waterproofing leather boots

[Phil Cook]

Individual water molecules are the same as water vapour ones but they are bonded together by relatively weak intermolecular bonds. The bonds between the H and O atoms are not symmetric and so the H and O of different molecules are attracted to each other. You can't get liquid water molecules through the breathable membrane without putting energy into it to separate the intermolecular bonds thus creating water vapour.

In real life you will not get water vapour to flow from a cool environment outside your jacket to a warm one inside it.

The coating on the outer face of breathable fabrics is there to attempt to prevent the face wetting out and creating a barrier to water vapour molecules.

The reasons breathable fabrics fail to keep you dry are that they either leak (at openings or places where the membrane has failed) or that they are incapable of transmitting the amount of water vapour you are sweating into them to the outside.

[stuart noble]

Interesting. ISTR waxes cannot form a continuous film but remain a series of individual molecules. I wonder whether the gaps between the molecules allow the passage of vapour and, if so, whether consequent applications would close those gaps.

[nmm1]

Well, maybe. I accept that is true under simple conditions, but real life isn't that simple. Inter alia, one of the reasons that Goretex says that its fabrics must be kept clean is that 'dirt' can act as a flux. Also, rubbing causes transient overpressure which can cause 'breakthrough' - and, once that has happened and both sides of the pores are wet, the surface tension effect is (mostly) lost.

There is also the question of what the overpressure is for pouring rain being driven by a force 7 gale :-)

I am not convinced, though I have been unable to measure any flow. What I have seen is water on one side, in conjunction with rubbing and probably dirt cause darkening and a feeling of damp on the other. This matches with what I know of the physics involved.

That is true. As we both know, perfect waterproofing is a complete waste of time for UK conditions, for that reason alone.

Not at all. Those tests almost certainly require a maximum level of leakage, which can be regarded as negligible. That's reasonable, but NOT the same as claims of perfect waterproofness.

Regards, Nick Maclaren.

[Peter Clinch]

"both sides" implies a sheet. I'm not sure but I was under the impression you have more of a slab, albeit a thin one, so you'd have more than one layer of pores as a barrier. Though as noted, I'm not sure how thick (in terms of how many pores have to be negotiated on average rather than measured distance) the barrier really is.

That would be a clear problem with tent flys, that typically have HH levels far lower than Goretex. I said over 4m for XCR but my mistake, it's actually over 40m! Tent flys are usually 2-5 m HH.

The other elephant in the sitting room is the damn great holes for heads, arms etc. required to use the garment in normal situations. And once the water gets in all those miracle wicking under-layers do their stuff!

[RJH]

I would add, and how to put this delicately, it does depend upon how sweaty you are.

Goretex boots work well for me, but the clothing is rubbish because I sweat 'a bit' given the slightest movement. By pure luck I've come by a Rohan 'barricade' coat that works for me.

Rob

[Gordonbp]

I second that - having had several Goretex jackets and getting damp underneath from sweat, I found eVent and my Rab Latok now breathes well!

[PeterC]

Hadn't heard of these two but I haven't liked Goretex since it first came out - something to do, IIRC, with it being described as "breathable". As it happened I had a long break from walking and when I started again almost all of my kit was inadequate - 30 yo leather boots /and/ my feet had changed quite a bit. With some doubts I looked for modern kit and was pointed towards Paramo. I does seem to work well, unlike the modern Scarpa boots which aren't as good as my first leather pair from 40 years ago - nut the Scarpa do have Goretex in!

[Bill Grey]

Having walked my dog pretty well every day for the best part of 10 years, in all weathers, in long wet grass, mud snow and rain, often had the bottoms a of my trouser legs soaked but my feet never were wet, My hillwalking days I enjoyed, and always had Gortex lined boots - no problem.

Bill

[nmm1]

I used to use Goretex for serious walking, but also found it sweaty. It is vaguely breathable, but only in very dry (and warmish) conditions. But I moved to Paramo because Goretex was too cold on its own climbing uphill, and a jersey underneath was far too hot! Paramo may not be as waterproof, but is more breathable and generally comfortable.

I haven't yet exposed to Paramo to really wet conditions (which means

3+ days of heavy, driving rain, sleeping out), but it seems to be OK in moderately wet ones.

For boots, at least Goretex doesn't leak like a sieve after the first

3 days of sodden conditions (as over-flexed leather does), and I am not expecting miracles (i.e. feet that stay actually DRY under those conditions). While I suspect that it is stitching that causes the leaks (it is definitely NOT trickle-down), I can't rule out the pumping effect. But the amount is livable with.

Regards, Nick Maclaren.

[nmm1]

I have never had any trouble under such mild use, either, nor did I with other fabrics and materials. Most of them work tolerably well day-by-day, if you can get them at least dryish overnight; it is the third and subsequent days out in conditions that make most dogs want to stay indoors that distinguish the waterproofness of materials.

Regards, Nick Maclaren.

[Bill Grey]

You seem determined to play down my experience with my Gortex boots/trail shoes, you comment of "mild use" is quite patronising seeing as you don't really know the conditions in which they were used.

Very wet is very wet.

Your remark "... it is the third and subsequent days out in conditions that make most dogs want to stay indoors that distinguish the waterproofness of materials." .....sums up their use quite accurately.

You go your way, Ill stick with my truth.

Bill

[Andy Champ]

I'm cross-posting this to uk.rec.motorcycles, because they are rather familiar with the problems of high wind speeds and rain.

See embedded.... Andy

[Grimly Curmudgeon]

If you manage to find any that still ride in the rain.

[sweller]

Snow and rain - of course.

I don't seem to do a great deal of riding in the summer...

[sweller]

I regularly wear standard leather boots in all weathers on a motorbike

- they're old German para boots, very common 20+ years ago. Mine are still going strong.

The best stuff for waterproofing has been Nikwax regularly applied, although I have used dubbin which is good but not as good.

I'd use Mars oil because I like the smell but it's not that effective.

The problem with them is on two counts: [1] once they're wet they stay wet and take ages to dry; [2] if they're wet and it's very cold unless they're in your tent and haven't been discarded in a pissed up heap they freeze and can't be put back on readily.

[Thomas Prufer]

I had, somewhere, the catalog of an outdoor supplier. They said that for tent floors, such-and-such head (10 meters? 20? I forget, but it was it was a lot more than I would have expected) was a reasonable lower limit to keep the floor dry-ish in rain.

Moving around on the tent floor would "work" the water through; dirt from below would make it worse. This agrees with the above... (They also said to put a cheap tarp or plastic sheet under it to help keep away water, dirt, and holes.)

Thomas Prufer

[PeterC]

A groundsheet that's adversly affected by dirt...! Now there's good design! Never had any trouble with the ripstop and PVC(?) floors in the old (70s) tents, including one morning when there was a streamlet under the tent.

[ogden]

Don't judge others by your own low standards.

[ogden]

I've worn Goretex kit in rain at up to 160mph and stayed dry.

In "high wind speeds", I tend to worry more about what's in front of me than the science behind why I'm not soaking wet.

['Mike']

Nice and dry when my son drove his Bluebird up to that speed and clear so he could see where he was going ;-)

My Bonneville doesn't go out in the rain, which means it hasn't been out very much :-(

Mike