Western Mountaineering on water resistant down and Pertex fabric
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eric chan
(bearbreeder) - F
Re: Re: tests on 10/31/2013 00:08:02 MDT Print View

We have had good success in drying a quilt in the snow by layering another quilt over the top. The inner quilt does dry out, but the outer quilt may get some condensation (or frost!) inside the outer shell. Then you have to deal with that. This is a good argument for using a two light layers rather than one heavy layer.

Hum ... I wonder how one would go with a single layer of fabric (to catch the condensation) over a very good DWR shell? Probably only work under a very limited temperature range. Pity.


a synth overbag is a proven system of course

the other thing that can be done is to put a synth puffy over a down bag instead of wearing it inside the bag ... this allows for a bit better moisture management

theres been stories on BPL of people having the condensation collect on the top of a bivy and it migrating back in the bag through contact ... however an easy test might be to put a windshirt or rain jacket over a bag to see if it prevents condensation as theres more ventilation than a bivy, this definitely prevents the bag from getting wet by external sources (rubbing against the walls)

the problem is that a single nylon layer doesnt really absorb the moisture ... im thinking something like a very light fleece layer which can be squeezed out in the morning ... it should be quite light and can serve as a towel as well ...

i need to do some testing once my leg is healed

;)

Woubeir (from Europe)
(Woubeir) - F - MLife
Re: Re: tests on 10/31/2013 02:57:02 MDT Print View

>>Seems to me you might have made a bit of a mistake in choosing your gear in this case.

What is supposed to be the wright gear because e.g. most people have only one sleeping bag ?

And for those who think now that you can keep a down sleeping bag only dry in weather with only max. a night and a day of rain, I live in a region with a maritime climate and abundanr precipation and more then enough high humidity.

Edited by Woubeir on 10/31/2013 03:05:20 MDT.

David Olsen
(oware)

Locale: Steptoe Butte
What else could you bring? on 11/01/2013 10:40:53 MDT Print View

What is the difference in weight between a down bag and a synthetic bag for the same temp range?

Say for an example 1 pound. Would there be something that weighed one pound that would be more valuable and mitigate the chance of down being sodden?

1 pound would be a pint of white gas. That is quite a few hot cocoas and "hawt nalgenes" to warm and dry out clothing or sleep gear.

1 pound could be a pair of synthetic insulated pants or jacket that could be used over a wider range of activities than a sleeping bag and augment the down bag.

1 pound of peanut butter has about 2700 calories. Enough for a day in most conditions. How many calories in a pound of BigSkyRy's pringles?

1 pound is the weight of a SAT phone.

1 pound is the weight of a eVent bivy.

eric chan
(bearbreeder) - F
Re: What else could you bring? on 11/01/2013 11:09:21 MDT Print View

drying out your bag with hawt nalgenes is what you do AFTER you screw up ... and theres no guarantee you can if your down is saturated enough ... at least without an overbag/quilt for the moisture to migrate too

a thin synth layer on top PREVENTS condensation ...

to put it simply if youre sleep system is at its temperature limit ... and you get condensation or the down bag wet ... you have no margin for error ... you are going to be very uncomfortable at best

and 1 lb is the weight you can loose by not eating cheezy poofs for a week ... or taking a big one in the morning

;)

Hikin' Jim
(hikin_jim) - MLife

Locale: Los Angeles, CA, USA
Re: Western Mountaineering on water resistant down and Pertex fabric on 11/01/2013 12:49:51 MDT Print View

> My experience with down bags, clothing, etc over 40 years says down gets wet quite easily (though DWR coated shells do help some)... and once it's wet it takes quite some time to dry it out... Even exposed to only very high humidity and no direct contact with liquid water, it can lose half it's loft.
My experience is similar. I've had water flow through my shelter on a rainy night (which woke me up). Result: Very wet down. It wasn't hard at all.

Also, in humid/damp conditions, I've seen down bags get quite "limp" and lose a significant amount of loft.

That said, I appreciate the information shared here and am very interested in the "new down". I haven't jumped on board either with the new down -- it'd be pretty expensive to replace all my gear. Also, I have a WM bag (Summerlite), and it's hands down the #1 best bag I've ever used.

HJ
Adventures In Stoving

Eric Blumensaadt
(Danepacker) - MLife

Locale: Mojave Desert
The week-long-damp-bag winter problem on 11/01/2013 14:22:07 MDT Print View

Sure, good goose down from mature geese is great. Eider down even better.

But remember, sleeping in a down bag on a week-long winter trip results in a bag that collects moisture every night. There is usually not enough time to thoroughly dry the bag each day and it ACCUMULATES moisture. (See Scott polar expedition.)

This not only makes the bag heavier each day but reduces the loft and insulating ability of the down fill. THIS kind of scenario is where DWR treated down comes into its own, IMHO.


