on 1/26/2001 8:06 PM, mike miller at mwmiller@CWNET.COM wrote:

> I thought Gore-Tex passed water vapor and stopped water in drop form.  Not?
> 
> 
> ----- Original Message -----
> From: Karl Ploessl <ploessl@SUNMAC.SPECT.UPENN.EDU>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Friday, January 26, 2001 2:13 PM
> Subject: Re: Westy height ?
> 
> 
>>> Philip wrote
>>> 
>>> [...] There is ,however, a goretex cover between it and the snow :-)
>> 
>> why would you use a goretex cover? goretex only works if you have a
>> temperature gradient warm - cold and I can't see that your Westy sitting
>> outside is warmer than surrounding air. Just my thoughts and it is Friday.
>> 
>> Karl
>> '81 Westy "Jenny"
>> Wilmington, DE
>> 

Yes and no. The fabric does not 'breathe' on its own.
That's why you don't see backpacks made of Gore-Tex� fabric.

Gore-Tex� fabric requires the "human engine" to propel the vapor through the
fabric. No difference of pressure between outside and inside = no vapor
transmission. That's why you still feel clammy if conditions are warm. It's
just not possible for the human body to generate the difference of pressure
required under those circumstances. Gore-Tex� works best in cold/wet
cold/dry conditions.

The "pore" structure of the fabric is such that water vapor is smaller than
the holes and water droplets are huge in comparison.

Dave Caston

GearKnowledgeWorks!, Founder & President
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