Sleeping bags outer fabrics. Gore winds topper vs Pertex

I’ve had at least one WM Gore Windstopper bag I can think of, and have had several Goretex bags from WM and Marmot from the very early 80’s and 90’s. The original Goretex was a bad idea, but the Windstopper is really great, and would be my first choice on a winter bag. It really helps protect from tent condensation falling on the bag and wetting.

On a truly cold winter trip for extended days, I still would carry a VBL. It’s surprising how much moisture will collect in the outer layers of a down (or any) sleeping bag, freezing there and reducing loft and ultimately warmth. BTDT.

Maybe with Goretex you can get condensation on the inside surface?  More breathable Pertex could be better?  Pertex is water resistant enough for rain splash or condensation on the outside?  Pertex is definitely not waterproof enough for rain drops falling onto it, that’s where you need Goretex.

I’m not arguing Goretex is wrong, just that it’s unclear

Maybe with Goretex you can get condensation on the inside surface?  More breathable Pertex could be better?  Pertex is water resistant enough for rain splash or condensation on the outside?  Pertex is definitely not waterproof enough for rain drops falling onto it, that’s where you need Goretex.

I’m not arguing Goretex is wrong, just that it’s unclear

The shell is not “Goretex” per se, it’s Windstopper Goretex, nothing at all like regular Goretex. It breathes VERY well, because it’s not “waterproof” like other Gore fabrics/lamination’s.

Up until the early 90’s makers used standard goretex on bags, but it hasn’t been used in probably 25 years. Last one I got was from WM in 1992. My first was from Marmot in 1982. Regular Goretex didn’t breathe well, and skin and hair oils in the hood area caused delamination (Gore replaced my Goretex WM bag with a Windstopper bag for free under warranty because of hood delamination). Those reasons were why Gore developed Windstopper. It works, adds warmth, water repellency, and wind repellency, and doesn’t delaminate.

The reason down bags lose their loft in extreme cold is because the body’s vapors freeze as they reach the outer regions of the insulation (the cold is “driving into” the outer layers of the bag). As I pointed out, it’s a problem is REAL cold (below zero). Any bag, no matter its shell, will have this issue. Use a VBL. It will add warmth, allowing you to use a lighter bag, and will help keep your bags loft, and therefore insulation, intact. Ditto a Windstopper shell, just from the other direction, outward in.

No, the benefits of Windstopper are many. The negatives are cost and weight… but my experience leads me to believe the benefits outweigh the negatives.

that makes sense

note that pertex endurance is different from say pertex quantum … the former is very water resistant but can delaminate (do a search for it)

that said for cold temps an synth overbag generally works well … not only is the moisture pushed to the synth, but any exterior moisture falls on the synth as well … arctic/antarctic explorers use em

of course the downside is more weight and bulk

the upside is that you can use it as a summer quilt

;)

Does anyone know the vapor permanence of Windstopper vs. Pertex? IMHO, whichever fabric is more permeable, then I’d personally lean toward that, all other things being equal.

Regarding Gore: I still use a North Face 0d bag with Gore’s “Dryloft” membrane on it (which was developed somewhat in tandem with Windstopper back in the 90’s), and I have never experienced any condensation issues on the inside of it whatsoever. Windstoper was originally developed for garmets, and helped introduce the first generation of windproof fleeces to the market in around ’94/’95.

But nowadays I always use a Downtek (or Apex) overbag in order to push the dew point further outside of my system, so my internal quilt is never compromised. If I am in a shelter, then my bag/quilt system should always be as permeable as absolutely possible. If I am every worried about condensation/splash, a highly wick-able silk liner on the outside of my quilt has worked marvelously – but probably only for 0 to 30 degree nights. I’ve never used a VBL before, and not sure if the opportunity will ever truly present itself. Having kayaked in a drysuit on several occasions, I’m not a fan of that squirmy “dank” sensation. While I respect those who use (and get used to) them, I don’t think I might ever get a good night’s sleep inside a VBL.

In order to sleep well, one should pay as much attention to humidity as to temperature. A tiny bit cold with a lot of humidity could be devastating.

Matt

In the past I’ve tried to find something definitive re. Pertex Shield vs. GWS and wasn’t successful.  They’re both probably about the same – not super helpful to the OP, I admit, but more interesting to me is the difference between “mostly waterproof” fabric (Pertex Shield/GWS) and “water resistant”  fabric (Schoeller NanoSphere/MF) (again, not helpful to the OP, but…).  On this topic too I couldn’t find anything definitive.  A lot of what I did find was comments from people who owned one or the other and would say, “It’s work great for me, I’d buy a sleeping bag with x fabric again in a heartbeat.”  Like a lot of high end stuff in life, few of us own or more of them at a time so it’s hard to get comparisons – bicycles are like this too, by the way, few have a stable that they really ride hard and find meaningful differences that would warrant a recommendation.

I’ve noted that WM Bison only comes in GWS and all FF below 10 degree F similarly only come in “mostly waterproof” fabric.  Meaningful? On the other hand, WM offers most of their bags in MF; if GWS was hands down superior, would they do that? I don’t think there’s a clear answer simply because it depends on conditions and how it’s used.

One last thing:  if you’re getting liquid condensation falling onto a winter bag, something seems off. Frozen condensation onto a winter bag, that stays frozen, shouldn’t be a problem for any kind of sleeping bag material. External moisture seems a bit of a canard, and, like others have said above, it’s moisture that comes from the person in the bag that’s the real challenge for a sleeping bag – to manage and to its performance.

