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Cuben tent for mountaineering?
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Franco Darioli
(Franco) - M

Locale: @Tarptent
Cuben tent for mountaineering? on 04/06/2014 23:57:54 MDT Print View

Going back to the why not Cuben...
A very popular design for alpine tents is the freestanding two pole wedge type ,like this :
BD Firstlight
(I used that shot before to illustrate why front entry sometimes works better...)
Anyway these kind of tents are small and have by necessity poor air flow so condensation is a problem.
Most makes claim that their fabric "breathes" and up to a point they might, but in the end most drip or have ice /frost build up and maybe Cuben could be more expensive and not better in this regard .

Dave -
(FamilyGuy) - F

Locale: Up there
Re: Cuben tent for mountaineering? on 04/07/2014 00:03:51 MDT Print View

I also can't see how the popular weights of. Cuben currently used for shelters could take the abrasion that would occur at points where the fabric would rub against the poles, at least with the proven wedge design for mountaineering. But I am probably wrong.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Cuben Fiber on 04/07/2014 04:28:48 MDT Print View

Hi Ron (Bell)

First of all, can I reassure you that I will not take offence. I have a hide like a warthog, and just keep smiling.

Second, it's about time some of you guys (Henry, Ron M, Ron B, etc) did contribute a bit more to some of the discussions here! You have a depth of experience most everyone else lacks. We welcome your contributions.

Now, to the issues about Cuban.

First of all, just because Richard's testing was done a few years ago does not mean it is no longer valid. Richard is a professional, using professional testing gear. And 2011 is not THAT long ago!

Yes, Richard is a respected BPL contributor. He has earned that respect by his work on fabrics. No, Richard is not a BPL staffer.

Second, I have to say that your claim that 'There is one early 2011 BPL post by Richard Nisley' is a bit off the mark. There was a thread on fabric testing which went on for a long time. Richard tested a very wide range of fabrics both new and after a moderately standardised amount of 'wear' - done following known fabric testing Standards. Both Richard and I are fairly familiar with professional fabric testing Standards, for professional reasons.

What we found was that both light 'crackly' spinnaker fabric and light Cuban Fibre fabric could eventually develop pin holes at the corners of creases, and these pin holes could leak under pressure. This is not to be wondered at: it is in the nature of the materials involved. Testing the fabrics like this did not destroy the fabrics either. If it could then the fabrics would be useless in the field.

However, I am quite happy to agree that for many users, the pin holes will not matter as the pressure from rain will not be that high. My own opinion is that this latter is why so many Cuban tarp users remain happy with their tarps. Fair enough: carry on tarping!

In addition, there were one or two other threads which covered the problems with stitch holes expanding under load (eg guy ropes). There were even photos of the expanded holes. I think we all understood back at that stage that sewing Cuban Fiber fabric is not the solution.

> flash ahead to 2014 and folks, including Roger, still reference that post like it
> is the absolute truth.
Um, well, the measurements and observations and photos were made by several of us. That is indeed absolute truth. The validity of the test results does not decay with age. That is another scientific truth.

> The primary way to build cuban fiber seams in 2014 is bonding- not by sewing.
I do not think anyone is arguing with you here. Not even me! Bonding is the way to go.

Are we wrong to pay attention to lab testing using acknowledged industry Standards and professional lab testing gear? I think not. Should we ignore the (tens of) thousands of hours of field use? I think not. Both are valid; both have lots of meaning.

Roger Caffin (PhD)
(In my own right, not as a BPL Staffer)

Robert Meurant
(rmeurant) - MLife
@ Ron Bell on 04/07/2014 04:43:19 MDT Print View

With regard to your statement that "That’s a heck of a lot of field use with next to zero online reports of major issues in waterproofness or strength", the problem may be that not all failures are reported.

While I am an enthusiast for cuben, having my brand new cuben pyramid shelter disintegrate under brisk winds and rather hot weather, at the start of a one month camping sojourn in Japan, provided me with direct evidence that failures do occur with cuben, and can be catastrophic.

I emphasize that the manufacturer, although American, was NOT MLD (nor HMG). The tape near the apex started coming off, and in addition, tear marks like a perforated strip near to and parallel to the top of the zipper became evident - possibly where a line had been sewn erroneously, then removed (?). The apex was beginning to disintegrate, and it became necessary to strike the tent and protect my gear, before the failure became complete.

