Instead,
I just used a cheap pair of coated nylon rain pants.


-------------------------- * -------------------------------

11) What about VB-like clothing?

Some folks claim that you don't have to wear full-blown
VB clothing to get some of the benefits. Remember, one
of the claims about VBs is that they can slow down or
stop insensible perspiration by creating a humid micro-climate
near your skin. I've seen this basic argument raised by
different people and different companies over the years.

One of the longest running products for which this claim
has been made (off and on) is the Marmot Dri-Clime Windshirt.

The Arctic and Antarctic adventurer, Will Steger, has made
similar claims about wearing windshirts near the skin as a
way of creating a moist micro-climate near the skin to reduce
insensible perspiration. This claim was made in his book
on his Antarctic crossing and hinted at in the add copy for
a Pertex windshirt/shell that Lands' End briefly produced
with his name attached to it.

Finally, another mention of this approach can be found in
Chris Townsend’s book on Backpacking (I forget the name of
it but it is a great book).

I often use a Pertex windshirt/shell for winter hiking
and xc skiing and have, on occasion, pressed it into service
as an under layer at night, wearing it over a light poly
shirt. I have also used an ultra-light pair of water-proof/
breathable rain pants in the same way. My experience is that
the less breathable the garment is, the more effective it
is at keeping me noticeably warmer. Still, it is an interesting
idea and one that I have not fully enough explored to make
a specific recommendation on.

Copyright 2003 by David Mann

Saprogenic
02-17-2018, 00:45
I really like my RAB vb socks. Work well with my trail runners. Even when it warmed up and my feet felt like they were on fire because they were so warm, my feet were never wet under them.
I also have the warmlite shirt, their fuzzy stuff lining is nice.
A few years ago there was an Alaskan reality show. I know I know, you've probably never heard of an Alaskan reality show ( haha ). There were teams that raced all over the landscape for days. There was a military team, and those brothers who keep winning that big dogsled race. I remember the one tall skinny guy on the show ran around the entire time wearing an RBH vb shirt on. At one point he commented on it, saying how great it was needed such little clothing with the vb shirt.

kestral
02-17-2018, 13:44
Thank you for above post, very informative.

Dogwood
02-17-2018, 14:20
Seth as im understanding it you're not inclined under a higher output activity like hiking to be wearing your VBL's. Your VBL's are solely for sleeping to address breathability of your bivy shell and add some warmth? And, by doing that you think you saved 20 ozs?

Couldn't you have simply went with a more breathable bivy truly saving wt? It seems you're introducing more wt into the system rather than less with the inclusion of VBL sleep wear. I'd better agree with your approach if your VBL layers were doing double and triple duty if you also hiked in them. ???

Dogwood
02-17-2018, 14:27
Seth, have you considered a high end UL/light synthetic bag for some of those long duration cold or wet trips? After it's all hashed out you may find such a synthetic to be a less complex system being lighter wt.

Leo L.
02-17-2018, 15:48
Western Mountaineering sells a vapor barrier sleeping bag liner...

I use an old nylon sleeping bag liner, that looks like a bivvy but is not waterproof, but works a bit like a VBL.
The main purpose is to Keep the bag clean and add a few degrees to the bag in cold nights.
When I use it outside the bag, the bag will be damp in the morning.
When I use it inside the bag, I will feel damp, but the bag will be dry in the morning.

Dogwood
02-18-2018, 00:35
Lot to digest Pinnah. Some good stuff.

sethd513
02-19-2018, 16:52
Seth, have you considered a high end UL/light synthetic bag for some of those long duration cold or wet trips? After it's all hashed out you may find such a synthetic to be a less complex system being lighter wt.

I figured that my weight savings was from not needing a sleeping layer or extra clothing. I use to bring a very heavyweight layer to sleep in, also i was always under the impression I needed an extra layer in winter. Extra fleece extra socks. Now I wear a thin baselayer layer that drys almost instantly during the day with softshell pants and top. It fits over the vbs so everything can be worn together. I have my down pants and coat and hardshell pants and coat. The only way for me to save weight on my trips at this point is to go out when itís warmer. Iím thinking about dumping my spare socks actually because I donít know where else to save weight.

If itís going to be 10-15 degrees out I could bring my 40* quilt, eVENT bivy and vbs with all my winter load out (down pants coat beanie) I havenít weighed my vb suit and probably should. But Iíd assume itís around a pound. Right there that is probably 3 lbs and I wonít be comfortable. Iíll get through the night but might get pretty cold a few hours before I wake up. Could use my 20* and it only adds about 10 oz and should be able to remove the vb suit but Iím sure the bag will be very wet In the morning. Who knows it might be fine. I havenít tried that in the new bivy which breaths very well.

My last trip was 0,-1. I brought my -20 col vb suit and winter load out. Extremely warm. Over heating warm. Vbl, base layer and soft shell pants coat to sleep in. Very comfortable. My wife used the eVENT bivy with her 10+30* quilt. Xtherm with zlite sol on top. It was her first night trying a vb suit. She sleeps very cold so we dropped the temp ratings when we got her stuff. 40 for me 30 for her. Comfortable at 40 sort of thing. The Cuban bottom was all frost. The event literally had no frost on it and her quilts looked great. She said she was so warm she couldnít believe it as her eye lids were all ice.

Our first winter camping trip I had a 30* down mummy bag with a 50* synthetic over bag. It was -6. I literally froze the synthetic bag. Vb suit for me has done a few things. Itís given me a better grasp on how far i can push my gear. It helps me keep my gear dry so if I needed to be out for weeks on end if something bad happened my insulation would be sufficient? On paper so far. Sure for a single overnight you donít need the suit. But for me I like where itís going for me.


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sethd513
02-19-2018, 17:00
I could use my 20+40 quilt with a bivy and vb suit down to probably the same as my -20 col. The quilts and bivy are 15,26 and15 being a total of 56 oz. the col weighs 73oz and I still bring the bivy Incase I got stuck on a ridge. I could layer my quilts and save pounds. I donít feel like it though. Could I layer my quilts with the bivy without the vb and use my -20 col without the vb to the same temperature. I donít know. The quilts look loftier when they are layered then the col but thatís a whole other thing


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Highland Goat
02-23-2018, 08:25
I have an RBH Deigns jacket, but I only wear it in extreme cold (-20į F or below). Your layers underneath will get wet, but if you wear down on top you it will stay dry. I would not wear down for a multi-day winter trek without it.
However, I don’t like that sort of thing for sleeping.