Waterproof spray for Sleeping bag?

**chromedome** · 06-20-2014, 15:46

I was curious if anyone has ever sprayed the back side of their sleeping bag with a silicone type waterproofing spray, like camp dry? The objective being to create an air barrier.

**SilvrSurfr** · 06-20-2014, 16:52

What is an air barrier?

**ntxkayakr** · 06-20-2014, 17:13

I have not done that, but have used silicone sprays for several other applications. On the foot of the sleeping bag may be most effective for condensation, because it is near the edge of the tarp, or rubs the bivy sack if you go to ground.. Also there are several hi-end bags that have "waterproof" breathable fabric especially at the foot box. As you most likely appear to know do not spray on top. The sticky HF articles and threads on Vapor Barriers and related issues are worth reading if you have not do so recently.
However, if I understand your question you may be trying to create an insulation layer of air. Is that your objective? Klymit pads do this to some extent and pack down fairly small, I occasionally combine a 3/4 length Klymit with a mylar space blanket. Minimum condensation problems.

**chromedome** · 06-20-2014, 17:37

My thought was that the spray might make the material like a wind breaker.. eliminating the need for a pad or any under insulation except for the sleeping bag itself. This would be for warmer weather of course.

**pgibson** · 06-20-2014, 17:55

All you would end up doing is reducing breathability in your insulation trapping body moisture/condensation in the insulation reducing it's effectiveness. It won't add extra warmth. If anything you would be cooler. Insulation works by trapped air space. Any insulation that you are laying on top of is reduced in it's effectiveness by compression that reduces that air space. Moisture aka condensation also reduces the functional performance of any insulation. That's why when someone talks about being clammy it's usually combined with "Cold"...cold and clammy.

**chromedome** · 06-20-2014, 20:19

i guess i dont understand how it would be different than having a ccf pad, in or under your sleeping bag?

**f k** · 06-20-2014, 23:24

Originally Posted by chromedome

i guess i dont understand how it would be different than having a ccf pad, in or under your sleeping bag?

Ccf stands for closed cell foam. That means when you lay on it that it does not squeeze out the air pockets that are insulating you. With a sleeping bag the air can be squeezed out when you lay on it causing all the insulation to be lost making the parts you are laying on simply a thermal conductor. Does that make more sense? =)

**nuttysquirrel** · 06-20-2014, 23:51

why not just plastic wrap yourself?

**chromedome** · 08-19-2014, 19:03

I tried this with an older coleman 40 degree sleeping bag. used a whole can of spray on just the back side of the bag. we camped not to far from the lake Mi shoreline, so there was a decent breeze going every night we were there. first night it got down to 41* and i was pretty comfortable. a little warm, but i had a sweat shirt on, once i took that off i was just about right. The second and third night the temps were around 50* I was wearing a t shirt,shorts,and sock, and i was roasting. I used no pad, and had no cold spots at all.

**Flounder** · 08-19-2014, 19:23

Two hikers I hooked up with early on my AT hike in 2013 treated their bags the same way. They bought new bags in Franklin, NC because of condensation issues.