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Iceman
2006-02-19, 10:55
Evapoventicondenrespiperspitransporation; (I have been working on this one for a bit, so please bear with me.) Evapoventicondenrespiperspitransporation is the point at which the .75 to 1.5liter of perspiration, the .5 liter of respiration transport thru your sleeping bag and condensate at, within or on any given insulative material. For the porposes of this discussion, affected by ventilation, Evapoventicondenrespiperspitransporation is the exact point at which moisture vapors condensate on or in your sleeping bag reducing it's insulative value and causing a moist bag. (Don't even try to abbreviate this as I have found it is impossible, and, besides we all need the exercise.)

Please remember, it is important to consider Evapoventicondenrespiperspitransporation when purchasing a sleeping bag, or selecting a sleeping bag for any given trip. In mild or warm conditions, too warm of a sleeping bag causes the sleeper to get a clammy / sweaty feeling inside of the bag. This example illustrates the importance of considering Evapoventicondenrespiperspitransporation, because (as in this example) the Evapoventicondenrespiperspitransporation point is next to the skin of the sleeper. No evaporative-cooling effect is felt by the sleeper until the bag is opened allowing ventilation of said vapors, and thus moving the Evapoventicondenrespiperspitransporation point to a place further from the skin of the sleeper. The Evapoventicondenrespiperspitransporation point has now been moved from the sleeper, to a point further into the insulative materials of the bag, possibly even completely thru and off of the sleeping bag. Moisture in this case can sometimes be seen condensating on other surfaces of the tent, bivy or hammock, or not at all.

In colder conditions, Evapoventicondenrespiperspitransporation can be noted at the surface of a sleeping bag. The vapors associated with a sleeping human are found to appear either on the surface of the sleeping bag, or at some (Evapoventicondenrespiperspitransporation) point within the layer of insulation. This in essence is Evapoventicondenrespiperspitransporation. When we pick the proper sleeping bag for colder conditions, we should consider Evapoventicondenrespiperspitransporation so that Evapoventicondenrespiperspitransporation occurs at the proper location. Too cold of a bag and the sleeper is uncomfortably cold, and may become, well... a "non-sleeper". Too warm of a bag and, um, .................................................. ......................., I am sure there was a reason not to have too warm of a bag for cold conditions, but I cannot seem to remember what it was right now. More on this later. A sleeping bag which is warm enough for cold conditions may place the Evapoventicondenrespiperspitransporation at the surface of the bag. This can be seen as moisture droplets or ice crystals on the surface. This is actually optimal, in this case the Evapoventicondenrespiperspitransporation allows for the owner of said bag to allow the bags surface to dry. By hanging the sleeping bag out in the sun for a short while, all moisture which had accumulated on the surface due to Evapoventicondenrespiperspitransporation can naturally evaporate and dry. In frigid conditions, the bag can be simply shaken and brushed off, as the ice crystals will simply fall off. Worse is the condition (now I remember) where the sleeper has way too warm of a sleeping bag for the cold conditions that they are experiencing. In this case, Evapoventicondenrespiperspitransporation occurs at mid layer of the given insulative thickness. Moisture here which condensates in the middle of insulative layer is difficult to dry while in the field. Moisture accumulated at this level causes the bag to lose insulative properties, and to gain weight, although slight.

As we can see, proper sleeping bag choices are truly impossible without consideration for Evapoventicondenrespiperspitransporation. It should be considered fool hardy and dangersous to even consider sleeping in a sleeping bag without a thorough study of Evapoventicondenrespiperspitransporation.

One variable which was left out of this discussion which dramatically alters Evapoventicondenrespiperspitransporation is noted below.

If you pee your sleeping bag, and then all bets are off.

Stay tuned for squishysockblisterpop.

Salvelinus
2006-02-19, 19:03
After reading that, I'm tired. I'm going to bed now. I can't figure out, though, do I want to be warm or not? ;)

Funny stuff, Iceman. :)

Iceman
2006-05-09, 00:13
In the last three weeks I have slept in my tent and sleeping bag four nights. Three of the nights were below freezing. The fourth was warmer, about 40 degrees. Of these nights in my bag, the three which were below freezing, resulted in moiture condensating on the surface of my sleeping bag. The warmer night out resulted in no noticable condensation on the surface in the morning. The nights were spentin a tent at 2000' elevation, on solid yet damp or frozen soil, during Turkey hunting trips. Most of my hunting is during cold weather, usually below freezing at night. During both my Deer hunt (7 days) and my Elk hunt (7 days) my bag begins to retain moisture from the prolonged repeat use at below freezing. I think it is time to try a vapor barrier. I intend to start a thread about vapor barriers.

