12:27 p.m. on October 19, 2010 (EDT)
bheiser1 said:
I'm curious about the "no Goretex in winter backpacking boots" stance ... here and in other threads. I notice all of REI's mountaineering boots use Goretex, and a majority of the "backpacking/hiking" boots do.
What about "mountaineering" makes the use of Goretex acceptable where it's apparently dis-recommended for "winter backpacking"? Maybe this is a simplistic view, but it seems the two activities have a significant overlap.
Somehow, "stance" conveys the idea that this is a political thing, founded in personal beliefs ("liberals use Gtex, conservatives stick with old-school leather"). Choice of gear should be based on what works in a given situation (yeah, consideration of local gear shops, where something is made, environmental impact, and other important factors in gear selection is somewhat political).
The practical matter is this:
In theory, Goretex makes the boot, jacket, or other gear waterproof while remaining breathable. In fact, gtx and other waterproof/breathable membranes used in laminates are somewhat limited in their breathability (I will touch on the physics in a moment). In boots, the wpb laminate is a liner in the boot (not laminated to the leather or synthetic main boot material, in other words).
In practice, a number of things will reduce or eliminate the breathability of the liner (or of a wpb jacket or overpants, for that matter). Dirt, mud, body oils, an ice coating, or other contaminants will ultimately block the breathability completely. With a jacket, you can put it in the washing machine with an appropriate cleaning agent, plus you can renew the DWR (durable water-resistant coating) to return the jacket to near-new performance. You can not toss the boots in a washing machine, though you can hand clean them to some extent.
When the breathability is compromised (as it is after a few days on the trail from your sweaty feet and dirty socks), that's it - you now have much reduced breathability, and your sweat may be enough to leave you with wet socks (obviously, this depends on temperature, the insulating quality of your socks, and how much your feet sweat). Some people find that even new, a gtx liner doesn't breath enough and they get wet socks from their sweating feet.
Another factor is that the outer layers of the boot may not be particularly water-resistant - there are a number of gtx-lined boots that have a synthetic mesh outer (Barb had a pair that even let dust through on the summer dusty trails around here). Untreated leather will get soaked, so you may have the outer layers of the boot soaked all the way through.
Well, you say, let's just treat the outer leather layers. If you use a wax leather treatment (say, the traditional SnoSeal) and put too thick a layer, the outer part of the boot no longer breathes, so that even if the gtx liner is still breathing just fine, the sweat can't evaporate through the leather, and you again end up with sweaty socks (and probably blisters). There are leather treatments that do preserve a bit of breathability while blocking liquid water.
Some physics - Goretex, eVent, and other wpb membranes depend on having a pore size small enough to block liquid water, but large enough to allow water vapor (individual molecules) to pass through. If there is a gradient of temperature and humidity between inside and outside (cooler and drier outside), these membranes and the laminates work pretty well. But if the outside surface is wet ("wetted out") so that there is a film of water on the outside, the tiny pores are blocked (that's why it is important to clean your jacket and renew the DWR coating when the rain no longer beads up on the jacket). Waxing the boots also blocks the pores, as does standing in snow with the boot surface covered up or with mud covering the boots. Using the right treatment on the leather (check the manufacturer's recommendations) and regularly cleaning the boots helps. However, a top-quality full-leather boot treated with the appropriate water-proofing treatment will still allow the boot to breathe and repel liquid water, even without a gtx liner.
Well, then, what about Sorels which have a rubber lower part of the boot? Or plastic double boots, which have an impermeable plastic shell that obviously does not pass water vapor? It is true that you can get very wet feet inside either. But the Sorels and plastics have a liner that wicks the water to the top of the boot (it helps to wear a wicking liner sock and wool insulating sock as well - which can help somewhat with a full leather boot or a gtx-lined boot).
Note - two problems with wet socks - first and fastest is that wet socks tend to slide around and promote blisters. Second, if your feet stay wet for extended periods, especially in cold conditions, you may get "trench foot", aka "immersion foot".
The other question - why are "all" of REI's mountaineering boots, and a large fraction of hiking boots made with gtx liners? Main answer is "it's the latest style." People are demanding it when they go shopping. As for the mountaineering boots, a lot of mountaineering is in fairly dry conditions, with relatively brief exposure to rain or stream crossings. When on snow, the boots for the most part are not deep in the snow, so the boot surface is still fairly free to breathe. But if you look at the top-end boots, you will find that the leather ones are full leather and do not have the gtx or eVent liners. Oh, and one other thing about the majority of the "mountaineering" boots - notice that the majority of the ones with the gtx liners do not have a sole made to take step-in crampons (no notch, especially no heel notch). This is an indication that they aren't intended for really serious mountaineering, but are for hiking.