Waterproofing a wind shirt

[Miguel Marcos]

Is the idea ridiculous or feasible? I have a Marmot Windshirt. It does a decent job when it's there's water in the air or the drops are small but it stops there. Is the idea of giving it a Nikwax treatment or similar feasible or will I kill the breathability of or otherwise ruin the outer material?

What I'm looking to do is to take the windshirt and a MB Thermawrap vest in place of Marmot Precip and Micropuff. I can knock off almost half the weight of the latter combination.

[Richard Nisley]

Miguel,

It is not feasible if you have a version of the Marmot Ion that is breathable. The 2006 model was not breathable according to many posts to this forum.

The pore sizes on breathable windshirts are made large enough to pass 1 to 5 CFM of air. At or below 5 CFM, most people cannot perceive wind through the material. This level of porosity optimizes the contrasting objectives of maximizing moisture transfer out from your body and minimizing wind transfer in. A fabric with porosity that results in 5 CFM generally results in a waterproofness level of about 2.6 PSI which will block drizzle but not rain. A truly waterproof garment is typically rated with a waterproofness level of 25 PSI or higher.

If your windshirt "wets out" then a DWR should be added for water repellency but it won't make the windshirt waterproof. Put an arm under a faucet and run water on it for a minute. If the water didn't bead up and roll-off the surface, then a DWR should be added for water repellency.

[Miguel Marcos]

Many thanks, Richard. I appreciate the response.

[Eric Blumensaadt]

I have two "sun shirts". One a Cabela's Guidewear shirt, the other a nearly identical REI Sahara shirt. Both have very tight weaves. I think they'd be OK for a marginal wind shirt and I'd "waterproof" them by:

1st > washing them in NikWax waterproofing & drying in med. heat

2nd > next spraying the shirt with Techron DWR.

That's about as much ass you're going to get, short of painting them with Seam Seal or a Silicone/mineral spirits mix. (hee, hee)

[Richard Nisley]

Eric – I also have some Cabela's Guidewear shirts. I agree with you that they are very tightly woven and would work well as windshirts. My informal breath test results in me estimating that they would fall into the mid range of windshirt's 1-5 CFM. You can't make Guidewear shirts more "waterproof" with a DWR but you can make them more "water repellant". I know that is what you probably meant but other BPL forum readers may misunderstand your advice.

The water repellant property is primarily determined by the surface tension of the fabric. This is what you alter with a DWR. The waterproofness property is primarily determined by the fabric weave. After market DWRs (wax, fluorocarbon, or silicone) don't typically alter the pore sizes between the threads enough to have a measurable improvement in waterproofness. Nextec Epic is a special manufacturing environment only case in which the waterproofness level can be permanently modified as well as the water repellency.

Nikwax is a wax based DWR. It does not enhance the Nikwax effectiveness to dry it with medium heat. This is a very environment friendly and effective DWR aside from its abrasion resistance. Its abrasion resistance is only about 60% of the fluorocarbons.

Techron is a fluorocarbon DWR. It significantly enhances any fluorocarbon DWR's effectiveness by drying the garment in medium heat for an extended period. There are large number of good DWRs in this class, in addition to Techron, including Grangers and ReviveX.

You should select one option or the other rather than mixing them. The second type that you attempt to apply would not be able to bond to the material.

[EndoftheTrail]

If a fabric isn't truly waterproof to begin with, all the after-market spray's and wash-in's in the world won't make it so. Don't be fooled by the "waterproofing" label.

If mere spraying can truly waterproof a windshirt, we would ALL be happily wearing 3 oz. waterproof/breathable rain shells! There's a good reason why this hasn't happened — so save your money.

[kevin davidson]

The more practical method of making your windshirt more water resistant is to seal the seams w/ a sealant. The fabric itself, will eventually wet out but the seams are the first point of leakage in a windshirt that has good DWR. I echo others above in stating that it's a waste of time and fabric to make a windshirt fabric waterproof. Akin to trying to get a pig to fly—it's unnatural. A garbage bag over your head would be more effective. Need I continue…?

[Doug Johnson]

Get this!

Montane Featherlite H2O

Light as a windshirt and truly waterproof. You'll need a hat, but you'll always love this waterproof windshirt- the lightest waterproof jacket on the market!

Doug

[kevin davidson]

If it had a hood it would be dangerous. But it's not particularly breathable–it's really sort of a b-astard in the category. I wish more UL jackets had the pronounced droptail of this garment, though.