This Evapoventicondenrespiperspitransporation is starting to get to me.

Just Jeff
2006-05-09, 01:14
Wow. You deserve an award for that.

peter_pan
2006-05-09, 09:27
Iceman to star in remake of Mary Poppins.....

Sereously, Nice job...bottom line....don't carry/use more bad than you need for the expected temp range.....or....over time you'll carry more weight in your bag as ice...BTW... an iditarod racer without a VB had a 50 pound + bag at the end of the "I" a few years back....a most extreme example.

Also when warm, learn to vent.

Pan

Iceman
2006-05-09, 09:43
Iceman to star in remake of Mary Poppins.....Pan

I think I am going to need a bigger umbrella.

Iceman
2006-06-02, 23:12
Spent three nights in my bag over the Memorial Holiday Weekend. My Evapoventicondenrespiperspitransporation rate was perfect. The bag I brought was just warm enough so that all moisture considerations were perfect. Moisture travelled thru my insulative layer, and condensed upon my tent walls nearby my sleeping mass. The increased level of alcohol in my bloodstream did not seem to affect my evapoventicondenrespiperspitransporation rate! This is one factor I did not originally include in my previous observations and study. I may have to experiment by placing larger and larger amounts of alcohol in my blood stream in order to fully understand the relationship between alcohol and evapoventicondenrespiperspitransporation. My thought is that as the blood alcohol percentage increases, so does the the chance that evapoventicondenrespiperspitransporation rates just won't matter. Heck, if taken to the extreme, if sputum, vomit and bed wetting are to occur (inevitably) it just wont matter what your evapoventicondenrespiperspitransporation rate is. :dancing2:

Frolicking Dino
2006-06-03, 08:32
Interesting thesis. Have to wonder if providing enough ventilation for the droplets to evaporate instead of form on the surface at temp near freezing wouldn't result in warmer sleep. My thought is that moisture on top likely means moisture within as well - and moisture fills the tiny air spaces making insulation less effective.

Iceman
2006-10-05, 01:11
OK, just received a package today containing my new Vapor Barrier Liner for my bag. After playing around the living room in the liner, I have made an observation. Not real roomy. I bought this campmor vapor liner $24.99;

http://www.campmor.com/webapp/wcs/stores/servlet/ProductDisplay?productId=7646&memberId=12500226&storeId=226&catalogId=40000000226&langId=-1

I have two weeks of hunting coming up starting October 13th for one week, and November 3rd for one week. Weather permitting I will try out this liner and report back on what I find. Last year during the extended trip, with many nights below freezing, I noticed that my evapoventicondenrespiperspitransporation point was at the outer layer of the bag, causing moisture to wet the surface of the bag. We will see if this vapor liner is all it is cracked up to be. Unless I go into an epileptic fit of sorts in the middle of the night trying to get out of the damned thing! Might be a bit roomier if I wasn't so studly.

Just Jeff
2006-10-05, 01:52
Well, at least if you pee in your VBL the insulation will still be ok. Don't know about the evapoventicondenrespiperspitransporation, though.

bird dog
2006-10-05, 02:23
Iceman, say your new word three times while holding your tongue! :aetsch:
BD

bird dog
2006-10-05, 02:28
My younger brother has been diagnosed by a doctor (Im sure of questionable character) with a "medical" condition of overactive armpit sweat glands. He has some fancy name for it, and suckered my brother into buying some special deodarant that smells like burnt metal and costs like fifty bucks.

Iceman, could this be a reasonable variable that should considered with evapoventicondenrespiperspittransporation?

It is a valid scientific question.

BD

Iceman
2006-10-05, 09:45
Well, at least if you pee in your VBL the insulation will still be ok. Don't know about the evapoventicondenrespiperspitransporation, though.

Don't scuba divers just pee in their wet suit? Actually, I stopped wetting the bed last year, so it shouldn't be a problem.

BirdDog, I will have to think on this, get back with it later. Must think...

Iceman
2006-11-14, 10:13
OK, returned last week from my Elk Hunt. Temps at night in the high 40's and wet, wet, wet... Too humid and too warm to try the vapor liner. I will now have to wait for one of my upcoming backcountry snowshoeing overnighter trips to try out the liner. I have a solo cougar hunting trip planned to St Helens in December, should be a nice and frozen then...

