Which fabric for DuoMid for my expected conditions?

[Jason Brinkman]

I could not be happier with the silnylon DuoMid that I acquired early this fall for shoulder season use (I bivy all summer). Ventilation is great. Condensation is less than expected. However, I live in a pretty dry climate, and a few inches of snow is nothing like constant rain, so I can't really suggest what to use on the coast.

[Julian Thomas]

in that photo the pack looks very like colin ibbotsons 'skins' pack

EDIT:
Ok, having read the text, it IS the skins pack

[Jack H.]

Agreed. Misting is often full blown raining inside shelters. I'm pretty fed up with silnylon shelters and am looking forward to more manufacturers sourcing *waterproof* silnylon. MLD's Shield fabric is at this point (poorly written) marketing hype. I'd like to see some in person and see some tests from the long distance trails. Golite and Granite Gear have been sourcing more waterproof fabric for a few years now. And I've been disappointed repeatedly with the waterproofness from Henry Shires and SMD.

The Duomid looks great, and if the silnylon version is *actually waterproof* after a few months on the trail, I might be a buyer.

[Don Selesky]

I've spent a rather unpleasant three hours in a hammock under a Cuben tarp, getting my face splashed on because of water penetration through the tarp. Granted. it was a classic horrendous Vermont rainstorm that I wouldn't have wanted to drive through, but it made it impossible to fall asleep until it was over. I got a good idea just how bad the "misting" can be, and was thankful that the rain finally stopped.

[Miguel Arboleda]

Cuben mists? I was under the impression that cuben is completely waterproof.

[David Olsen]

The angle of the fabric walls has a lot to do with snow loading and condensation build up. The steeper the better.

[BlackHatGuy]

"And I've been disappointed repeatedly with the waterproofness from Henry Shires and SMD."

FWIW, I spent an evening in a Contrail in a deluge (which, I think, is slightly worse than a downpour). Rained heavy for a good part of the evening. Very slight misting, and I mean very slight, nothing like raining in the shelter, was all I encountered. I was pretty impressed with how well the Contrail handled it, especially since Henry is quite transparent about the waterproofness (or lack thereof) of his shelters. I expected worse.

[Matthew Swierkowski]

I agree that misting is problem, and it seems to vary depending on the quality of the sil-nylon (to which I have no way of determining the quality of different sil nylons myself other than experience with different things made out of sil). I have 2 tarptents (Squall and Double Rainbow), and a Equinox poncho/tarp all made out of sil. I have not yet been misted on in the DR, I been very lightly misted on in the Squall (in an extreme deluge), and the poncho/tarp leaks like a sieve (I almost wonder if that thing even has any silicon left on it).

The good thing about sil is it is very durable, lightweight and can be "fixed" or should I say retreated. I have done what I call the "Jim Woods" treatment (see his website for details) to my Squall, and it made it more or less waterproof. The treatment is simply diluting silicone sealant using mineral spirits and painting it on. It adds minimal weight, and you can get as "stupid" with it as you want. I.e. if you want a real thick coating (will be heavier) then don't dilute it much, and if you want a thin film then dilute it a good bit. I did a coating of the underside of the entire canopy and inside floor of the Squall using about a 4:1 ratio (mineral spirits to silicone sealant) and it added less then 2 oz of total weight to the shelter. Only tradeoff is the thicker the coating applied the more tacky it gets.

I'm currently experimenting with the Aksto spray on silicone on my poncho to see how that stuff works. It's a lot easier to apply.

By the way, didn't mean to get off topic here. Just wanted to note that there aren't many fabrics as light and durable as sil, and the tradeoff seems to be that it may need re-treatment at some point in time.

I actually just ordered a DuoMid in sil a week ago myself assuming that I would have to treat it at some point in time. Maybe this new shield sil will resolve that…that would be awesome.

[Roger Caffin]

I think Don's experience is a good example of what 'misting' really is. Cuban is waterproof, period. So what Don was experiencing was condensation being knocked off the underside of the fly.

Yes, I know people rave on about how their tent/tarp/fly either leaks or doesn't leak in a storm, and claim it couldn't possibly be condensation. Well, I have to say that in most cases their claims have to be simply ignored. Under the right conditions you get condensation on the inside of a fly and rain knocks it off in a mist.

Now, that does NOT mean silnylon can't leak under pressure. Unfortunately current American-made 'dry-look' silnylon is not made to be waterproof for our needs. It is made to hold air in bulk, for sports parachutes and for those idiot blow-up advertising figures you see by the side of the road or on roof-tops. That's all. The stuff leaks at about 10 – 15 kPa (about 1 – 1.5 m water head). Yes, I have done a lot of proper pressure testing.

Of course, if your leak is coming from a seam, well, it's leaking. Sure.

The old 'wet-look' silnylon was waterproof, up to about 70 kPa or 7 m water head. But you can't get it any more.

There are some Asian versions which have a similar pressure rating of 10 – 15 kPa, and there are some other Asian versions which are GOOD (70+ kPa). But the latter are very hard to source. Sorry – I do not have a source at this stage. I WISH!

Cheers

[Jack H.]

All that testing is fine and dandy, but doesn't jive with the dozens of thruhikers that I know who swear that silnylon leaks. You can get wet from condensation being hit off by rain drops, and you can get wet from leaking through the fabric.

I've used silnylon shelters for about 600 nights at this point…

[Andrew Richardson]

Hmm…anecdotal evidence or scientific tests, which is more believable?

If a fabric is waterproof to a certain pressure, than it is waterproof up to that pressure when it is in similar condition to the fabric tested. Perhaps something happens during a thru-hike to change the properties of the fabric? Sun exposure? something like this…who knows.

Silnylon from the same company can vary in quality, but a good roll will perform as the tests predict. Why would this not be the case? Regardless of what anyone said happened?

[Ron Bell / MLD]

Hi,

Ummm- maybe the whole misting question could move to a new thread all it's own…. Seems the original thread question of "Which fabric for DuoMid for my expected conditions?" has been answered.

Thanks,
Ron

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