Condensation in a Gortex Bivy Bag???

[T3-OleMan]

ADDED: This is an EMERGENCY forced stay 5 miles in, on the Mt., till EMS arrives....GOD forbid....not a camp. {in 1998 broke a leg on way out to get another weeks supplys-walked 3 miles to truck-drove 25 mi to town-got cast & crutches -drove back-called my 2 sons and they packed our stuff out and we went home safely.} I'm upgrading my survival plans, incase I have the Fred G.Sanford. BIG one! LOL!
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Just in case I "FALL & I CAN'T GET UP" (I'm older than dirt-here comes 70) while I am 10,000 to 11,000 ft ELK hunting this (my 18th )year I will be packing a Mil. Camo-GORTEX $125 Bivy Bag and a $20 Fleece cabelas sleeping bag. Now I'll already have punched my little 911 button, but my fat *** could freeze before they get to me.

Here is where I need the help. Got in the Bivy-Zipped it up in the house and in 3 min I was sweating.




I'm not camping on the Mt., But I might be staying on the Mt. One night and I want to know how to keep all my clothes on -including a down jacket- and what sequence I should use these items so next morning My Hunting clothes are dry, not soaked with Condensation.

1. Fleece Sleeping bag- shake the moisture out next morning and pack it.
2. Gortex Bivy bag
3. Space blanket and tri-angle space tent
4. Butchering tarp-string a line for roof support

Could be 5 or 10 below ZERO in November if ~n ElNino puffs through. Just don't want to freeze to death cause I used the items in a wrong SEQ., and got soaked with sweat! I don't think I can zip the Bivy and keep my clothes dry, but thats why I paid $125 for GORTEX. Dadgummit, Can't HAVE NOTHING!
This would be the night from HELL.

Any and all live world experiences welcome...+ … any second hand truths!



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It just dawned on me @ 12:57 as I post this Ding, Ding, Ding-put my Frogg Toggs on, then get in the fleece! Think it will work? Still need the Seq. thingieeeee.

 

[elkoholic72]

I sleep in a Northface Cat's Meow bag with a Slumberjack gortex shell all the
time without any sweat issues. What gets you wet inside your bag/shell combo
is your breath when you have everything zipped up tight. I figured that out the hard way on top of the Beartooth mountains on a 15 degree night. I woke up very damp. My shell has a delrin
plastic rod that goes over your head to make a little tent area. I always keep
a couple inches of the shell open now to let moist air from breathing a way to escape.
Ben.

 

[midnightmalloy]

I sleep in a Northface Cat's Meow bag with a Slumberjack gortex shell all the
time without any sweat issues. What gets you wet inside your bag/shell combo
is your breath when you have everything zipped up tight. I figured that out the hard way on top of the Beartooth mountains on a 15 degree night. I woke up very damp. My shell has a delrin
plastic rod that goes over your head to make a little tent area. I always keep
a couple inches of the shell open now to let moist air from breathing a way to escape.
Ben.

Exactly right. Slept in my slumberjack bivy many times and your breath is the problem. Have a small tarp or poncho with you and make a mini tent over your head. Works great. And actually the bivi keeps you warmer than u think. If you wanna be super comfy get a synthetic down pair of pants, super light and compact and worth their weight ( maybe 5 oz) and good to throw under your outer shell if on stand or glassing in cold weather along with using if needed for an overnight. Like sleeping bag pants essentially.

 

[tt35]

Goretex won't keep you from sweating if you're too warm for the conditions--it just lets a certain amount of the moisture escape once it's prodouced. If you may need to survive subzero cold, it's probably good that you generated a sweat in the living room. Layer your clothes and gear according to the temps you're encountering. If you just sweat a lot or very easily, it may be better to look into one of the permeable fabrics with better breathabilty like E-vent for your bivi sack.

 

[jmden]

Gore-tex is very easily 'overpowered' in terms of how much water vapor it can move through it.

That is why jackets, for instance, made with fabrics with gore-tex or other waterproof/breathable (w/b) laminates include 'pit zips'. Opening up these big zippers under your arms help you eliminate body vapor/moisture. Gore-tex works well as long as you aren't overheating enough to overpower its ability to transport watervapor through the membrane.

The newer generation of Gore-tex XCR was made about 25% more breathable than the older version to help with this issue, but it is still easily overpowered if you work much at all. Just depends on how hard you are working/perhaps what kind of shape you are in vs. the ambient temp/wind/etc. If it's hot outside and you get in the bivvy, you will likely be quickly releasing more watervapor than the bivvy sac can transport.

Many find Gore-tex too waterproof and not breathable enough when it's ability to breath is placed on a continuum from completely waterproof on one end to completely breathable on the other. Many manufacturers have gone seeking more breathable alternatives to keep their customers more comfortable. But, it is typically a pretty reasonable w/b laminate to use in a bivvy sac as you typically aren't running up the mountain while in a bivvy sac. Just very dependent on conditions as too how well it will 'perform'.