One should read Don Wilson's review of it on this site—
http://www.backpackinglight.com/cgi-bin/backpackinglight/montane_featherlite_h20_spotlite_review.html

Doug—have you turned Montane pimp, or something? :-)>

P.S. it's become hard to get many Montane garments in the U.S. You'd probably have to order this from a UK retailer. But easier for Miguel of Iberia.

[Christopher Plesko]

Yea no hood is an issue although for cycling I'm not sure it matters? I might order one up if I can find one in a not hideous color. Not ready to ditch my modified DIAD yet though.

[Richard Nisley]

Kevin – Very good advice, but there are some related seam sealing subtleties that bear additional discussion.

I have water repellency augmented all of my windshirts which include: the Special Forces L4 Epic, Patagonia Houdini, Montane Featherlite, and Wild Things Lite.

For testing I used my home shower set to maximum force. I wore a windshirt in the shower with a long sleeve cotton T shirt underneath to determine if there was initial leak points that occured before the general fabric itself leaked. I then seam sealed those leak points, waited a day, and then tested again.

The first windshirt I augmented was a Patagonia Houdini. The general leak sequence pattern I experienced for all of my windshirts was 1) ++++++ the zipper, 2) ++++ the wash instructions and hang loop at the neck, 3) ++ the upper seams, and 5) + the material itself. The Houdini uses a silicone encapsulation similar to Epic and so I used Silnet on this windshirt. I did the zipper and all seams. The zipper experiment worked great but, I discovered two problems doing all of the seams: 1) the Silnet showed through the shear Houdini fabric and made the jacket seams look soiled and 2) the Silnet seams were uncomfortable to my skin when I didn't have a shirt on under the windshirt. All my subsequent windshirt augmentations focused only on the low effort/ high return zipper fabric and hang tag seams which were consistently the first places to leak on all of my windshirts that I tested.

The fabric zipper sealing augmentation technique that I used bears emphasis since I have never seen this technique in print. Completely close the zipper and turn the windshirt inside out. Use Silnet to completely cover the zipper seam, the zipper fabric, and the zipper teeth. The zipper fabric will permanently absorb the Silnet as apposed to just layering on top but Silnet will not permanently stick to the plastic zipper teeth. The zipper will open and close easily and any excess Silnet will just flake off the teeth in little granules. I used an old tooth brush to quickly remove the granules that flaked off on the first few initial openings and closings. The zipper fabric now keeps out water just like an expensive water resistant zipper.

I use Silnet but Seamseal should also work on non Epic fabric seams. I haven’t tried Seamseal on a zipper but if someone tries this experiment on an old windshirt, please report your test results. Also, if anyone else does a windshirt leak sequence test, please report if you discover a sequence different from what I experienced.

[Richard Nisley]

Doug – Light as a windshirt – YES. Truely waterproof – NO. A hydrostatic head of 1,300 mm is only 1.8 PSI.

This Montane material has a waterproofness level of 1.8 PSI which is the same as Nextec Epic 4 Summit nylon. Interesting enough the Montane's JIS L1099 – B2 breathability rating is the same as Nextec Epic 4 Summit nylon… maybe it is?

By contrast eVENT EV121: 112 g/ m2 weight with 40 denier nylon on the face has a JIS L1099 rating of 21,997 versus 6,000 for this jacket. In other words, the Montane jacket breathes less than 1/3 as well as eVENT does and well designed windshirts breathe better than eVENT. eVENT's hydrostatic head is 39.8 PSI versus 1.8 PSI for this Montane jacket. Truly waterproof, according to the US Government, is 25 PSI.

[Doug Johnson]

Hi Richard,

I've used my Montane Featherlite H20 for about 6 months and living in Washington, I experience pretty consistent rain. While I certainly wouldn't take it up Rainier or use it at sea, it is defintiely waterproof enough for extended rain showers. It's fended off many downpours and I've been pretty darn dry. At least as dry as in my SD Isotope or other PU jackets I've tested.

Now, I wouldn't subject it to the same conditions as my Montane Quick Fire eVENT jacket. That jacket is way more stormproof, and also FAR more breathable. But I use the Featherlite H2O as raingear and in my opinion and experience it's legitimate in that role.

I hear you on the waterproofing tests, but there must be more to the equation than just hydrostatic head tests. The field experience of both Don Wilson and myself would suggest as much.

My Epic jacket is not NEARLY as waterproof as this jacket. Not even close.

