Cuben / Down Quilt

[Tim Marshall]

the .33 isn't going to get damaged like that. I think maybe a toe-nail could snag but it wouldn't cause serious damage, it might scuff the material. The scuff is all i have been able to do to it without trying to destroy it. Others who have used them in the field might have better insight than me. I haven't even had time to make myself one yet:)

-Tim

[Steven Evans]

Nia,
I can verify when I get home, but I don't think you would be able to poke a hole through the 0.33 cuben with your finger…if you did, you would definitely know it as it would take some noticeable force. I use the 0.33 for the bottom of my bivy with a pad underneath and it has held up fine. I would be more worried about my toenail catching one of the baffle seams then the cuben itself. That said, I wear socks when I sleep so my comment has no real experience.

In all honesty, I treat my Epiphany the same as I do any other bag or quilt (maybe I baby my gear more then others). It stays in a stuffsack in my bag and only comes out in my shelter. In the morning I pack it up and back into my bag it goes. Other then sleeping with it, it doesn't really get exposed to an environment that could damage it. Even if I dry it out during the day it just sits there – stay away from branches and thorns of course :)

[Bob Gross]

Most of us don't have any experience with cuben fiber, so we don't know how to think about it. What would it take to really puncture the surface? You've already stated that a finger won't puncture it. What about a ballpoint pen? What about a pocket knife? Or, can you compare its strength to some other standard material that we would know (e.g. men's cotton handkerchief).
–B.G.–

[Andy Berner]

I recently got a Zpack and Hexamid made of cuben fiber and its a lot stronger than I ever thought it would be. In all honestly I'm not even worried about it at all.

[Vick Hines]

Bill,
"What would it take to really puncture the surface?" Not much. In fact it can develop small holes at the ends of seams or pull points because the only thing holding the yarns in alignment are the thin films on each side. These holes will not become tears and are easily repaired with a small tape and Cuben patch.

"What about a ballpoint pen? What about a pocket knife?" A ballpoint will poke through without much trouble, but a knife is the real danger. The Spectra yarns are too tough to cut with scissors, but a knife will go right through. In fact I use razor knives to cut Cuben for projects. If that seems contradictory, remember that the films hold the yarns so they cannot shift easily. All the force of the knife edge is concentrated and that is more than the Spectra can take.

"can you compare its strength to some other standard material that we would know (e.g. men's cotton handkerchief)." Even with the caveats above. Cuben is lightyears stronger than a pocket handkerchief. I would guess that the bursting, snag tear and tongue-tear strengths are at least as high as 8 ounce Oxford nylon pack cloth (coated) or 10 ounce Cordura (coated), although I have done only informal tests.

What you did not ask about: abrasion resistance. Zilch. The films are rather delicate. Very rough rock can violate the films on both sides, but (this is important) will not immediately cut the Spectra yarns. However, it is possible to snag the yarns. Since they are so strong, they can start to pull out before breaking. I would keep it off rotten granite.

We can hope that someday soon a mill will combine fine yarns of Spectra with something like 10 or 20 D polyester and impregnate it with silicone. Now that would be just about the best.

[Steven Evans]

It's tough to describe a fabric in words (I probably can't!), however Vick has done a great job above.

Picture dental floss sandwiched between layers of saran wrap. Depending on what strength you purchase will determine the amount of layers. :)

That said, the questions about durability of "cuben fiber" in an application like this is really only aimed at the lighter weights, in particular, the 0.33 oz/yd we are discussing now.

I have a bunch of 4.01 oz/yd cuben fiber and you would need a very sharp knife to stab a hole in it. My sample pack came with some even thicker versions (not sure of their weights off hand) that are not listed on the cubic tech website, but they remind me of plastic cutting boards – probably stop a bullet.

[Lynn Tramper]

I find the puncture resistance of the 0.33oz/yd cuben to be similar to a standard plastic supermarket bag. It also has a similar look and feel, but the fibers add tear strength above and beyond a plastic grocery bag.

[Jonathan Haynes]

I, for one, would like to imitate this design if the specs are 'open source' as it were. Also, where are materials available? It'd make a lovely winter project.

[drowning in spam]

Check thru-hiker, quest outfitters and zpacks for these materials.

[Jonathan Haynes]

Thanks.

[Adam Kilpatrick]

Soliciting info from the "originals" that have cuben quilts from this thread; how many nights have you put on your quilts now? Do you think the .33oz is strong enough? Some pics of any failure points would be useful.

Thinking about using it as a shell in parts for a MYOG quilt.

[Peter Nash]

I made two quilt/top bags last year, using .34 Cuben for the tops. If I had to do it again, I'd opt for the .51. I had a serious tear on my 3 season bag after just a few nights. I repaired it in the field with some white Cuben repair tape, and that worked fine.

