Cuben Rain/VBL Pants

[Dan @ Durston Gear]

Using durable 1.2oz Cuben (CT3.5K.18), 3M Tape and the simple rain/wind pants pattern from Quest Outfitters, I whipped up these cuben rain pants. I made them partially to save weight, but mostly because I'm sick of rain pants that aren't totally waterproof. I want to be able to dig a snow cave on my knees for 2 hours and not have water soak through, so I opted for non-breathable cuben.

Materials
1) CT3.5.18 Cuben – I ordered 2 yards (from Zpacks) and have about 2/3 yd left.
2) 1/2" 3M 3495PC Tape – I have a roll from Sailrite.
3) 3/32" Shockcord – Seems a bit light, I plan to switch to 1/8"
4) 2 Eyelets – I used the eyelet kit from Quest.
5) Medium Sized Toggle/Cord Cinch – From Quest
6) Cap thing for end of Shockcord – I had this laying around.

The pants were fairly easy to make. Using tape instead of sewing is a bit of a challenge to get the technique down, but if you work slowly and sometimes creatively then it all comes together quite nicely. I chose a safe size on the pattern initially but the pants were too wide through the hips/thighs so I cut open the side seams and took out a bit of material to slim the fit.

Overall I'm very happy with these pants. They fit great. I might switch to a thicker 1/8" shockcord at some point if I'm ordering other materials anyways to get a stronger waist.

And how much do they weigh? They tip the scales at mere 71.1g or 2.51oz. I think that's pretty darn good for durable pants that should last a very long time. I could have used lighter cuben but I want these to last.

[Andy Duncan]

Very nice, they turned out great. Thanks for posting the photos and details.

[Lawson Kline]

They Look Great. Nice Work.. Did you remake the cuben rain jacket yet?

[Tad Englund]

Dan, I would like a review after you use them- I have the same problem (wetting out) iglooing but I'm afraid that the cuben might wetout on the inside from persperation. Also, they look like a good fit in the picture but will they give you a "crack attack" when bending over repeatedly or kneeling for an extended length.
Nice work!

[Steven Evans]

Dan, those look fantastic! I just ordered the liberty ridge jacket and pants – hopefully mine turn out just as nice!

[ziff house]

I'd love to try those, if they can stand a bushwack it would be 'THE' alternative to heavy duty logger ones. Lucky they weren't white as i'm in danger of turning totally white with all thsi cuben stuff.

[Dan @ Durston Gear]

Thanks for the kind words guys.

Did you remake the cuben rain jacket yet?

No, I plan do that at some time in the near future using CT1K.08 and CT3.5K.18 reinforcement on high wear areas. I wanted to get the pants done first because I want to use these in the winter months, whereas the rain jkt likely won't be needed until spring. I'm going to add a few ventilation options to the jkt. I might add inner thigh vents to the pants.

I'm afraid that the cuben might wetout on the inside from perspiration.

This is definitely a possibility. The nice thing though is that it's predictable (ie. directly related to my exertion level and how long I wear them). So I can confidently wear my down pants inside of these for shorter time periods at lower exertion levels. As I use these pants, I will get better at predicting how long I can wear them and stay relatively dry. Non-breathable pants aren't perfect for everything, but they do have some neat applications.

In the summer months, I picture myself wearing only these while hiking in the rain (hence I choose black) so even if I do get clammy/wet inside it won't matter. The benefit here is that I can not wear my hiking pants so they stay dry. Then in camp I could dry these with my bandana if needed and then wear them over any additional layers I need to keep warm. I wore them around the house for a few hours yesterday over my hiking pants and it took several hours before they started feeling a bit clammy.

Will they give you a "crack attack" when bending over repeatedly or kneeling for an extended length?

The pictures don't show this (I guess they're laying funny in the first picture) but the back of the pants is higher than the front. When I made these pants I started with the waist way too high and the inseam way too long. Then once I had the pieces together and I could try them on, I choose a suitable waistline and inseam length. The back of the pants is about 2" higher than the front so I think it will fair reasonably in this regard. With that said, next season I plan to use a longer rain coat that gives me more overlap with the pants than my current Marmot Mica does.

[Henk Smees]

Hi Dan,

First of, I’m impressed – those pants really look great but…… I would be worried about condensation. You more or less addressed this in your previous post where you said it is either not too bad or you can live with this (given the period of time you’ll be using the pants, it’s either one or the other – if I read this right).

Now, I have some CT2K.08 and was going to use this for making a skirt + chaps instead of pants because of the fact that condensation does worry me. Your pants and explanations have made me thinking though; since I do want to minimize condensation as much as possible, I’d rather stick with the skirt/chaps-combination idea. Could you think of any reason NOT to do this?

