Poncho Vs. Rain Jacket

Cost versus durability primarily determines the criteria for choosing Propore based raingear versus Entrant or eVENT.

Material…..Cost…..Durability
Propore……x……..x
Entrant……5x…….5x
eVENT……..10x……10x

The actual raw material cost for Entrant is only about 15% of eVENT or Goretex. Montbell and Patagonia generally have steep mark-ups.

Hi Richard

> A light silnylon poncho will block about 8.7 PSI and the ultralight silnylon ponchos will block about 2 PSI.

The last time I measured the pressure rating of silnylon I got figures between 10 and 12 psi.
I'm curious: what (source) silnylon were you measuring?

Richard, your analysis was excellent. I settled on an epic-like windshirt(Houdini), and a jacket(North Face DIAD in HyVent). I believe the TNF HyVent is comparable to eVENT in construction, an oil-resistant inner layer and a microporus outer layer, is that correct? It really breathes well; no comparison to goretex.

Roger-Your question made me laugh because you were my source for 8.7 PSI. I couldn’t find any end user silnylon product for sale to the US ultralight backpacking segment which had a spec higher than 4.3 PSI. I knew that you were a fabric expert and you have a hydrostatic tester in your lab. I included your higher 8.7 PSI number because of your impeccable credentials.

Your Bush Walking site stated that silnylon was available up to 60 kPa (8.7 PSI). See Bush Walking Article

I also found a review where you referenced one of your silnylon tests resulting in 8.7 PSI.
See Back Pack Gear Test This long address would not hot link. The address is http://www.backpackgeartest.org/reviews/Rain%20Gear/Jackets%20and%20Pants/Frogg%20Toggs%20Pro%20Sport%20Suit/Roger%20Caffin/Field%20Report/

Integral Designs silnylon tarps is a representative product sold to ultralight backpackers in the US and their fabric is rated at 1 PSI.
See Integral Designs

Jim Woods did a lab test on a broad range of US silnylon products and found the hydrostatic range to be 1 – 2 PSI. See Jim Woods

Gossamer gear specs the silnylon used in their products at 2 PSI. See Gossamer Gear FAQ

Backpacking Light reviewed two silnylon products in which the silnylon PSI rating were specified. The lower rating was 2.8 PSI and the higher rating was 4.3. See Cordura Silnylon and Tarus Ultralight Tent

You said that you tested silnylon products in the 10-12 PSI range. I accept that there is silnylon available with those specs but…

First, this is still well below the threshold of being a waterproof product (25 PSI).

Second, I cannot find any silnylon product targeted toward ultralight backpackers in the US that uses this higher PSI silnylon material. Can you fill us in on the source and other specs for this material?

Richard,
what is your source that states that both Patagonia as Mont Bell use Toray Entrant GII. I've found that the 2,5-layer Patagonia use Entrant DT, but I haven't found anything about their 3-layer material. Based on some sources, my guess is that it is actually a laminat rather than a coating with suggests it would be dermizax rather than entrant.
For Mont Bell, I haven't found a source that confirms that the Mont Bell material is made by Toray. Breeze Dry Tec as used in the Peak jacket is claimed by Mont Bell to be a microporous laminate (microporous dermizax ?) so couldn't be Entrant GII as that is a coating.

About the PSI rating, I have looked to the numbers from Hilleberg and their Kerlon fabrics are rated with a hydrostatic head of between 3 and 4,5 PSI. OTOH, I haven't hear anyone complain about a lack of waterproofness of the fabric. If normal rain exerts a pressure of 7,5 PSI these fabrics should start to leak rather fast, but that does not seem to be the case in practice. So other factors have to be involved which influence this.

Brett,
TNF Hyvent is also based on Toray Entrant/Dermizax.

Roger,

Would the amount of tension applied to the fabric change the PSI?

My experience suggests that the silnylon tarp pitched very taut will have more misting than the same tarp draped over a pack.

