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I’m ignorant of the tech here. But it seems to me that “stopping water coming in” and “letting water get out” is something of a dichotomy. We want, what, a one-way fabric?
Yes. That's exactly what it is. There are two mechanisms at work.
- The original membrane had tiny teeny holes in it as does eVent and some others like Pertex Shield Pro (?). Surface tension stops water drops getting in, but *vapour* gets out - and this is crucial. If you sweat liquid sweat, that isn't going to wriggle its way out of your jacket on its own. You need a tight fitting wicking undergarment aka base layer which will soak up the moisture from your skin and wick it away. It needs to evaporate from the surface of your outermost inner layer so it can then percolate through the fabric.
- Modern GoreTex and most fabrics have a polyurethane layer on the outside of the tiny holes layer. This is hydrophillic on one side and hydrophobic on the other. The inside absorbs water and transports it through, where it evaporates. For this, you need the water to condense on the inside of the jacket so it can soak in and be sucked through.
Two very important things have to happen for this process to work if you're exercising hard in either situation.
1. You must not wear cotton. It will absorb your sweat into the fibres and get wet and soggy, without transporting it to the outside. So you will be wet regardless.
2. The outside of the jacket must not soak up water - this means it needs DWR coating.
If you are not working hard, you aren't making liquid sweat but you are perspiring - you do this all the time. The perspiration leaving your pores evaporates immediately and this can exit the jacket without the aid of a wicking layer. If you're working hard, you need the wicking layer.
In the old days, you could be sitting or standing still in a non breathable jacket and it would still get wet on the inside as all the moisture leaving your body had no choice but to condense.
Not a seam failure, not sweat but just the material could not cope with the amount of rain and cold and started to soak thru.
How do you know? I don't think there's any way to distinguish between condensation on the inside of a jacket and rain getting through from the outisde. When my jacket leaked, it clearly let in cold water after only 5 mins when I wasn't hot and sweaty, it was just a stroll in the rain. After 10 hours on a long walk I'm not sure how you'd know.
I think because we were a bit cold and thus no vapour pressure to push water vapour out and prevent water coming in.
I don't think the membrane relies on vapour pressure to stop water getting in. AIUI it's a one-way process. but the whole wicking process from your skin outwards does need warmth.
because we were not hot enough to be sweating ( borderline hypothermic) and the wetness patterns on the clothing underneath were where the rain hits not where you sweat ie on top of the shoulders etc and the amount of water. Not where sweat would condense either. Its not the first time it has happened either. totally waterproof up til around 6 hours in the rain then started to seep thru. Both of us, both with brand new goretex, more than one occasion. Multilayer wicking fabrics underneath
Edit - its the pressure of the rain forcing water thru the fabric without any vapour pressure going outwards. If you are warm this does not happen
So a very thin layer of clothing kept you dry for 6 hours in pouring rain? That sounds incredible to me, especially since the jacket has large holes in it so you can see where your going etc.
If it had been non breathable like oilskins we would have remained dry. the water was NOT coming in thru the neck or sleeves or front. It was soaking thru the material
Not superthin either - these were winter walking jacket weighing well over half a kilo
That sounds incredible to me, especially since the jacket has large holes in it so you can see where your going etc.
They have things called hoods now...
try this as an experiment. Turn the hood of your breathable jacket inside out. Put a bit of water in it. add a bit of pressure - doesn't need to be much ( or hang it up with a puddle in the hood. watch the water soak thru the material. without the pressure it takes a while. with the pressure its almost instant
I cant' be bothered watching the video, but let me guess - another shallow youtuber discovering stuff that was well known 30 years ago and presenting some great revelations based on limited understanding. Marketing gimmick? if you're 7000+m up a far mountain ridge days from safety with some weather rolling in, what other fabrics would you rather be wearing? At the same time, if you're doing high energy activity of any sort and keeping a waterproof of any sort on as default then you may be missing the point. That said the latest versions of Gore Pro are different and noticeably better in MVTR than what what came before... having been through every iteration since V1... These fabrics have there place and are market leaders for a reason but not every user will need those capabilities and cheaper alternatives are available.