Another question: You said the Cuben you used is CT3.5.18 and you bought it from Joe. According to Cubic Tech latest on-line specs for CTF3, this is no longer available – neither in K, nor in HBK (Hi Bias). They only seem to have CT2K.08, CT3.5K.08 and CT5K.08 (in the thinner Mylar line) now and CT9K.18, CT2HBK.18 and CT5HBK.18 (in the thicker Mylar line), so I suppose the Cuben you bought from Joe might be from an earlier product line. Could I be right?

The reason of asking is because I’ll probably need some more Cuben for several projects and I want it to be as abrasion and puncture resistant as possible. Knowing the last two digits at the end stand for the thickness of the Mylar film, I want to go with 18 – Am I right to believe the lightest version of this stronger Cuben would be the CT2HBK.18 at 44.6 gr/m2? If so, I’d probably order some and make the skirt/chaps from this, saving the CT2K.08 for something else.

Edit: Next in the line of 18 Mylar would be CT5HBK.18 and that would weigh 68.5 gr/m2 – far too much.

[Dan @ Durston Gear]

I wore these pants today on the ski hill here in Whistler underneath my normal ski pants just to try them out and see how soggy things got. What I was wearing was:

Bottom: Thin baselayer + cuben pants + WP/B Shell pants (non insulated)
Top: Thin baselayer + FA down vest + eVent Shell Jkt

The conditions were warm (25-33F) and wet (raining or snowing).

The results were definitely interesting. For most of the day I was skiing pretty hard and I felt significantly more damp/clammy on the upper half of my body than the lower. I believe this was because even though I had an eVent shell on, my upper body was generating a lot more moisture than my lower half, so the eVent was falling behind faster than my non-breathable cuben pants were. After skiing for 4 hours, I felt damp on the legs, but not totally soggy. I was definately more dry than I normally am because my WP/B shell pants aren't actually waterproof anymore so on sloppy days like this my legs wind up pretty wet.

What I observed at this point was that being damp while wearing a VBL (vapor barrier layer) is far more comfortable and warm than being damp without a VBL. I was damp, but I wasn't feeling a chill.

At the end of the ski day I had to ride a few chairlifts and then walk 30 minutes home. Over this time period, my upper body dried off pretty well thanks to the eVent, while my lower body was steady at moderately damp. I was pretty happy being damp in the VBL pants…more so than expected.

Based on this experience, I think I am going to be quite comfortable and warm hiking in the rain in these pants. The main thing is not to wear too much stuff underneath that I don't want to get damp. I wash my boxers every evening anyways, so if it's a rainy day I can leave the hiking pants off and just wear boxers + cuben pants. Then once I'm in my tent or the rain has stopped I can switch to hiking pants. For shorter wear times (ie. running out for a pee) I can just layer these over whatever I'm wearing.

Henk: Regarding a skirt + chaps versus pants, the main advantages with pants is that they are simpler (1 piece vs. 3 to keep track of and put on) and they might be more waterproof (ie. perhaps if you're sitting down rain may land on your chaps and roll under your skirt?). The pants are also a bit less weird if that concerns you. The skirt + chaps would definitely breathe way better though. It mostly depends on your goals. A skirt & chaps is likely simpler to make.

Thinking of how well my CT2K.08 stuff sacks have faired, I would say you'd likely get a season of use at most out of CT2K.08 rain pants. This stuff is strong (ie. you won't get huge tears) but you can get small holes and pin holes fairly easily since the 0.08 mylar is pretty thin.

The 'latest online specs' from Cubic Tech that you are looking at are actually quite old and pre-date the existence of CT3.5K.18 (1.26oz) and CT5K.18 (1.5oz). A lot has happened in the last year. I think they posted that in late '09. You can buy the black 1.26oz stuff from Zpacks like I did. He's out of stock right now but he expects it in mid-late January. The 1.5oz stuff is in stock now. If you don't care about color I would just go with that since it's barely heaver (1.26oz vs. 1.43oz) and it's even stronger. Black is not see-thru though like the other colors are.
http://zpacks.com/materials.shtml

[Henk Smees]

Hi Dan,

Your skiing experience is very interesting indeed – might make me change my mind about the skirt/chaps vs. pants question and, in this respect, I certainly agree on the pants being simpler. I also admit that the skirt/chaps combo will be easier to make, but that wouldn’t be a reason not to go with these (the fact that something is more difficult to make, wouldn’t make me decide against it).

You mentioned some other advantages of the pants (being a VB, more waterproof and the combo looking weird). First of…… I’m not at all worried about the combo being “weird” – my main concern is about my gear being functional, multi-use and as light as possible; furthermore, I want to be comfortable and safe. Whilst weight is important, I’d be willing to do concessions -as many as necessary- when it comes to comfort and safety, but certainly not because something might look “weird”.

In respect to VBL, I have no experience at all so I can’t judge this; I have read a lot about it though and it looks like people have different opinions – it has many detractors but others believe it’s great. Spending a lot of money on an item without knowing the result doesn’t appeal to me but, having said so, if I don’t try, I’ll never find out. Don’t know what to do.

