Cuben fiber mountain poncho

[Jan Rezac]

Here is my latest creation: a poncho based on the Roger Caffin’s “mountain poncho” design made of cuben (big thanks to Roger for sharing his pattern and instructions).

Material is the CT2K.18 (1.0 oz/sqyd) cuben from zpacks. While it is not the lightest cuben out there, it is the first one with double-thick foil layers what makes it truly waterproof even after some wear. This had been shown here by Richard Nisley and my tests confirmed that. At the time I was buying the fabrics, it was the only really waterproof option at this weight range. My previous poncho was made of 20D silnylon which had claimed HH of 1500 mm – it was waterproof when new but started leaking badly after something like ten days of use. Now there are some nice light sil/PU coated fabrics that are also waterproof enough but I guess cuben will last longer.

Design. I’ve modified Roger’s pattern slightly in some details (rounding some lines) and I make the poncho and the sleeves a bit longer. I’m also using a water-resistant zipper instead of snaps (which I had on the previous one and found it difficult to keep them organized). The zipper closes from top so it’s possible to zip up the collar and leave the rest open “cape style” for ventilation. There is also one snap (see the first picture below) that can hold the poncho in place without using the zipper.

Details. The double-sided tape makes it easy to make neat details – e.g. the drawcord tunel and visor on the hood are laminated from inside without sewing through the outer fabrics. All seams are taped – I made my own seam tape from 0.5 inch wide double-sided adhesive tape (from zpacks) and the fiber-free foil cut from the edges of the cuben. It worked really great and is as light as possible.

Working with cuben. Before I started, I was really worried of sewing the tightly curved seams in a material that has practically no stretch. In the end, it was not that hard, but only because I made a very accurate pattern in computer (which I tested successfully on the silnylon prototype). For things like sewing the sleeves into the oval holes in the poncho, every millimeter matters.

Weight is 177 g (6.24 oz) including a 4 g cuben stuffsack. 20 g lighter than the one made of 20D silnylon.

I have yet to see how it works. I’m sure it will be waterproof and I’m curious how it will handle the condensation – cuben tarp stays much drier inside than silnylon. I am only somewhat concerned about it being noisy but it should get better when the cuben wrinkles more (I’d love to see cuben with TPU membrane instead of PES).

[Monte Masterson]

Very nice Jan

[JCH]

Wow Jan.  Just…Wow!  That is beautiful. Please keep us informed on how it works out.

[Roger Caffin]

Yeah, feedback when you have tried it out would be great!

Cheers

 

[Kyle Baker]

This looks great Jan. Thanks for posting and look forward to the field reports.

[Bob Moulder]

Beautiful work, well executed project!

Looking forward to your reports after using.

[Ryan K]

That looks amazing Jan!

How’s it work with the jacket tucked into the pack, just covering your pack Packa-style?

A draw cord at the waist, pulling it tight under the pack and around your waist, should make it pretty wind-proof?

[Jan Rezac]

First field report. Finally, I had a rainy trip. It was an overnighter with about five hours of walking in moderate but continuous rain and I can say I was never so dry under such circumstances. I had very small backpack so there was plenty of ventilation (the poncho gets tighter but still perfectly usable with backpack sized for long backpacking trip but it won’t fit too large pack). The weather was quite warm and calm so I had the zipper open part of the time. There was some condensation in the sleeves (which I used only about half of the time) but at the torso, not only me but also the inner surface of the poncho stayed dry. A friend I hiked with had exactly the same poncho but made of the silpoly PU4000 fabrics, it worked equally well but it got wet on the touch even in the torso area – I’d attribute this difference to the higher hydrophobicity of the cuben.

Performance of the material. The cuben is absolutely waterproof as expected. I was worried of the noise but, to my surprise, it is not an issue in real use. The poncho is almost as quiet as one made of fabrics and when walking, I simply didn’t notice it at all. The only drawback is the stiffness of the cuben – a poncho made of woven fabrics drapes much better. It is, however, more esthetical rather than functional issue (maybe on the contrary, as the lack of drape may improve the ventialtion). We had a couple of short off-trail sections including some thick undergrowth. The poncho slipped through it reasonably well but the previous one made of slick silnylon handled bushwahacking much better.

Design issues. The only real issue is that it is difficult to start closing the zipper at the chin because it has to be done only by touch (visual control is possible only with head pulled inside the poncho and putting the hood on only after it is closed – this is possible but more complex). After a couple of trials it got easier, but it won’t be much fun with cold hands. However, I still prefer the zipper compared to the complicated closure with snaps and velcro. A two-way zipper starting at the bottom would be much better solutions but it’s not available in the #3 size. Maybe a one-way zipper starting at the bottom (for full, waterproof closure) combined with a row of snaps from chin to the upper chest (without any waterproofing flaps, to allow for simple use in the cape mode when full waterproofing is not needed) would be a better solution. The snaps could be kept closed under the zipper so switching to the fully closed mode and back won’t require closing or undoing them. This will be considered in a future version (which is, I hope, long time ahead).

