If eVent is So Great . . . .

[Tipi Walter]

Here's my question—if eVent is so great as a shell fabric, why has a company like Feathered Friends dumped their eVent choice and instead use Pertex?? Is there something about Pertex which is even better than eVent??

[David Ure]

Probably weight. Event is great but it is a heavy fabric and really doesn't compress well for use in sleeping bags. That's my contention but I am sure there will be other answers.

[Dan @ Durston Gear]

Is the Pertex they're using the newer WP/B stuff? Or just non-waterproof normal Pertex?

In general, myself (and a lot of people) don't like WP/B sleeping bags, so if they moved away from this then that's understandable. If they moved to a different WP/B, it's probably weight as David said.

[Tipi Walter]

They use Pertex Shield EX and XT. Luckily the parka I have of theirs has eVent which I seem to like a lot. Supposed to be better than goretex, etc. Has Pertex the good reputation of eVent??

[kevperro .]

I just bought a pair of Event lined boots. Never used them and didn't buy them because of the liner but because they feel good on my feet.

I'm in the camp of not wanting a waterproof breathable layer on a sleeping bag. I DWR is fine to keep off drips and shed condensation from the fly. If I slept in snow caves I'd carry a bivy, and for casual condensation and such I'd rather manage that and keep the sleeping bag as breathable as possible. Most of the moisture it is exposed to is from your body. Anytime you put a less breathable layer in it's path to shedding that moisture you increase the retained moisture in the down. It will dry slower too.

[Stephen M]

I have a lot of Event items and the breathability is top notch.

2 waterproof shell tops and bottoms.
Down jacket and trousers.
Bivy.
Winter gloves
Pack liner.
Sleeping bag compression sack.

[Roger Caffin]

I don't KNOW, but I am willing to make some guesses.

Fact:
eVent may be 'breathable', but ordinary Pertex or similar uncoated fabrics are at least 10x more breathable, or maybe 100x when you count actual air flow.
Fact:
A major hazard for down bags and quilts is getting condensation inside the shell under very cold (ie winter) conditions.
Fact:
A major method of getting rid of condensation from inside a shell is actual air flow: it carries the water vapour out with it. This is hugely faster than water molecule diffusion.

Many of us do not like having any coated fabric on the outside of down gear, for all the above reasons. In other words, yes, any air-breathable fabric is better than any coated fabric for the outer surface of down gear.

Cheers

[Tipi Walter]

Thanks for the replies. Pertex Shield is a polyurethane waterproof breathable fabric, same as eVent (or at least breathable like eVent). Wouldn't the Pertex also impede full venting like eVent? Dangit, I have to be a fabric engineer to understand this stuff.

[Chris Townsend]

In my experience Pertex Shield isn't as breathable as eVent. It's considerably less expensive though.

I've used sleeping bags with various W/B shells over the years and mostly they work okay. Only on long trips in really cold weather have I had dampness build up inside. Airing them regularly inside out gets rid of most accumulated moisture even in very cold weather.

That said I prefer bags with non-waterproof breathable shells as these are generally lighter weight and more compact for the same warmth.

[Tipi Walter]

I agree. My fave is the microfiber on the WM bags.

[Roger Caffin]

Hi Walter

I was not specific enough. By 'Pertex' I meant the UNCOATED fabrics, which do breathe. Pertex shield is just another coated fabric with zero air porosity.

Cheers

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