Cheers,

Doug

[Jason Brinkman]

I think we need to have BPL line up all the popular windshirts each year, and give us hydrostatic head and MVTR breathability for each. Ditto for lightweight 'rainwear'. Then someone can explain what a given hydrostatic head will protect us against, and what other factors come into play. The 1.8 psi seems pretty weak compared to the 25 psi military rating, but perhaps 25 psi is significantly more than necessary.

[Doug Johnson]

Yeah, that's a great idea Jason- I'd like to see that too!

[Richard Nisley]

Doug – I agree that, "…there must be more to the equation than just the hydrostatic head tests."

My suspicion is that if you use an insulation layer under this type of jacket, the insulation acts like a bullet proof vest and spreads out the rain drop's energy so the drops don't penetrate the fabric. The only other possible explanation that I can come up with is that their published hydrostatic head rating for this jacket is too low.

Can anyone explain this apparent contradiction between the Montane Featherlite H2O jacket's real world tests and the hydrostatic head theory?

[Doug Johnson]

Hi Richard,

It's not the insulation layer. I've used this as a cycling jacket more than anything…with only a thin jersey underneath. Same story when hiking with it. It's rarely been used with insulation when in the rain.

I think the DWR coating has a huge effect. Water just rolls right off.

Hmm…

dj

[mark cole]

Hey Doug, is that the same , maybe newer version , as the Montane Hydra-lite jacket? Thanks in advance.

[Arapiles .]

Coincidentally I just went for a half-hour walk in my new Paramo Fuera windproof to see how waterproof it is (it arrived in the mail on Friday). It's been raining all day here (13 C and windy) and I'd noticed that the Fuera's DWRC seemed very effective when I was out in the rain so I thought I'd see how long it took to wet through. Paramo is owned by the owner of Nikwax so it stands to reason that it should have a good DWRC …

Surprisingly almost no water got through after a 30 minute walk – I had a small wet patch on each shoulder and one on each side of my chest, and the cuffs of my shirt were wet, presumably from wicking. There was a little spray on the inside of the hood and the shoulders but the majority of the jacket was bone-dry. So an effective DWRC can boost a windshirt into emergency rain-wear. However I suspect that it would have leaked at pressure points, like under pack straps if I's been wearing one. Nonetheless neither my Patagonia Houdini or my old patagonia Pneumatic would've done as well.

Just to point out though that the Fuera is comparatively heavy at 290 grams!

[Michael Davis]

I has been my experience that a windshirt is a windshirt and raingear is raingear.

Maybe the closest material that can serve both purposes is eVent. However, eVent doesn't breathe as well as a proper windshirt, its heavier and it costs a whole lot more.

I use a Montane Light-speed windshirt (hooded, full-zip @ 5oz.). While it is a fantastic windshirt, it is definitely not raingear, not even a little bit.

Personally speaking, any rain jacket is way to non-breathable for me; my rate of prespiration can match any thunderstorm :~( Therefore, the poncho is my raingear of choice; breathable and lightweight.

[Eric Blumensaadt]

Richard,
Good reasoning. The Techron won't stick to NikWax treated material. I withdraw my 2-step treatment recommendation with NikWax.

So I'd just go with Techron alone or, better, so I've heard, is Revivex from WL Gore.

I do know some bicycling wind jacket/shirts are made with highly water repellant fabrics like you mentioned, with no DWR surface treatment. (Nextec?)

Eric

[James Pitts]

I tried waterproofing the seams of a windshirt I got on closeout. It worked fairly well but it did add a fair amount of weight to the shirt. Also, I didn't find the jacket to be nearly as "breathable". I still like the DriDucks jacket (or just getting wet if it's a warm rain).

I'll add on edit that the DriDucks jacket IS a windproof jacket… said another way…

Windproofing a rain jacket? vs Waterproofing a windshirt? (hehe)

[kevin davidson]

It's now possible to come in under 10 oz., carrying both a dedicated windshirt and a dedicated rain jacket. I think this fact alone derails serious consideration of trying to H2O proof a windshirt. For now…

But just wait for the next generation of DWR currently under development—-all the water repellancy that you initially get from today's best DWR but a far more durable and abrasion resistant treatment than is currently available.

http://www.outdoorsmagic.com/news/article/mps/UAN/4690/v/2/sp/

[Kenneth Puentes]

Based on the experience that some of you have with the Featherlite H2O, could it sereve double-duty as a windshirt and sole rain jacket for summere use? If yes to summer use, any sense how much futher into fall/spring it could comfortably used in this fashion? Generally would have light/mid weight base later beneath and if necessary, insulating layer as well. Feedback greatly appreciated.

-Ken

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