Pack straps and W/B jacket seepage

"I go for a walk every day after work, carrying a HMG Windrider pack with 20# in it. I do a 2-hour loop"

"Could the fabric be so poor that even extended light contact with pack straps render it water-permeable?"

Possible, although I'm surprised to hear about it with light use on a 3 layer garment. It's not uncommon with a 2.5 layer fabric.

250 days x 2 hours = 500 hours = 50 trail days. Plus other excursions.

Go into a dark closet and shine a light through it.

I figured that if there were any mechanical breakdown, it would be visible. Like crinkly shell surface, delamination, puckered lining scrim…. basically anything. The fabric looks perfect. Odd. It does seem to be having issues roughly along the same timeline as my Neoshell jacket. Maybe for me ~1 year is the life of W/B shells even when I am nice to them. It's not like it rains here every day. Most days I don't walk in a rain coat.

– dwr wears off … The U of leeds has shown that DWRs might not last more than 100 miles of constant pack abrasion

– when dwr wears off that part of the jacket cannot breath

– when that happens you might as well be wearing a plastic bag on that area

– refresh the dwr with grangers and low->moderate heat in the dryer

– at a certain point the fabric will no longer hold a dwr no matter what … At that point its time for a new jacket

Its possible as well that there is a failure of the fabric itself, on one bpl test a montane event 3L jacket failed and would leak … Do a search for threads on event on UKclimbing and the users there tend to state event doesnt lat as long as goretex

Which comes back to this …

– refresh your DWR

– dont use your rain jacket for urban everyday wear if you want it to stay in tip top shape, especially if yr carrying a bag

– buy rain jackets from companies with stellar warranties

;)

Another simple test is to place a shoulder area in a large bowl, fill it with water, gather it together into a water-filled sphere, and squeeze.

Do it in the bathtub.

I found a seam leak this way.

3 years ago I sent a 3L eVent jacket with modest mileage to a friend to use on an Aniakchak trip. I refreshed the DWR before mailing it. The failure he reported was pretty similar to yours; fairly copious leakage under the straps, belt and lumbar.

There aren't too many such reports, but I've heard enough similar stories that my faith in eVent is limited.

> Is there some 'mechanical' force at work here pushing the water through the fabric.
Exactly. The fabric will withstand water up to a certain pressure, above which the water will be able to push through. That is the fundamental concept behind the idea of a hydrostatic head (HH) or pressure rating. When the pack straps press on your shoulders they raise that pressure under the straps. A bit like getting a damp knee when you kneel on a groundsheet. Yes, that happens too.

Of course, after a few years use that HH rating will fall. Some of the loss will likely be due to micro-mechanical damage to the eVent membrane. Some of that loss might be restored by a DWR treatment, but rarely all of the loss.

This is one reason why many use a poncho instead: it goes over the pack straps rather than under them.

Cheers