With regards to pants being more waterproof: I use a very short poncho (so it doesn’t impede me seeing where to place my feet), but it’s long enough to cover myself when I would sit down whilst raining.

I’ll definitely have to give this some more thoughts but the fact that the skirt/chaps combo breathes a lot better is something that still sounds like a great advantage to me.

After your explanations about your CT2K.08 stuff sacks -thanks-, I’ll definitely save my CT2K.08 Cuben for other projects (fly of my double wall TFD Tent and a few minor items), meaning that I’ll have to buy some more (with .18 Mylar film). In your opinion, wouldn’t the HBK be a lot stronger than the K version? Having said so, if specs haven’t changed, the lightest HBK with .18 Mylar would be CT2HBK.18 (at 44.6 gr/m2), whilst the two versions Joe has (CT3.5K.18 -1.26oz- and CT5K.18 -1.43oz-) weigh 42.6 and 48.4 gr/m2. In each case we’d be talking about .18 Mylar film, but in the lighter K version the Dyneema thread inside would be 3.5K (against "only" 2 in the HBK) – in the heavier version it would even be 5K (which is supposed to be 2.5 times stronger than the 2HBK version). What I’m trying to say is that I don’t know what kind of Cuben to use for my projects: 3 Dry Bags (20 L. each) for my TFD pack 2.0, a groundsheet/tentfloor for my TFD tent and, probably, skirt/chaps + a new poncho as well (something similar to Roger’s Silnylon Mountain Poncho).

[Dan @ Durston Gear]

For the cuben used for your rain gear, I think the most important thing is having the .18 mylar. CT2HBK.18, CT3.5K.18 and CT5K.18 would all likely work quite well. I believe the mylar thickness is the main determinant of abrasion durability, whereas the amount of spectra mostly determines how strong the fabric is which is key in applications like a tarp where abrasion is low, but tension stress is high. In rain gear, the actually pulling/tension on the fabric is quite low, so the lightest .18 mylar fabric would likely be fine. Even the lightest option being discussed here is incredibly strong….far stronger than CT2K.08, which is already quite an impressively strong material.

So of these three cuben options, I personally would go with one of the latter two options because you can buy them by the yard, whereas no one but Cubic Tech sells CT2HBK.18 so you'd need to buy a full 9 yards from them. Also, high bias cuben is significantly more expensive as I recall. I think it's around $35/yd. I don't think this would be money well spent versus regular cuben. Pretty much no one has done anything with high bias cuben on this site because there's not really a good reason to spend the extra money in most applications.

Regarding your list of projects (dry sacks, tent floor, rain gear), I personally would use 1.26oz cuben for all of this. I think it's great for all of those applications. All of these items are primarily going to test the abrasion resistance of the material, not the out right breaking limits, so I don't think there would be a significant difference in performance between any of these variants. Accordingly, I would select the cuben variant based on price, color preference and ease of acquiring. The only exception to this might be if you plan to sew some of these projects. Sewing puts a lot of stress on small areas, so having more spectra is always good thing. If you plan to sew, I would go with CT5K.18 just to make sure those stitch holes stay as small as possible.

[Henk Smees]

Hi Dan,

Many, many thanks for your extensive explanations. After reading numerous posts on this forum, it was clear to me that I had to go with .18 Mylar (because of its far superior puncture and abrasion resistance). It’s obvious as well that Cuben will become stronger as the spectra inside becomes thicker – I just couldn’t make up my mind about which Cuben to use. I’ll follow your advice and go with the CT3.5K.18. Thanks again.

I didn’t know HBK would be THAT much more expensive than “ordinary” K and it looks like the CT3.5K.18 will be stronger than CT2HBK.18 and a little bit lighter as well – 2 gr/m2 :). If need be, I can always use patches of the 3.5K and glue these diagonally on the high stress areas.

I’m not planning on sewing, but if I were to go that road, I would glue a 1” strip of the same Cuben over the seam to waterproof same and this would increase the strenght as well. With regards to buying directly from Cubic Tech, I have no problem with buying a full length of 9 yards; I feel like having enough projects to be able to “spend” it all. Having said so, I like the black color version Joe will have back in stock soon, so I might as well go with that. Since he sells some other items I’d like to buy, I wouldn’t mind waiting (if it doesn’t take too long) and save some on transport costs (very expensive to get things shipped to Spain).

Some other thoughts: Since I’ll be buying the 3.5K.18, I’m thinking of using this for the fly of my TFD tent instead of the 2K.08; I suppose this would make it bomber proof. I know people have made -successfully- tarps & tents out of CT2K.08 but, for a little weight penalty, I guess the 3.5K.18 will be that much stronger that it’ll be worthwhile – I think. BTW: The inner will probably be made of nanoseeum.

Anyone who’s willing to share ideas?

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