If Gore Tex drysuits, etc are waterproof without having other waterproofing agents added to the fabric, why are those agents used? Thanks.
I think I had heard years ago that Gortex had the pattern.
Evidently the materials that use waterproofing agents don’t want to pay for the Gortex material.
A interesting note on Gortex: When we were up in AK, the locals in Juneau wouldn’t use it at all. They said that it broke down in salt water after a certain period.
They said the best thing that they could say for it was that it was “cute”
My wife and I had our Performance gortex biking rain pants and tops, and after a week or so in pouring down rain and them sweating like hell in their Helly Hansen rubberized rain gear and us staying dry an comfortable,
a couple of them were going to order some.
Two possible reasons
for the Durable Water Resistant (DWR) treatment.
1. To decrease evaporative cooling. The more water the nylon outer layer is holding the more cooling you get when you stop paddling or stop getting the fabric wetted by rain or waves especially if it is windy. The DWR causes the water to bead up and roll off the fabric instead of soak into the fibers.
2. To increase breathability - The water vapor inside the Gortex layer needs to pass through it as vapor. If the outer nylon shell is saturated enough so that the outer surface of the Gortex is in contact with liquid water then the vapor will not pass through as well.
The Gortex layer will keep water out even if the outer nylon is completely saturated, but you just will not be as comfortable.
I am not a fabric engineer, but the above is what I have heard in several different discussions.
You’re right, Mark. And getting splash
water to roll off quickly, rather than soak into the Nylon surface, is very helpful for reducing evaporative cooling.
Prevents outer from being saturated
If the outside is soaked, even though no water will pass into the drysuit, you will feel the coldness, especially if you are wearing only a thin underlayer. (Conductive cooling?)
This is also true of neoprene wetsuits. If the outer is still beading up water so that it rolls off, you just feel warmer.
(PNet is great, ain’t it?)