Modifications to be added. I will, however, add two small mods to the present poncho. The first is to add some means of securing the hood rolled into a high collar. In all but the worst windy conditions, I prefer to not to use the hood but wear a hat (I’m about to make a simple waterproof cover for my wide-brimmed hat to be used with the poncho). This will allow keeping the hood out of the way and dry until it’s needed. Second, we bivy-camped on that night and I realized that adding several tieout loops in the right places would allow using the poncho as a mini tarp covering my head that would make using the bivy much more comfortable. It will also enable using the poncho as improvised door or additional wall for my flat tarp so I think it’s worth the few additional grams.

 

[matthew rangel]

That hood design looks way better than my OR Helium jacket. I can’t keep that hood on in a mild gust if my life depended on it!

[Paul McLaughlin]

regarding the zipper:  I agree on the snaps combined with zip idea. I have downloaded the pattern ( thx Roger) and gone as far as modifying it to the size I think would work for me and my pack, but haven’t gotten around to making one yet. But my strategy on the front closure would be the snaps and zip – or possibly velcro tabs and zip if I had issues finding plastic snaps I liked. I like the idea of a zip for big wind, and I also like the idea of the snaps for complete freedom of opening – open at the top, or the bottom, or in the middle just as it suits.

[Anonymous]

Looks nice, good job.

“Now there are some nice light sil/PU coated fabrics that are also waterproof enough but I guess cuben will last longer.”

Yes and no. Some cuben shines in tents, tarps, and shelters because of a combo of it’s crazy tensile strength per low weight and very low water absorption, but even 1 oz cuben has the Achilles heel of poor abrasion resistance/wear (though this form is definitely significantly better than the lower weight ones).

And eventually, it will start to go fuzzy, and once it starts that, it will start to hold onto moisture more and more.

Some of the new Sil/PU poly fabrics have a very high and durable HH, also very low moisture absorption, and moderate abrasion resistance, and with a poncho, there is not going to be a whole lot of difference in total weight between using a 1 oz/yd2 fabric and a 1.07 or even 1.4 oz/yd2 fabric.

Also, with fabrics that are at least primarily silicone treated on one side, it’s fairly easy and cheap to add more coating if it loses some WR.

Once Cuben starts to go fuzzy, there is not much to do, except maybe add a silicone coating to it as well. However, eventually that film will degrade more and more (especially without such a protective coating).  It’s really pretty thin, mono films being used. Such films will likely never compare to the abrasion resistance of woven fibers at similar weights.  There’s a lot of physics against it.

The main difference is the cost factor.  I have a Cuben tent and quite like it.  At this point though, knowing what i know, i wouldn’t ever make or buy any kind of cuben clothes for myself because i’m interested in long term durability and longevity of most of my gear.

All that said, your cuben poncho will probably last a good long while at good performance, unless you use (and by use, i mean actually wear it) a lot and do a lot of bushwacking type hiking.   But for occasional, periodic use, mostly on established trails–should be plenty durable and long lasting while maintaining it’s high waterproofness (but at 3 to 4x the expense of some of those other mentioned fabrics).

[Jan Rezac]

To those interested in making this poncho: send me a PM  with e-mail and I will send you the pattern. This applies to BPL members, the pattern is based closely on the one from Roger Caffin’s article so I don’t want to make it public without his consent. You’ll need access to that article anyway for additional information.

The pattern (in 1:1 scale) contains all the smaller parts, it is all pieces for the  hood, the sleeves and a pattern for cutting the holes for the hood and sleeves into the main body. The main body itself is large but simple and can be easily constructed as described in the article. One more piece is missing in the pattern, the zipper flap. It’s just a long stripe of the material and the actual dimensions will depend on the dimensions of the main body and on details of the opening.

The central piece of the hood, which was originally just a stripe of fabrics, is now divided into two pieces that form an extra triangle where they connect. This triangle is the attachment point for the rear hood adjuster.

I also provide an optimized layout of all the pieces including the body for fabrics 135 cm wide (that’s what I used), 305 cm of the material is needed. There’s a 10×10 cm square on the pattern you can use to check that it was printed in correct size (don’t ask how I learned to do this).

CAUTION! The solid outline of pattern is the cut line, the dashed line is the seam. There’s no issue with this for the actual parts, but the solid line is inside the dashed one in the case of the pattern for the holes. Cut along the solid line and ignore the outer dashed line.

When making the poncho, consider adjusting it to your size. I’ve already made the sleeves a lot longer than in the original pattern to fit my long arms. Next time I’d also make it wider. The poncho fits me well when I carry a smaller pack but it becomes tight with larger one, and you want some space for ventilation. You can always sew it narrower easily but not vice versa.

Next time, I’d also round all the corners of the seam connecting the front and rear piece of the body, it will be easier to seal the seams. My thoughts on the zipper are posted above.

[Adam Kilpatrick]

This looks great Jan; how has it been fairing?