I watched the video and I didn't get upset about it.
I have come to the conclusion over many wet years that an umbrella is the best option if there isn't much wind.
I use an agu poncho on my bike and over my gortex motorcycle gear when it's throwing it down.
IME after several hours of proper rain whilst working hard, you get wet. Breathable/non breathable hood/no hood etc. It wicks up the arms, up from the stomach and seeps in through the hole your face pokes out. I've yet to see a jacket without at least 4 big holes (head, 2x arms, torso) and water finds it's way in that way when you're swishing about.
Dunt matter how many £££'s you spend or how new it is. Dampness beckons here... 🙃
so why were we wettest on the shoulders? I had a wide brimmed waterproof hat on - neck opening was dry
Your jacket is touching your body most on the shoulders perhaps? Also the shoulders collect most of the rain so m8ght be colder (cos the rainwater is cold) which would mean more condensation in the places that are being rained on the most.
MOlgrips - it was soaking thru. try the experiment above. You do not sweat when borderline hypothermic
so why were we wettest on the shoulders?
Carry sacks? Probly sweat condensing under the straps... If no sacks, I dunno. YMMV but I've always got wet in really foul days regardless of the top layer.
endoverend
Full Member
I cant’ be bothered watching the video, but let me guess
Guessing isn't working too well for you
you could see where the rucksac straps were - it was less wet there. Same as we were dry down our backs - because the rucsacs were taking the rain not the back of the jacket. the pattern of wetness made it obvious the material had just got overwhelmed by the pressure of the water. We were not sweating being borderline hypothermic
Seriously try the experiment with a hood full of water - you will be suprised at how easily it comes thru with a wee bit of pressure
Pit zips definetely help release the sweat, though. Would always have them on a bike jacket.
Hydrostatic Head, isn't it? So, 20K is the benchmark for a few hours...I can't imagine any breathable fabric withstanding 6 hrs +
indeed finephilly - thats the issue. being cold inside the jacket makes it happen quicker.
IIRC, Gore Tex works due to the temp gradient (and therefore pressure gradient) with higher temp/pressure inside driving water vapour through the PTFE membrane to the outside.
BITD I was always a bit sceptical of high altitude single skin Gore-Tex tents for that reason as I couldn't see how in UK conditions, I wouldn't be getting wet with stuff coming back through.
"What were you arguing about on Singletrack World today dear?"
"Whether Gore-tex is indeed an effective semi-permeable membrane..."
Hmm. TBF if I was out walking in mega-rain then a wax cotton jacket like a Barbour is probably best.
Seriously try the experiment with a hood full of water
Heh, you forget who you're talking to 🙂 I have done plenty of tests, including filling a jacket with water, and I got nothing - I was doing it inside out though so the water was on the outer face. I've also put on a dry cotton T-shirt under my jacket and stood under a cold shower. I felt cold and wet on my shoulders but the t-shirt revealed nothing although my skin had become somewhat clammy. Of course I wasn't in there for 10 hours but it shows that simple water pressure from falling water droplets isn't enough to get water in through the fabric.
Some other pressure related mechanism perhaps - for example, water under rucksack straps, or sitting on wet ground might create the pressure required to push water through a fabric.
TBF if I was out walking in mega-rain then a wax cotton jacket like a Barbour is probably best.
How breathable or waterproof is waxed cotton? I personally would not wear a Barbour jacket, I'd boil.
Yea, waxed cotton is not very breathable at all. But, it is very waterproof + the jackets are usually insulated. You just look like a bit of a country bumpkin when wearing one...