Richard and Tom -Think of rain in terms of droplets crashing into the fabric. Each one has a mass and velocity depending on how "heavy" the rain is. This gives it a penetrating ability and is proportional to its kinetic energy… a bit like a bullet from a gun: heavier, faster bullets have more energy. (Kinetic energy = 1/2 mass times velocity squared.). The ability for a silnylon fabric to absorb the energy of the rain is dependant on a number of factors:

• Fabric weight
• Fabric porosity
• The angle of collision
• How much the fabric can move

It is as Richard said, “My experience suggests that a silnylon tarp pitched very taught will have more misting than the same tarp draped over a pack.” And as Tom said, "So other factors have to be involved which influence this." (waterproofness)

The porosity, in a large measure, determines the PSI rating. The angle of collision can be just about anything, with perpendicular being the worse case scenario. The energy absorbed from the collision depends on how the fabric moves and how the rain drop distorts. It is the force the fabric exerts on the water acting over a certain distance (energy = force times distance) or the work done by the fabric. This is similar to a Kevlar bullet proof vest which distorts to slow down the bullet.

Tom- You asked what is your source that states both Patagonia and Mont Bell user Toray Entrant GII?

Colin Thomas and Mark Verber
BPL has a bug in their forum software that throws away links if they are above a link size they think is reasonable. The link they discarded is http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/52/index.html?skip_to_post=489#489

I don’t place much stock in the manufacturer’s marketing descriptions of their unique WPB products. I just try and match up their claimed proprietary technology with known patented technology to guess at the actual source.
Toray’s Specs

Richard,

I can not reconcile those numbers with my experience. I use a Campmor UltraLite Extension Poncho/Tarp (9.3 oz.). I have been caught in nasty blowing thunderstorms above timeberline and stayed dry. I also use it for the fly on my Hennessy hammock. When it is taut and perpendicular to the rain it will mist a very small amount. For a short time the bug net is enough barrier, but occasionaly I supplement it with a Gossamer Gear spinsheet (3.3 oz.).

My experience tells me it keeps me dry enough. Those numbers tell me I am all wet. What am I overlooking?

Richard – This answer is speculative… "dry enough" is attributable to 1) the give of your garments under the poncho and 2) your body heat is vaporizing the water that passes through.

This question defies consensus similar to the questions of: religion and politics, do Epic tents keep out rain, and is Pertex and Pile better than Gore-Tex for use in rain?

YMMV

Dont know if the trips are for you or wife your wife. If it is my friends and I then it is my Gatewood Cape and my Montane Featerlite pants which doubles as both wind pants and extra rain protection and my Montane Featherlite Smock. Same for that. I have a shelter, pack cover, and rain protection for as little as 18oz.

Tom, thanks for the info that my DIAD is just Toray Dermizax. Very disappointing that it is 'only' as breathable as goretex. Back to saving pennies for my ID eVENT Thru-hiker..
Anyway, while researching Dermizax, the pdf pamphlet clearly explains that water "vapor" is sublimated through the PU membrane! Isnt it true that the vapor must condense on the inner surface, then sublimate through, and evaporate once again on the other side? Just like with goretex?
Seems they are insinuating the PU membrane is gas permeable. Is this a blatant marketing lie?
Thanks.

http://www.torayentrant.com/ent_dz/dermizax.pdf

Hi Richard

> Roger-Your question made me laugh because you were my source for 8.7 PSI. I couldn’t find any end user silnylon product for sale to the US ultralight backpacking segment which had a spec higher than 4.3 PSI. I knew that you were a fabric expert and you have a hydrostatic tester in your lab. I included your higher 8.7 PSI number because of your impeccable credentials.

Rotflmao!

OK, it seems we have a general problem with different silnylon coatings. In fact, my main source seems to have been supplying silnylon with different coatings and pressure ratings.