Now the problem for Western Mountaineering is WHICH down DWR is the best?

Testing one down DWR is fine to get an idea of the concept's pros and cons.

Testing all the down DWRs out there is where the best answer lies.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
DWR is not going to work for us on 11/01/2013 15:42:45 MDT Print View

For DWR to be of any use in a quilt or a jacket, it must stop the down from collapsing. There are two different cconditions it has to handle: water, and ice.

First of, note that water or ice can still collect all around the micro-fibres of a down tuft, even if the surface of the down tuft is 100% waterproof. There is nothing to stop it. A DWR-treated shell (or even a GoreTex shell) cannot stop the water vapour from getting inside the shell either. Only a vapour barrier can do that.

Ice itself around the down tufts inside a shell will cause some problems, and no amount of DWR on the down will do anything about ice forming inside your quilt if it is cold enough.

What about dampness (rather than ice)? It will soften the keratin in the down tufts and leave them limp and flat, with a loss of loft. To handle this you need to block water vapour from penetrating into the down tufts. But a DWR does not do that: it blocks liquid water from 'wetting' out the surface. So water vapour will go straight through the DWR layer into the down fibres and you will end up with a limp zero-loft mess.

This is why companies like WM are not convinced about these DWR treatments. They do not work in Real Life. They only work in gimmicked demos with the down stuffed in a bottle of water. Its 99.9% marketing spin again.

Cheers

Edited by rcaffin on 11/01/2013 15:43:34 MDT.

Hikin' Jim
(hikin_jim) - MLife

Locale: Los Angeles, CA, USA
Re: DWR is not going to work for us on 11/01/2013 15:48:35 MDT Print View

Wow. Very incisive comments, Roger.

HJ
Adventures In Stoving

Larry De La Briandais
(Hitech) - F

Locale: SF Bay Area
Re: DWR is not going to work for us on 11/01/2013 16:27:33 MDT Print View

"It will soften the keratin in the down tufts"

Couldn't the DWR treated down tufts prevent/slow this process? I'm truly asking as I have no idea myself, but would love to learn how this really works.

David Olsen
(oware)

Locale: Steptoe Butte
Re: Re: What else could you bring? on 11/01/2013 16:43:59 MDT Print View

"drying out your bag with hawt nalgenes is what you do AFTER you screw up ... and theres no guarantee you can if your down is saturated enough ... at least without an overbag/quilt for the moisture to migrate too"

Use a hot water bottle to dry your bag before it gets sodden from days of use in humid conditions when their isn't sunshine to do the same.

Heck, I am a belt, suspenders and another belt kind of camper. I like a vbl, a down bag and a synthetic overbag if I am winter camping for a couple of weeks or more. Sometimes 2 vbls (one a jacket under my down coat). Some of my colleague's used a bivysack over all that. I also use hot nalgenes to help dry all the clothes and boot liners I stick in my sleeping bag.

I have camped for 28 days at a stretch with a -20 synthetic bag at 0 degree temps and found myself getting colder each night as
the bag lost it's loft from moisture and compression. We finally ended up adding a synthetic overbag on the next trips.

Found a +20 degree quality down bag was warmer in the long run than a cheap -20 degree synthetic for multiday winter trips. (When used with an overbag).

Haven't tried the newest primaloft or climashield in those conditions tho.

Edited by oware on 11/01/2013 17:12:30 MDT.

Woubeir (from Europe)
(Woubeir) - F - MLife
Re: Re: DWR is not going to work for us on 11/01/2013 16:47:21 MDT Print View

AFAIK no. From what I remember from one of my biochemistry courses, I think it has something to do with alpha/beta-keratin changing in alpha/beta-keratin due to moisture vapor and a DWR does nothing to prevent that.

Edited by Woubeir on 11/01/2013 16:58:15 MDT.

ROBERT TANGEN
(RobertM2S) - M

Locale: Lake Tahoe
Vapour vs. vapor on 11/01/2013 16:48:10 MDT Print View

Roger, is a "vapour barrier" similar to the American "vapor barrier"?

Larry De La Briandais
(Hitech) - F

Locale: SF Bay Area
Vapour vrs vapor on 11/01/2013 16:53:56 MDT Print View

va·pour (vpr)
n. & v. Chiefly British
Vapor.

vapour US, vapor [ˈveɪpə]
n
1. (Physics / General Physics) particles of moisture or other substance suspended in air and visible as clouds, smoke, etc.

Franco Darioli
(Franco) - M

Locale: Melbourne
Western Mountaineering on water resistant down and Pertex fabric on 11/01/2013 16:56:40 MDT Print View

Yes in Australia we speak English.
favour, honour, labour, odour, ... rumour, saviour, splendour, tumour , vapour
However we can handle terms like stake,cookies,pavement and all of that.