The other option i've considered is Ventile, which is very tightly weaved cotton. It is supposed to be very breathable and yet waterproof, using the same principles as Goretex. Never tried it though, due to cost.
https://hilltrek.co.uk/about-hilltrek/ventile/
Aye. Add to the recent ‘Experts of STW’ thread: breathable fabric engineers (if there is such a thing).
Probably Chemical Engineers innit? (3M/BASF/Dupont employees) coming up with coatings and/or polymers to laminate together.
There's probably loads of ways to skin the Waterproof and/or Breathable cat from a materials perspective, but for the companies flogging clothing in those markets, half the battle is the punter's perception of your product and the tradenames attached to whatever fabric you use can carry more weight than their actual function...
Beyond jackets I think Shimano's winter boots are a good example of this, specifically the MW7 Vs the MW5.
I'm very happy with my MW5, it takes a fair bit of effort to actually defeat the waterproofing IME and I'm really not sure I believe the MW7 is worth double the money for a Gore-Tex badge and a Boa (Discuss), but I did mull the option of buying the MW7 the allegedly posher materials and my general ignorance of how well they perform, was swaying me a bit (being a bit of a skinflint won out though).
Of course Shimano are probably big enough with a diverse enough product line not to be "afraid" of Gore, and if there's money to be made from sticking their name on the flagship product they'll do it, but as ever the next model down ain't bad despite not using Gore-Tex
Personally I think it does a great job.. I dropped a big lump of cash on a G-tex Pro jacket some years ago, and I've never regretted it, and that jacket has hundreds of days on it now and has seen a lot of wet and windy weather. If you're really hammering out sweat then you'll get wet in most anything, even just a t-shirt
The reason Sympatex died , and eVent gets a beating, and ditto a bunch of other competitors is that they might be fantakka for a fortnight or so, but they soon fail after that. Goretex have had some bum products (XCR for example) but I can't fault Pro or Paclite.
Edit - I've had a ventile jacket years ago. They are nothing like waterproof. Think of it as heritage softshell
'try this as an experiment. Turn the hood of your breathable jacket inside out. Put a bit of water in it. add a bit of pressure – doesn’t need to be much ( or hang it up with a puddle in the hood. watch the water soak thru the material. without the pressure it takes a while. with the pressure its almost instant'
I'm calling bs on this. Tried. After 10 minutes no water came thro', nor did any dampnes suggest it was going to.
Guessing isn’t working too well for you
Alright, I watched it then. It was exactly as I expected. Didn't learn anything. In fact most of it was well known among outdoor types in the late 80's, some of the rest of it was just opinion and not very accurate.
Well it's a long time ago but part of my uni course was to do with semi permeable membranes as applied to fabrics. I then spent a while supervising biomimetics projects with Reading Uni one of which was ways to improve breathability and waterproofness. (Trying to copy what stomata do)
I did happen to watch that last night, not much new (for me) on the stuff about how breathability fails when it's soaked, but I didn't know a lot of the stuff about how Gore operates as a business.
I always think it's a tricky one because lots of things are true at the same time. Is my eVen't jacket breathable? Yes, way head of my old XCR and even further ahead of a non-breathable waterproof. Is it waterproof? Yes - despite what some people are saying above I'm happy that water does not ever make its way through the fabric from the outside, and I'm never going to encounter any conditions where that could happen.
Am I lovely and dry after a few hours walking up hills in the rain? No, I'm not - probably not when it's brand new, and definitely not when it's a few years old and it's been Nikwaxed or whatever a few times. So I guess in that respect you could argue it doesn't work, but I still can't take it seriously when someone says you might as well just wear a bin bag.
I’m calling bs on this. Tried. After 10 minutes no water came thro’, nor did any dampnes suggest it was going to.
did you put any pressure on it? If not it takes hours not minutes to come thru.
The other option i’ve considered is Ventile, which is very tightly weaved cotton
Paramo, isn't it? Looks and feels exactly like a shell suit.