Also, just wondering how tall you are and your approximate build? I’m 5’10 (178cm) and 90kg at my heaviest.

Did you do the mods you were thinking about? There is plenty of material there, so a fair bit of potential to supplement a bivy.

 

Cheers!

[Jackie Munro]

Disclaimer…I no longer do ultralight backpacking. I do however follow trends because I own a manufacturing company. We sell several outdoor product lines. But, I also have a store on Vancouver Island, and in the store (only) we specialize in custom outerwear from technical fabrics.We don’t sell our custom garments except locally, so thats not the reason for my post. We do sell excess technical fabrics online and its grown to be a niche part of our business. What I’m trying to learn more about is the needs of backpackers that sew their own clothing, without bringing in fabrics that you can easily access elsewhere. We want to only carry technical fabrics that are hard to find.Because of my own lines, we mostly have shells and soft shells, and base layers.  I was reading the post about this mountain poncho and saw that the fabric being recommended was Cuben. So here’s the question… Other than weight, would a breathable shell be preferable? I noticed a post concerning condensation. For example, I have been using a 2.1 oz./sq yd Polartec PowerShield Pro, that is designed to be an outer layer when paired with Polartec Alpha insulation. But, I’ve made super thin travel jackets for myself and others. The outer nylon face is fairly durable. Can’t speak to the lamination, which is polyurethane. But, my jacket has lasted well.  Would Cuben cause you to sweat?  What about Silnylon?  Help educate me to the needs of the ultralight do-it-yourselfer.  thanks!

[Adam Kilpatrick]

Yeah a breathable fabric would have some benefits, perhaps mostly in the hood and upper torso area. Though the idea with such mountain ponchos is that there are plenty of possible venting options built in and the fabric runs on the outside of your pack and pack harness, thus affording additional air gap vs a rain jacket that is tighter fitting and compressed against you by a pack.

Cuben doesn’t adsorb as much water on its surface as silnylon, so it can dry faster, condensation will also be less of an issue. But its very expensive.

Ripstop By The Roll do a very light WPB fabric that you might like to look at. I’m considering it for parts of a mountain poncho (though perhaps not on my first try). Its a 1.4oz fabric.

Their .74oz MTN 7D Ripstop Nylon might also be an option, particularly for the pack section, where durability is perhaps less of an issue. Its PU coated with reasonable breathability and reasonable waterproofness (HH 1000mm…good enough for a pack, particularly the vertical sections where HH isn’t as critical).

[Jan Rezac]

Adam already summarized it well. My motivation to use cuben (particularly this one with thicker foil layers) was that it was the only material available in this weight category that will last waterproof in the long term. A friend of mine made the same poncho out of silpoly/PU at the same time, so we’ll see how that compares (it was the only other UL material that passed the condition of being waterproof even after simulated wear, but the question is when the PU degrades).

It may be interesting to make the sleeves from a WPB fabrics (I don’t use the hood much, and I’d probably skip it next time). However, the advantage of a poncho is that when I don’t need to use my hands an I’m just walking, I do not use the sleeves at all and keep my hands inside, where there’s better ventilation. And if I had to use my hands more (eg. walking with poles all the time), I’d add some vents or pit zips rather than relying on a breathable fabrics.

[William N]

Great design. Well done.

I use a poncho as a rainfly, I fold panels in the front, sides and back ( if I don’t have a backpack to drape it over). Velcro. This way I get a good sized tarp, but a normal sized poncho. It’s a bit fussy all the sides. Different colors would really help)

What might work for you is a small loop of line or grosgrain on the hood. Then if you use it as a tarp, a line through the loop pulls the hood over the opening to keep out the rain. Two lines off two loops would be even better. The loops should be above the brim.

Also I found it impossible to put the poncho on while wearing my backpack. I could never get it to drape over the backpack. But I saw a French or Swiss BPL contributor’s poncho. He attached it to the top of the backpack just behind his neck (a couple of ties underneath) Then it was easy to pull it over him and also down the backpack. It also stores rolled up over the backpack. Not sure if your’s can do that (but don’t make it looser. I tried hiking in blowing wind and rain with my flappy poncho, even belted at the waist. I was more sail than than anything else)

[Terri S]

I joined this forum specifically for this thread/pattern. I have a “parcho” which I made out of silnylon, which I like a lot, but I really like the look of the mountain poncho.

I recently purchased some Membrane Silpoly from Ripstop by the Roll to make a 2nd parcho, but when I came across this posting I thought that I’d like to make something like the mountain poncho instead.

I did find a waterproof 2 way zipper, I replaced the original zipper in my parcho with this one, and it’s very nice to open it up from the bottom when it’s not raining hard.

[Justin Lafrance]

Fantastic, Terri. Do you have any photos of your parcho?

[Terri S]

I have a couple of pictures, but you can get a better look at the Parcho on its instructions page:

https://www.questoutfitters.com/10JuneParChoSewRedFileSz%20(1).pdf

This is my silnylon parcho

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