David Olsen
(oware)

Locale: Steptoe Butte
Re: Vapour vs. vapor on 11/01/2013 16:58:31 MDT Print View

"Roger, is a "vapour barrier" similar to the American "vapor barrier"?"

Yes, just with more flourish.

eric chan
(bearbreeder) - F
Re: Re: Re: What else could you bring? on 11/01/2013 17:59:13 MDT Print View

I have camped for 28 days at a stretch with a -20 synthetic bag at 0 degree temps and found myself getting colder each night as
the bag lost it's loft from moisture and compression. We finally ended up adding a synthetic overbag on the next trips.


which is why ive said repeatedly over the years that if you have a synth jacket put it OVER your downbag when sleeping ...

and using down under synth is the "ideal" for of moisture management

in winter youre spending the fuel anyways to melt water, might as well do it overnight and warm up your bag ... but in the shoulder seasons you generally arent going to boil water every single night ... and in those temps a synth bag is much thinner than a -20F one

to put it simply a thin down layer will actually dry FASTER than a much thicker and heavier synth one simply due to the moisture content vs drying area ... however a synth layer of roughly the same weight will handle moisture better and provide some insulation when damp ... the trick is to have the INSIDE dry, which is not hard with a hawt nalgene

again to reiterate .... its is exceptionally hard, if not impossible to dry very damp sleep system at the limit of its temp rating without the sun ... once it gets that way you better pray you have excess insulation somewhere, enough fuel for MANY hawt nalgenes, a fire, or can get out of dodge quickly

a damp synth at its limit will still degrade, but slower, and it provides some insulation when damp (not wet) ... and is MUCH easier to dry out even without the sun

ideally you would want a second over layer ... something you "sacrifice" but can dry easily enough during the day when walking, or where it doesnt matter if its a bit damp ... ie an overbag or synth jacket

if im worried about condensation ... i put my jackets over my bag ... in the morning i can wear em till the heat dries em out

;)

Tom Lyons
(towaly) - F

Locale: Smoky Mtns.
VBL on 11/01/2013 18:14:56 MDT Print View

In these conditions, a VBL is appropriate.
A VBL prevents moisture build-up in the insulation from body moisture.
But the heat still warms the insulation and bag, and drives humidity out.
If you use a VBL inside the bag, then you can also use a non-breathable VBL bag on the outside too, with impunity. This keeps moisture from condensing on the outside of the bag.

There is nothing new or revolutionary about this idea.
It works.

peter vacco
(fluff@inreach.com) - M

Locale: no. california
Re: Re: Re: What else could you bring? on 11/01/2013 19:04:39 MDT Print View

" Found a +20 degree quality down bag was warmer in the long run than a cheap -20 degree synthetic for multiday winter trips."

oh yes. syn insulation seems to work "ok" , but then when you get to the end of it's working range .. not good.
the down on the other hand,s eems to keep getting better as things get colder. like having sombody lighting a flare down there and it gets al warm and good.
i have swam (swum? ) a river and got my down bag so drenched that water was running off it inside. whatever.. i still slept ok fully dressed (was a stinking mess anyway).
this leads me to think that down takes some long term soaking to be really nasty wet (done that too).

as far as overall weight (this being bpL), methinks that by the time you opt for a syn overbag, you're better off with a real tent and a down bag, and living with the odd colder night on occasion.
but, as said above by the time your down is quite drenched, you've got a mofo (he didn't actually say that , but ... ) of a problem to dry it sans sun and some heat.
this is where you want a tent.

v.

Eric Blumensaadt
(Danepacker) - MLife

Locale: Mojave Desert
"Vapour" and DWR on 11/02/2013 00:39:48 MDT Print View

Roger,

How do you know that the DWR is merely a surface treatment and has not penetrated the down plumule?

If it has penetrated the plumule than water vapor can't displace it.

This is where the chemical composition of the DWR as well as its method of application can make the difference.

I dunno if the curent down DWRs available can penetrate the down but we need to have a wait-and-see attitude about this.

Mountain Hardware and others need to test the DWR treated down for resistance to vapor over time.

Edited by Danepacker on 11/03/2013 19:31:31 MST.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: "Vapour" and DWR on 11/02/2013 04:49:38 MDT Print View

Hi Eric

> How do you know that the DWR is merely a surface treatment and has not penetrated
> the down plumule?

Once you go from a surface treatment to a volume treatment you are using a huge amount more chemical and the weight rockets sky high. I am assuming that the treatment does not turn 1 kg of down into 2 kg of treated down (as it were).

Also, since I know more than a little about the various forms of keratin (eg wool & feathers), I have some serious reservations about the technical feasibility of a volume treatment. Frankly, I just can't see it.

Cheers