I spent a couple days at the GORE-TEX headquarters last week for a blogger's summit with people who cover gear for traveling, snowboarding, rock climbing, camping, mountain biking, hiking, and more. It was the company's plan to teach us how their stuff works, tell us about a new Experience More social network they're launching, and to bust some myths about breathable and waterproof fabrics. At times it felt like a science class, but one that was actually interesting and useful. Yeah, I got a couple jackets that I'll be reviewing on here later, but I also came back with lots of knowledge I didn't have before.
Here's your mini-lesson in why seeing a Gore-tex label on something matters and how it works.
1) Gore-tex is made from fluoride
This was my first revelation. I always figured it was some kind of petroleum-based plastic product. Instead it's powdered fluoride turned into a membrane made of microscopic threads. Sweat evaporates through the membrane, but water droplets don't get in. Simple concept, but it takes complicated science and manufacturing to create it. (The membrane holes are 700 times larger than a sweat molecule, but 20,000 times smaller than a water droplet.)
2) Gore-tex is meant for cool places, not the tropics
A breathable membrane of any kind won't be much help when you're in the Amazon or zip-lining in Costa Rica. In basic terms, your hot sweat molocules need a cooler place to escape to. That works great when you're skiing or hiking in the mountains. In the hot, humid tropics however, the sweat has nowhere to go. It's just as hot and humid outside as it is around your body. So the sweat just sits there. Technology can't save you there---unless it's the technology in your air-conditioned hotel room. So this is exactly what you want for skiing/snowboarding, hiking, or living in a place like Seattle or Iceland, but not what you want for a boat ride down the Amazon.
3) Gore-tex is just the protective membrane, not the outer fabric
When you see a Gore-tex label on a North Face jacket or a pair of Merrell shoes (or any of these other brands), that's just referring to the waterproof (or windproof) membrane built into the design. It's just one of several layers. The actual waterproofing on the outermost layer is some form of DWR, which brings us to...
4) Waterproof jackets should be dried in a dyer
It sounds counter-intuitive, but hang-drying your waterproof jacket is a bad idea (sorry Europeans!). Over time the waterproof properties of the DWR deteriorate from abrasion, dirt, and oils from your skin. Washing it helps, but then it needs the heat of the dryer to restore and realign the microscopic pegs that repel water.(Obviously this won't work for a rubber raincoat or something with a pure polyurethene coating---check the label.)
5) "Waterproof" is best, "water repellent" is worst
I always assumed "water repellent" was better than "water resistant," but I was wrong. Apparently in outdoor apparel industry terms, resisting something is stronger than repelling it. Go figure. Save yourself the head-scratching and look for something labeled "waterproof."
6) There are lots of sub-categories, but Gore-tex is generally waterproof and Windstopper items are not
The Windstopper products are meant for situations where wind is a bigger factor than rain. These are high-tech windbreakers that keep you warm and eliminate the "wind chill factor." I wore one into Gore's wind testing room (giant fans blasting out really cold air). My upper body felt fine, even though what I was wearing looked like a regular fleece, but my lower body and feet were freezing.
7) "Breathability" measurements don't have an industry standard
"There's no FDA for breathability." Gore was the first to develop breathable fabric (in 1978) and says the most reliable measure of this ability is one put out by the Hohenstein institute, but competing companies use a variety of other measures. Some of these scales are hard to duplicate in different environments and the "as good as Gore-tex" claim is hard to disprove until you're soaking in sweat inside your jacket and it's too late. If you buy jackets, gloves, or shoes with eVent, Pertex, or some other similar technology, you probably won't find them using the same measurement techniques. It doesn't mean they don't work, but there is a good reason Gore products are the ones used by astronauts, firefighters, mountain climbers, and the military.
8 ) Gore tests everything with their name on it and guarantees it
Your jacket may say Arc'teryx and your gloves may say Marmot, but each model with a Gore-tex tag gets tested in their labs to make sure it works properly and will hold up for a lifetime. Why do I have a row of washing machines pictured here? It's because jackets are thrown into 200 of these washing machines and beaten up for weeks on end. If they don't hold up to at least 500 hours of agitating, they fail. There's a rain room to test the waterproofing (I got to stand in it with rain gear on), there's another room that takes the temperature from - 50 degrees celsius to + 50 degrees celcius. The shoe machines pictured at the top continuously flex the shoe in wet conditions for days on end. Glove machines with sensors test whether the temperature is changing when they get wet. Gore hires students to run on a treadmill with their gear on and tests how dry they're staying. This enables them to back up every Gore-tex product for life.
It doesn't matter if your jacket says Burton or Mountain Hardware. If you get wet while wearing it, you can return it to Gore. They've been doing that since 1989. To me, that says a lot.
Search Gore-tex products at Backcountry.com
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