As to water coming from the outside, there are “shoulder” temps where it can happen on winter trips (condensation on a balmy night where the temp is altered by the warmer tent interior temp) , but mostly I think in terms of sitting in one’s bag eating and drinking (spills) on a long winter night. I always cook and eat in my bag on winter trips.

Matt, in -20F you’d be happy on a long trip with a VBL… when you wear synthetic long underwear in the bag (which I always do), it’s not at all like being in a diving suit.

Eric, you’re right about a synthetic overbag. I have an old Chouinard/Montbell “Zero Point” overbag that I still use. It’s a terrific piece of gear, and does, in fact, work exactly as you describe. A VBL, however, is lighter and more compact. But a VBL and overbag will genuinely extend a -10*F bag to a -25*f bag.

I still like Gore’s Windstopper.

Hello and thanks all for helping . Yes, I know it is not an easy question to help with, but so far I have learned a lot about different fabrics and its use. Good.

Brad, thanks for helping me, some really good points you had, grouted vs wind stopper explained.  Waterproof and water resistant materials.

Brian, yes lol, you made things worse. But, you did help a lot!

Thank you.

As you say, Wm offers most bags in MF, why? I wonder.

Maybe we will never have a clear “winner”, comes down to users, situations and so.

Hmm, I have to do some thinking. Maybe no need for the extra weight of the GWS bags.

As you say, Wm offers most bags in MF, why? I wonder.

About 12 years back when WM started offering their light series of bags with the gossamer “Extremelite” shells I talked to the owner about them. He’s wasn’t a big believer, feeling, at the time, that the UL craze was a bit misguided driving makers like him in directions they didn’t want to go. I suspect some of the Co.’s philosophy is still that way given the amount of microfiber shells offered. Microfiber is absolutely a superior shell for wind resistance, water resistance, and longevity compared to most of what goes on down bags today, including WM’s Extremelite bags. And yes, in our house, we have an Alpenlite, Versalite and Superlite.

But I carried a 65lb pack on the AT in 1977…

One other thing occurred to me. A couple of years ago I was curious what guided mountaineering outfits recommend to their clients. Fortunately many post really specific gear lists on their websites. In many/all? they specifically required a down bag with “waterproof” shell. Is that just to cover their bases in case of a warm spell or do they know something?

“As to water coming from the outside, there are “shoulder” temps where it can happen on winter trips (condensation on a balmy night where the temp is altered by the warmer tent interior temp) , but mostly I think in terms of sitting in one’s bag eating and drinking (spills) on a long winter night. I always cook and eat in my bag on winter trips.”

Brad, thank you for the tip/information. I do the same, eat, cook and so in my bag.

one thing about coastal snow is that it gets EVERYWHERE … especially when its windy

it sticks to everything … and eventually itll get into your tent, perhaps even your bag … not to mention that eventually your breath in a double walled tent will condense and freeze on the inner falls … and itll start “snowing” inside the tent, especially if you need to button the tent up

also remember that many of these WPB bags were meant for fast and light alpinists … who often bivy as well

;)

Thanks for the reply.

Same here with the snow to..ahhhh

Just as the rest of us, I like to stay dry, warm and sleep good.

WPB bags or not, I do not like to carry more than I need to, but at the same time, I like to carry some thing that give me that good night sleep.

faced a similar decision fall 2015. went with FF Eider EX…could not be happier.

i like Pertex Shield better than GWS in other layers, and after talking with the guys at FF (call or drop by in Seattle, they are fantastic) and hearing their explanation for using Pertex, any lingering doubts i had about its sleeping bag application were resolved.

i winter camp a lot. winter 15/16 in Jersey, NY, VT, NH, ME (really humid) without issue, and this past winter back home in the PNW, again without issue. i use a merino liner, sometimes merino base layers, and had no issues with moisture. fabric shed water beautifully, including one morning waking up to a small puddle of water just chillin between my ankles.

if you are on the fence, consider two features on the Eider that the Lynx does not have: continuous baffling so you can move down from your back to front and EX facing that prevents breath from condensing on your collar (totally works, at least compared to the Schoeller Nanosphere on my FF Raven). i really hated waking up with condensed breath in my face…never again.

Both fabrics typed test ~2.5 CFM and so the permeance is ~ equivalent. The WS is heavier but has a much higher HH do to more numerous smaller pores.

If you want to spend more money, you could always go for a PHD bag with a HS2 shell. Completely waterproof, apparently. The Hispar 600 or 800 K sound like they would roughly fit your criteria, and would be lighter too. You could always design your own on their website too. The downside being you may never have enough money to even leave the house again…

WS in itself is actually waterproof (in essence it’s 1st-gen GTX).

The CFM of 2,5 for WS surprises me as Gore states that something is windproof as long as the CFM is ± 1 or less.

So Gore Windstopper is highly windproof but far more water resistant, even close to “waterproof.”

Like I’ve said, I had both original Goretex bags and a Windstopper bag. The Windstopper breathed noticeably better. Hard to see how the WS isn’t a spectacular choice. Really, as far as I’m concerned, the only real use for WS is as a covering for down/insulated garments and sleeping bags. Trying to draw a conclusion about it based on any other use may lead one to a different conclusion about its efficacy.

Really good thread…

Hello and thanks all for replying.

Jared h, thanks for some good points and first hand experience with FF. I will give them and WM a call next week.

Brad, thanks for helping.  But as you say, hard to pick a winner….if there is one.

For all intents Windstopper is basically weatherproof but doesn’t get too muggy. Less chance of 2nd guessing your purchase in the field with Windstopper.

Thanks.