Birddog, for your brother with the overactive sweat glands, I would get him a good hooker. This will get him over the nervous sweaty condition. :biggrin:

bird dog
2006-11-15, 00:50
Birddog, for your brother with the overactive sweat glands, I would get him a good hooker. This will get him over the nervous sweaty condition. :biggrin:

He would probably find a way to mess that up and Id be out my twenty bucks. So, he will just have to deal with the sweaty pits and carry the extra weight of his "special deodarant" on our trips. Although, after Linville Gorge, he swore to never hike again. BD

dropkick
2006-11-15, 01:48
Birddog, for your brother with the overactive sweat glands, I would get him a good hooker. This will get him over the nervous sweaty condition. He would probably find a way to mess that up and Id be out my twenty bucks. So, he will just have to deal with the sweaty pits and carry the extra weight of his "special deodarant" on our trips. Although, after Linville Gorge, he swore to never hike again. BD
20 bucks?? Either the prices I used to have quoted to me have dropped drastically or you need to find a better class of hooker.


I, myself, only know the cost as I was often propositioned when I was military. I never partook of the soiled doves, as I am too chaste and pure :angel:

Iceman
2007-11-10, 09:50
Just got back from 8 nights of sleeping with the elk. Spike camp at elevation for two nights, way too cool of a bag, had to sleep in my clothes to keep warm, no elk shot. Last 6 nights at slightly lower elevation in a warmer bag, too warm, very humid, one elk shot. The higher elevation/cooler conditions/smaller tent and lighter bag resulted in less condensation than did the warmer bag/bigger tent at lower elevation. Not sure if this is due to running a bit dehydrated on the spike camp, elevation, tent design, or having a dead elk in camp. Evapovanticondenrespiperspitransporation continues to haunt my thoughts. When will the insanity end?

Turk
2007-11-10, 11:49
I don't know... but when you figure it out, you let us all know.

I am having a heck of a time with this issue and one of my insulated
hammocks I am hoping to keep my daughter warm in this winter.

pure_mahem
2007-11-10, 19:33
Wouldn't the vapor barrier keep all the vapor inside it hence making you a slimy mess inside it even though the bag would be dry? Just a thought.

Iceman
2007-11-11, 20:31
Yes, but the liner keeps your skin at proper humidity, your body stops pumping out so much water, your bag is dryer, warmer. Shame on me, but I have yet to try the liner, should have tried it last winter, our snow camp got down to 5 degrees in the tent.

Very irritating this hunt season, many consecutive nights in the bag, and as the hunt goes on, you notice a damp bag after a few days, expecially near where your respiration accumulates around your head and mouth. I had to take a gas lantern, and hold it close to the material until dry. This took a while, but was worth the effort.

Turk, my daughter and son really enjoy the winter campouts, I have Kelty -40 bags for them, sleep them both on doubled foam wallyworld pads, they sleep very soundly. I on the other hand, worry about them so much and check on them I usually get lousy sleep.

Take-a-knee
2007-11-11, 20:38
Wouldn't the vapor barrier keep all the vapor inside it hence making you a slimy mess inside it even though the bag would be dry? Just a thought.

Maybe yes, maybe no. Some people stop (or markedly slow) sweating once the microclimate next to their skin reaches a high level of humidity. A GI vapor barrier boot is a good example of this. At 40 below, some guys feet stayed relatively dry (only moist), some guys would pour sweat out of their's after a road march. At ten below (F) everybody poured sweat out of their's after a good hump. I've only used a vapor barrier in a sleeping bag a few times and I had good results with it. YMMV. What sucks about it is you can't wear much if anything in the way of clothing, and if it is minus ten you dread crawling out of that moist warm environment 'cause you know it's gonna be painful.

Iceman
2007-11-12, 09:42
Good point. I have always wondered about the feeling of getting stuck in the bag, afraid to hop out and get dressed..... I read somewhere that some climbers wear their poly thermals into the bag, to keep their skin off the barrier. I could see doing this; as the microfiber thermals we wear to bed move the moisture off our skin....

Seems like you would really need a warm bag to benefit from the liner. If too cold of a bag where you really need to wear some clothing into the bag to stay warm, cancels the chance of using the liner.

Just Jeff
2008-01-05, 10:26
Warmlite.com make VB clothing with fuzzy liner built in...you could sleep in that, then keep wearing it when you get out of your bag. Once you're up and moving, and need to control your temp, take parts of it off.