Moisture build up in winter sock?

[Marlin]

In my winter mountaineering days we would hang a 9-hour UCO candle lantern near the top of our two-man tent and leave the top of the tent door open overnight for ventilation. The candle seemed to generate enough warm air flow to keep the moist air moving out of the tent before it could condense & freeze. At -20°F and no wind we still got some frost inside, but it was lower down and off to the sides, so there was minimal snowfall inside the tent when you got out of your sleeping bag and started shaking the tent around.

That said, the idea of a candle hanging over me in my winter sock makes me very uncomfortable -- seems like it would be a little too close for comfort and I'd be worried about the sock blowing into the candle if the wind picked up. (Poof! There goes your sock. And your hair. And you might have to roll out of your flaming underquilt. Yikes!) I know there are hangers who like to hang a candle lantern under their tarp (Shug for one), but having one inside the sock sounds almost suicidal. A tealight candle lantern might reduce the risk, but still too scary for me.

Has anybody tried this and lived to tell the tale?

[Shug]

In my winter mountaineering days we would hang a 9-hour UCO candle lantern near the top of our two-man tent and leave the top of the tent door open overnight for ventilation. The candle seemed to generate enough warm air flow to keep the moist air moving out of the tent before it could condense & freeze. At -20°F and no wind we still got some frost inside, but it was lower down and off to the sides, so there was minimal snowfall inside the tent when you got out of your sleeping bag and started shaking the tent around.

That said, the idea of a candle hanging over me in my winter sock makes me very uncomfortable -- seems like it would be a little too close for comfort and I'd be worried about the sock blowing into the candle if the wind picked up. (Poof! There goes your sock. And your hair. And you might have to roll out of your flaming underquilt. Yikes!) I know there are hangers who like to hang a candle lantern under their tarp (Shug for one), but having one inside the sock sounds almost suicidal. A tealight candle lantern might reduce the risk, but still too scary for me.

Has anybody tried this and lived to tell the tale?

I rarely if ever do that...it usually sits on the ground. Might hang it off a tarp line but onece i enter the hammock candle goes on ground. They bounce around too much.
Would never hang one in a sock.
Shug

[Marlin]

I rarely if ever do that...it usually sits on the ground. Might hang it off a tarp line but onece i enter the hammock candle goes on ground. They bounce around too much.
Would never hang one in a sock.
Shug

Thanks, Shug. Guess I misunderstood your candle usage. I've been afraid to hang mine under my tarp because I've been using the smaller tea candle style so all the wax quickly melts into a cup of hot liquid. The total heat is low so I'm not worried about damaging the tarp, but it seems like it's hot wax just waiting to be spilled on a clumsy hanger sleeping below... Even contained in one of the baby food jar candle lanterns like I've been using, it could still dump its entire contents if it got a good whack. My larger UCO candle lantern with the 9-hr spring-loaded candle, though, only melts at the tip below the wick and has never dripped a drop of wax. So that one I wouldn't worry about jostling, but it burns hotter with a bigger flame so it would have to hang too low under the tarp to be practical.

[cougarmeat]

I was going to correct that statement that the WB sock "opens at the top" because the U zipper is on the side. I also thought a sock and tarp would be like a double wall tent and the condensation would form on the underside of the tarp. But in my case, the tarp is too far away from the sock to keep the air between them warm enough. I am playing in about 5 degree weather and had a bit of frost in the sock the first night when the zipper was opened less than 12 inches. The second night I opened it more an only had frost just over my head. I use a balaclava with a nose piece to keep that warm and have been playing with a light (airline) fleece blanket to see how that will work. Dutch has a sock designed like the one Shug's photo - with a bug net just over the head area for better ventilation. But to close it up, you have to reach over your head and cinch up some cord near the gather. I can't reach that far so I may get one and modify it with a zipper opening like the WB sock.

The sock doesn't limit my visibility too much if it is unzipped and you can do that if the closed side is against the wind. But a main feature for me is to block wind/rain that comes in parallel to the tarp, especially if you don't have doors. With Dutch's design, if bugs weren't an issue, I could just pull the sock up to my neck. But if I really needed to use the netting, I need a way to close up the head end that works for me.

I fantasized about using a candle lantern to take the moisture out of the sock, but that top of the lantern has a brass plate that sits just above the flame. Very HOT (don't ask me how I know). I've always had a rule - no fire inside the nylon. No reason to change that rule now.

[BillyBob58]

Agree. We're really talking about degrees of breathability.
Sil-nylon = zero
WP/B material = somewhat breathable
DWR = more breathable
Plain nylon = even more breathable
Nothing at all = the most breathable possible

The way I see it, the trick is to restrict the "breathability" enough to see some benefits (warmer, some rain protection, etc.) but not restrict it so much that the naturally-occurring water vapor we put off is trapped and condenses to liquid form. I'm talking generally about the entire sock as a whole. So some strategic areas could be very waterproof/non-breathable as long as there is enough breathability in total and in the right areas to let water vapor escape. Just need to figure out where those areas are and how big they need to be for "comfort" (which can vary greatly depending on temperature, dew point, wind, and so on).

Even mosquito netting will collect frost from your breath.
That is why proper venting and no hammock net is so important.

WBBB netting -20F @5am overnite test in backyard.

Is anything more breathable than netting, which actually has open spaces between the fibers? It seems to me that if warm vapor hits a surface- or even plain air- that is cold enough it condenses into liquid or frost. Kind of like when you exhale into cold air.

So does this not also make you wonder just how well our breathable quilts actually manage to do in getting any vapor to pass beyond the outer layers of insulation and fabric and keep on going into the air? I mean, when those shells and outer insulation layers get cold enough, don't you think condensation inside the shell is pretty likely? And of course any sock of any material which is inches or feet away from the heat source of our bodies and getting even colder is going to present a real challenge, even with lot's of ventilation. And of course at some point lots of ventilation becomes in effect no sock at all. But a trap hung well above my head and pitched wide open will still get condensed on.

I'm still scratching my head as to how I stayed so dry inside the HHSS over cover at 6F. I guess VB clothing helped. But I feel my breath would be the main source of vapor. So I guess the frost bib combined with a 6" diameter vent hole managed to get er done? Cause we are talking totally dry(far as I could tell) inside a completely closed cover/net, except for the vent hole and the edges. Where the top cover edge meets the hammock edge. These edges are not really closed, just in contact. But there was no frost or moisture on the net or cover or anything else except the frost bib. I have had other nights at similar temps, but with no cover except a tarp well above my body, and the outer shell of my TQ within a foot or so of my face would be soaked.

[OutandBack]

Happy New Year BillyBob,
You make some good points. I do believe 95% of the frozen condensation is from our breath. Traping or diverting is our only option.
When it's really cold I do believe the moisture that comes from our bodies is traped in the down but it such a small amount one would not notice it unless you spent
several days below freezing. Over time this moisture would build up and decrease the downs ability to insulate.

If I was doing a 5-7 day winter camp with temps never getting above 20F I would be doing the full body VB. But IMO for 1-3 nights its more hassle that its worth.