A couple of years ago I bought a quantity (maybe 60 – 100 metres) of rather good silnylon which had that high pressure rating, with a slightly 'wet' surface. But then the supplier changed the coating mill they were using and the modern stuff has a much drier surface, and I suspect the pressure rating has been going downhill all the way since then. I will have to test some of the very latest samples.

Apparently the switch in polymers used has made the difference. Why do they do this to us? Sigh.

By the way, I was convinced that the slight misting experienced with silnylon in heavy rain was a thin film of condensation on the underside being shaken loose, but if some of the stuff is only rated at 1 psi I start to wonder. Looks like Cuban Fiber may have to be looked at again …

This discussion of wearing silnylon to stay dry seems to relate back to my tests of SeaToSummit sil nylon "dry bags", made of silnylon. Performing a simple test, they leaked at less than 1psi overpressure.

My simple test was to turn the bag inside out, fill with water, and note at which depth water was seeping through the nylon. My own standard for a dry bag is a one foot submersion. The STS bags failed miserably, leaking from about 6 inches down, to the bottom of the bag, which was leaking like a sieve. So, no, some silnylon is not very water resistant.

For anyone interested, I went with SealLine StormSacs and Montbell Light Dry bags, both did not leak a single drop (literally) when filled to the brim with water.

I get silicone coated nylon from at least 4 sources.

One of the issues with silicone coatings is air pollution.
Dupont has figured out a way to recapture the solvents used
in the process so it meets EPA standards. Another maker
has gone to using a blend of silicone and urethane so a
different solvent can be used to meet EPA needs. Fabrics
from overseas probably don't worry about it. I get my
silicone coated fabrics domestically.

The only
test for waterproofness I have done (other than trying to blow or suck air through, which seems to be a pretty good guideline for waterproofness) is using the garden hose
which comes from a tank up the hill with about 150 ft of
vertical distance- enough head you can't keep your thumb over the end of the hose.

If I hold any of the nylons with a .25 oz. silicone coating
or a .75 oz urethane coating over the end, I will see many
beads of water form on the outside of the fabric. It certainly doesn't spray through like Epic, Quantum or other
DWR fabrics.

If I use a 1 oz coating of urethane on 70d ripstop, maybe
one drop or two will find it's way through.

If I use 1.5 or 2 oz. coatings of urethane on 210d nylon,
none comes through. Goretex is similar.

One thing I am curious about is the vapor transfer of eVent
compared to 2 layer Goretex XCR. I have seen comparisons
of 3 layer XCR and eVent that were a factor of 27 to 21. I
also know that the 2 layer goretex has improved vapor transfer over 2.5 or 3 layer goretex. It may be that 2
layer xcr may be very close to eVent.

And a note to Ryan-
contact me so I can make you some bivys and stuff. ;^)

Dave

I bring a propore jacket and no wind shirt. The jacket does triple duty as a rain jacket, wind shirt and bug shirt. As a wind shirt and bug shirt, it is a bit clammy, but effective. Using a light weight rain jacket in this manner is about as light as you can go while providing decent protection from rain, bugs and wind.

If you bring a wind shirt anyway, then the wind shirt may double as a bug shirt (I asked about this a while ago and most people believe that this is the case). If the chance of rain is low, then you could just throw a light poncho in your pack and get down to about the same weight.

If you don't need a bug shirt, then a poncho could work as both a wind shirt and rain protection. This would be the lightest arrangement I can think of. I wouldn't want to hike in a poncho to protect myself from the wind, but if I'm sitting on top of a peak and the wind is strong, then this could keep me warm. I've often run across this situation while day hiking (feeling warm all day until I sit and eat my lunch at the top of a mountain). The more annoying scenario I can imagine is making breakfast and having to fuss with the messy sleeves of a poncho. But, such is the price of using the lightest rain (and maybe wind) gear around.

I use a SMD Gatewood Cape, which is more or less a poncho. It weighs 11oz, and covers the weight of shelter, pack rain cover, and raincoat. I wear Marmot Precip bottoms and a Montane windshirt for outer layers with the cape. This is my kit for forested elevations in the Washington Cascades.