‘try this as an experiment. Turn the hood of your breathable jacket inside out. Put a bit of water in it. add a bit of pressure – doesn’t need to be much ( or hang it up with a puddle in the hood. watch the water soak thru the material. without the pressure it takes a while. with the pressure its almost instant’
I’m calling bs on this. Tried. After 10 minutes no water came thro’, nor did any dampnes suggest it was going to.
My experience exactly. I wonder if TJ is incorrectly washing his jackets or something? What fabric specifically was that? How are you applying pressure in this experiment?
In the case above it was brand new - both of us. Both were goretex 3 layer
Its just the fabric gave up under extreme conditions - torrential rain for 10+ hours. started to seep thru after around 6 hours.
10 mins is not enough time unless you put a bit of pressure on it. It takes hours for this to happen just under gravity
UI know what happened to me in this case. I just dobut many folk are in such conditions for so long that thre capabilities of the fabric are exceeded
I don't think goretex is a gimmick but it does have its limits and one of those I found
No, Ventile is pure cotton and that company do a 2L jacket which is supposedly waterproof. The fibres expand when wet, creating an external barrier.
I think Paramo jackets work by capillary action...
Paramo is a Pertex/Pertex alike outer isn't it? Nikflavourproofed for extra waterproofness? Isn't it the one where you get a bit wet but it's warm so that's alright or was that Buffalo? I hated my Buffalo for anything other than sitting on a belay in a Scottish winter. Actually moving, I was overheating and soaked.
I don’t think goretex is a gimmick but it does have its limits and one of those I found
There are of course lots of versions of Goretex and other similar fabrics with different hydrostatic heads.
Why would water seep through the fabric after 10 hours when it didn't after 1? There would have to be a process at work there.
Wait…How is it that mountain bikers – of all folks, haven’t known this for years?<br /><br />
It occurred to me years ago, jackets that cost me quite a lot of money just stopped keeping the water out. I started doing what I do now, wear a couple of light fleece and windproof tops, with a cheap Peter Storm for the rain. <br />Until work started supplying a hi-viz that was, at least nominally breathable, I wore a Buffalo Special 6 with a Helly Lifa underneath, a work hi-viz vest, and a Peter Storm in the rain. Ten-twelve hour days with rain from beginning to end, and that combo has kept me dry all day every day. <br />A pair of heavy-duty overtrousers complete the ensemble! 😁
ive got some paramo salopettes, they are good and ideal for scottish winter conditions/climbing. You stay dry but if you sit on wet ground you'll get a wet bum as theres no membrane they work by capillary action. They are better nikwaxed but still work just about without it in my experience. These days I think they are surpassed by a goretex/powerstretch combo - lighter, warmer, dryer, unless youve punctured or worn through the membrane. But they are still good, and pretty much indestructable, so they have their place providing the temps about 0c.
I wore a pair of 7 Mesh Thunder Pants (great name, pretty sure that's why I bought them but obviously I am not swayed by marketing) last week at Dyfi. I hadn't realised they were Goretex until i removed them after the first day. I was completely dry on the inside, they worked perfectly. They also worked for half of the following day and then I had a massive off and tore them, they are less waterproof now 🙁 more like Distant Rumble Pants than Thunder Pants
Why would water seep through the fabric after 10 hours when it didn’t after 1? There would have to be a process at work there.
Yes there would be - my guess is that first of all they wet out. Then start to absorb the water then it wicks thru to the inside. Takes hours of continual heavy rain and you have to be cold inside the jacket. Its one of those things where when all the factors line up it happens is my guess. same jacket has kept me perfectly dry in less awful conditions like 4 hours of intermittant rain and I doubt many of us have spent 10+ hours in torrential rain
I have a GoreTex Pro hooded jacket which has been faultless - and that includes 12 hours in heavy rain in very windy conditions.
Were you warm? I think a big part of it was we were both cold so no vapour pressure / heat gradient heading outwards
more like Distant Rumble Pants than Thunder Pants
