Cowboy Camping Condensation Question

[Zack L]

Here’s the scenario: It’s October in the mountains of Idaho. You get a late start on the trail and just pull out your pad and sleeping bag. You look up at a beautiful clear sky. You know you will wake up with a soaking wet bag. The question is:

Would a splash bivy like a Borah bivy help or hurt?

It seems to me if the temp is near or below freezing the condensation would settle under the bivy and it would be worse? Or is a bivy like that air-permeable enough that the condensation would settle on the outside?

I’m guessing the only solution is putting up a tarp/shelter or using an overbag but I like cowboy camping on nice starry-condensaty nights so here’s to hoping.

[Marcus]

In my experience, nothing beats an Apex over quilt for ~12oz.

 

It gets soaked sometimes but dries so quickly I’m constantly impressed with the utility and versatility of a 50* (2.5osy) apex quilt as both a UL summer bag and winter over quilt.

Also, I find in the dry SW 60+% of condensation comes from insensible perspiration, not external dew. Although sometimes the ground is dewy, many times I have a damp bag with zero signs of external condensation/dew.

[Jerry Adams]

are you saying you did this and your bag got soaked?

I cowboy camp all the time.  I have a DWR nylon fabric on the outside, M50 from thru-hiker, that stuff has a really good DWR.  I routinely get the outside covered with dew or frost but have never noticed that the down inside gets wet.

Sometimes there’ll be a lot of dew in the middle of the night, but when I get up in morning it’s almost all dried off from body heat.

You could try it, like if you were camped next to your car where you had other things, or take extra insulation with you in reserve in case your down gets wet.  If you survived a couple trips with dew that didn’t enter your down then you could not worry about it in the future.

One time, the weather report said it wasn’t going to rain so I left tent behind.  It rained.  The down inside my quilt got wet.  I eventually got it dried without dying or anything.  For rain you need a tent or WPB fabric.  But WPB fabric is heavy and not very breathable.

Sometimes, my quilt will be quite wet on the outside in the morning and I say to myself that it would be better if I had put my tent up.

If it’s colder, the night sky is clear, and/or high humidity there will be more dew.

I wonder if the M50 has flourine DWR.  That is now verboten.  So as soon as he sells out, there won’t be any more.

[Zack L]

Thanks for the feedback. Yes that has happened to me, with Western Mountaineering MF fabric. If I remember correctly the fabric did a good job keeping the moisture on the exterior, but I could only wipe so much off before packing it so I needed to dry out the bag later in the day.

 

On a similar topic. Has anyone had experience with Alpha Direct overbags compared to Apex? I like the idea of how much smaller they pack and how durable they are, but it seems like the material may be too thin and the dew point would still be around the sleeping bag?

[Jerry Adams]

“If I remember correctly the fabric did a good job keeping the moisture on the exterior, but I could only wipe so much off before packing it so I needed to dry out the bag later in the day.”

maybe bring a cloth to more completely wipe off any water?

if you put something over your quilt, then that something will be wet and you’ll have the same problem

I wipe mine off as best possible and set out to dry.  If I want to leave before it’s dry, I’ll just fold it over so the wet parts are facing each other, then when I set it up again I’ll try to finish drying.  And if it doesn’t condense on it, body heat will dry it off the next night.

Sometimes I just set up the tent to avoid the problem.  Of course, then the tent will get wet with condensation, but I’ll put it in a plastic bag so it doesn’t get anything else wet

Sleeping under trees will usually avoid condensation

I have noticed that some fabrics accumulate condensation more than others.  Like, I think shiny nylon has more condensation, supplex has less.  But I haven’t explored this completely – tried different fabrics and compared.  One more science project…

[Alex H]

So many factors to consider with cowboy camping and condensation but in general either a bivy with more mesh or one with an event top.  I wrote this years ago but it still all applies The Bivy Condensation Conundrum

[George H]

To your question, Zack: I have an Alpha overbag that I use a lot. Used to have an Apex overbag. I don’t use the bivy/tarp combo; either I’m in a tent or cowboy camping with the overbag. And yes, the varieties of Borah style splash bivies I’ve used can easily create condensation issues.

I prefer the Alpha over Apex by a long shot: Works equally well for cowboy camping, all theories of dew point placement be damned; less bulky and easy to pack; no deterioration from stuffing and sleeping on; lighter; quicker drying.

[Zack L]

thanks everyone. Also George which Alpha overbag do you have? I’ve been trying to order a Nunatak but I missed the last open order by a few hours and they don’t have another run until October

[George H]

I made my own – 90 gsm alpha and argon 67 both from Dutch. Pretty simple project

Timmermade have some too. I emailed Nunatak and think they will be open to make these in the late spring

[Matt Dirksen]

Alex, thanks for sharing a link to your article! I was going to look around and share a link to it because I found it to be so inciteful.

I do want to offer one technique that I’ve enjoyed deploying over the years:  using a silk mummy liner OVER my quilt. I have used this system for several years now, and I am amazed at silk’s ability to soak up rogue condensation, whether it’s under a tarp or out in the open.

And it’s a lot easier to dry out than my quilt.

While silk is considered primarily hydrophobic, it has hydrophilic properties (like wool), which allows it to wick up about 30 percent of its weight in water without feeling damp.

Sometimes, it’s not about as much about trying to “repel” the water but more about best managing its inevitability.

[Alan W]

Interesting about a silk outer.

I have no experience using silk like this — or Nylon. Just Wondering —–

Silk is a natural (silkworm) polyamide polymer.  It chemisorbs water mainly at the amide bonds, just like synthetic Nylons

Without a DWR or waterproof coatings, plain silk will reach its maximum equilibrium water uptake more readily than coated synthetic Nylons.

I wonder if a similar weight of untreated (uncoated) Nylon overbag is likely to work similarly to silk.

[Author]

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