Here's a photo of the bags, and a close-up of the repair. The repair is hard to see because it's white repair tape on white Cuben. I bumped up the contrast to try to show the tape.

[Adam Kilpatrick]

That's interesting Peter…that doesn't look like its on a seam at all? How did you managed to do that?

I would have guessed the seams would be the problem, not mid panel after only a few nights.

Thanks for posting, nice looking quilts, I hope I can make one that looks as well constructed.

[Peter Nash]

I don't know how the Cuben got ripped. It wasn't a seam failure. I woke up with down in in my Hexamid.

The .34 Cuben is astonishingly light, but it can be torn, and a rip once started doesn't take much force to spread, evidently.

I don't know what the optimal weight Cuben is for a quilt or bag. I may have been unlucky. But my next bag will be one grade heavier, based on my single experience.

The repair though did work. How to do the calculus of risk vs weight saved is always interesting.

[Adam Kilpatrick]

"How to do the calculus of risk vs weight saved is always interesting."

Yes indeed, always a tough call.

[Tim Marshall]

The .33(.34 now?) is uber light. I'm planning to bring the Epiphany back this fall and I will be using the .51 material (maybe .53 now?). The .48 (what's it called now?) has 2/3 the spectra (dyneema?) of the .51 so for me that's a no brainer in durability and barely noticeable on the final weight.

I've seen a few of these come back over the years and other than minor sewing expansion at buckle points the fabric itself had held up well. A little tape has fixed those issues. The most beat one had .51 fabric and had been zipped in a tent. The biggest repair I faced were delaminated baffles from the days of taped KARO baffles.

-Tim

[Peter Nash]

Tim,

It's great to hear that your plans include bringing the Epiphany back. It was your Epiphany that inspired me to make my Cuben top bags. Definitely a learning experience for me, a lot of time involved, but challenging and fun.

I don't remember if my Cuben was designated as .33 or .34, but I got it from Zpacks early last year, and it was the lightest available. The bottom of my bags is 1.0 Cuben, or at least that's what it's now listed as at Zpacks.

Although the close-up photo of my bag appears to show sewn baffles, the black lines are actually black ink that I marked on the Cuben as a guide to taping. All seams over areas containing down were taped. Only the edges outside of the taped areas containing down were sewn. That was where I attached the bottom. I didn't want to undermine the vapor barrier with sewing needle holes. So far the taping has held.

I've been trending away from quilts and toward top bags because the draft issue with quilts. My bags were designed to accommodate a Neo Air mattress inside.

A quick question: What is the .48 material you referred to?

[Adam Kilpatrick]

Cool news on Epiphany!

Did you reinforce any of the buckle points? In any case I guess I can do that pretty easy myself if I want to, to fix that potential problem.

I'm thinking of doing a small % of my quilt with cuben inner and outer. Will be a vertical edge baffle running down each side, about 4 inches wide. I'm thinking I'll make each one as a tube, bonding the seam about 3/4 inch wide. I'll bond on reinforcment strips all the way around the circumference of the tube where I want the straps to go. Then I make the rest of the quilt almost as normal, sewing through the bonded tube edge to the edge of the nylon-so it will be quadruple thick there (folded), 6x thick on the inch wide reinforced bits (times two, plus maybe a tiny patch at each end). That ought to hold! So this edge tube will effectively be sewn-thru (the only sewn thru baffle on the quilt), and I'll fill it a bit less than elsewhere, but it will be tucked under mostly anyway. The cuben will save a smidge of weight, but more useful for me is I don't have to worry so much about that edge moving around the in night touching damp surfaces and getting wet. I've noticed this happen as I thrash around with my current quilt (well I notice the wetness later, not really an issue as its an old BPL180 prototype).

[J-L]

With multiple lightweight fabrics available for down bags now in the 0.67-0.75 oz/sq yd range (10D pertex quantum, Argon 0.67, Phantom 10D), is using cuben in a quilt worthwhile?

[Peter Nash]

I chose Cuben because it was the lightest vapor barrier material available. The .51 Cuben is still the lightest vapor barrier available, I assume. Tim Marshall referred to a .48 material in his post above, but I'm not sure what that is.

[Adam Kilpatrick]

There are a lot of other cuben fibers. I remember the .48 seemed to be used a bit in the backpacking segment a few years ago but then the .51 took off and so the .48 stalled. Just depends what you want to order from cubic tech.

I'm thinking of getting some .69 from them as it seems to be one of the lightest they do that has a .18 mylar on it like what the heavier fabrics do. So better for durable hydrostatic head and (gentle) abrasion. For the right jobs :-)

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