If I were hiking the coast in winter conditions, I would opt for a rain parka (Precip) and a double-wall tent. The cape outfit would probably make it, but wind-driven rain is the problem and I'd just put up with the extra weight of jacket and tent.

You need both, carry the heaviest, biggest, most waterproof jacket you can find, youll need it. End of story.

For years, not being able to afford quality WPB rain gear, I relied on a poncho. This was in Montana which experiences a much drier clime than the Pacific NW, and using a poncho was the perfect choice. After moving to the NW, I felt compeled to follow the crowd and go Gore-tex. I never felt so miserable! The steam, the condensation; yikes, I felt I had gotten as wet as if I not been wearing anything! So now I'm back to the old reliable poncho, as I like to feel vetilated while hiking. I've also recently started to pack a small, lightweight umbrella (~ 6 oz) for those occasional short summer showers. The only thing I'd change would be to purchase the Gatewood cape.

An old thread, but I just noticed a few points.

@Brett
afaik, your DIAD doesn't use Toray Dermizax, which is a membrain, but Toray Entrant DT which is a microporous coating (but probably not consistently enough to get noticable air-permeability.

@David Olsen
eVENT compared to 2-layer GTX XCR: if you look to the RET ratings for these fabrics, you get something like this
3-layer eVENT RET 4
2-layer XCR RET 4 or a bit less
(paclite RET 4)
2-layer eVENT RET 2,7
(GTX pro shell RET as low as 2,5)

I just wonder if these numbers mean anything given the fact that vapor needs to be adsorbed in almost all gtx variations.

Since you guys are discussing ponchos…
I am testing this poncho/tent combination. At the moment it is made with PU coated rip-stop nylon, my sample is 877 g (30.94 oz) plus stakes (6) and hiking pole. As you can see the poncho is the fly for the front of the tent. Any comments ?
Franco
Luxe pictures here http://www.luxeoutdoor.com/eng/catalog-topic-gallery-view1.asp?id=821&selfpath=/12/125

We know you're not going to give up your beloved Rainbow for this. :-)>

Perhaps if it were made of a lighter fabric. How does it perform as a poncho?

Kevin you are too clever by half. ( not sure what that means, next time I have a Guinness I'll wok that one out)
The poncho thing does not really inspire me ( Montane don't make ponchos) and I really doubt that HS will go down that way, but I am aware that some really like it. Luxe sent me a pair of rain chaps also, they are just over 3 oz. I estimate that the poncho/tent/chaps combo will be just under $150 US. My point is to see if there is a market in the US for this non-ultralight but nevertheless versatile and affordable gear.
Next year, if there is some interest, the range will be made out of silnylon, around 20-30% lighter but a bit more expensive.
This is an opportunity for some of you guys to suggest the design features that you like.
There is some nasty weather out there today so I am about to take my Montane eVents (top and bottom) for a walk.
Franco

Franco, I'm really imprerssed by this design. It's something completely new, and thinking outside the box. And by the looks of it, very weatherworthy. If it was designed with silnylon it would be just what I wanted.

May I ask how the back end is held up? A small pole, I think from the Luxe homepage, right?

Is the shelter available to purchase?

Miguel, the bottom end is propped up by a 14" strut that pops into place as you stake down the back middle guyline.
For the moment the Luxe products are designed for the Chinese market where price is more important than high tech or style. Think SD ClipFlash Light and not Akto.
BTW, they also make mountaineering tents but they look like everybody else's products.
Having said that the material used for the Rocket are more than adequate for 3 season use.
It is not in production as yet but it is due, as stated on their web site, to be ready in September.
Definitely very well protected against strong even wind driven rain, but I would not trust this type of design on an exposed site. Mind you ( I have not tried this as yet) but it could be possibly pitched lower to give it a bit more wind resistance.
Franco