The workmanship in general was pretty shoddy; some seams looked as though they had been sown by a drunkard, in the dark. It made me angry to look at it. The manufacturer, when phoned, tried to assure me that the cuben pyramid should be treated gently, and not be used in too rough a conditions (God forbid!) He refused to refund the purchase price, as the one month's grace period had expired (I'd had heavy monsoon rains and an excessive workload, and so had only been able to test pitch it once or twice prior to starting the trip).

To be fair, he did agree to fix it and return it for free, and I eventually received it with a new door, of slightly different but noticeably yellow color. But in the meantime, I had to purchase a second tent while in Japan, to continue my trip.

This happened 2 or 3 years ago, and I have refrained from making it public, and embarrassing the manufacturer. But it certainly did happen. While I am at it, the bug inner I had ordered with the tent arrived with a hole near the apex that any self-respecting mozzie would have had no problem in flying through, which I had to fix. The tent pole I ordered had been assembled wrongly, so that when folded, it was much longer than it needed to be, which meant I had to remove the elastic, and reassemble it correctly. One end of the pole had been sawn at an angle...
Since then, I have had a much better experience with a Locus Gear cuben Khufu, with excellent workmanship, and with which I am much content; they are currently making me a ripstop 2/3 inner.

I note also that reinforced cuben Khufu and I think Khafra 'mids are being used by alpinists, and in the Himalayas.
I have the highest respect for MLD products and the DuoMid - I regard the LG Khufu and the Duomid as classic designs - but I do think that cuben shelters can cause problems, particularly when there is shoddy workmanship. Just to reiterate, the problems I had were most emphatically NOT with MLD, HMG, or for that matter Locus Gear, all of whom, as far as I am aware, make first rate gear.

Edited by rmeurant on 04/07/2014 05:19:43 MDT.

William Chilton
(WilliamC3) - MLife

Locale: Antakya
Re: @ Ron Bell on 04/07/2014 06:09:27 MDT Print View

Robert, it seems that the problem with your tent wasn't "... major issues in waterproofness or strength" but indeed, as you said, due to shoddy workmanship. The problems with sewing cuben may have exacerbated things, but it seems the workmanship was the real problem.
Personally, I think you should name the manufacturer. Otherwise, you are casting a doubt over a number of good manufacturers, with the exception of MLD, HMG and Locus Gear.

David Chenault
(DaveC) - BPL Staff - F

Locale: Crown of the Continent
cuben controversy on 04/07/2014 15:52:26 MDT Print View

This thread is overdue in at least four or five ways. I appreciate everyones candor.

matt brisbin
(firestarter01) - F

Locale: Bay Area
Who knew .. on 04/23/2014 10:30:05 MDT Print View

Who knew that post would come this far.

Seems like I missed a few updates since the first few posts. Perhaps somethings up with the BPL notification system? In any case, I appreciate all the info even though it appears to have gotten a bit dicy at times :-) I think I'll still carry on and prototype out a cuben fiber mountaineering tent in my spare time.

Sam Farrington
(scfhome) - M

Locale: Chocorua NH, USA
So What Material to Use for the Next Shelter? on 04/24/2014 22:56:57 MDT Print View

"I think I'll still carry on and prototype out a cuben fiber mountaineering tent in my spare time."

Good. At least we are both on the MYOG track, which is the purpose of this forum.

This thread and the long nights spent studying many similar threads remind me a bit of the long threads formerly read on Thru-Hiker about insulation for sleeping gear. Very interesting, but not enough help in making a decision.

What we hear from the small business folk is that the Cuben is superior if the seams are done with their expertise, expertise that is not shared. So that's no help.

What we hear from Roger and Richard is that some of the Cuben fails sooner or later, but maybe not so badly in practice, or if maybe it's a tarp. That's not much help either.

What we know from Richard's tests is that some of the Cuben leaks and some does not, and ditto with the silnylons; but to a lesser extent with the latter, because we know with reasonable certainty the few silnylons that are consistently good, and where we can buy them.

With the above in mind, we face the core MYOG dilemma; that is, the design and construction (done by us) are a BIG hurdle, fraught with lots of BIG risks of failure. If we can successfully cope with all that, how much sense can it make to use materials that we are unsure of, or that we might be sure of if we could find out more about bonding and such, but can't.

It is not only mountaineers that want a tent that will provide the best protection "when things go wrong," as Roger says. For an ordinary old backpacker like me, there are plenty of situations, on the Continental Divide for example, where the best protection is essential. I would love to make the Cuben tent already designed in my noggin; but without the materials, adhesives and techniques I can rely on, it makes no sense. Silnylon exists that I can rely on, that is obtainable, and that works with known techniques. So I'll carry the additional couple of ounces.
(1.1 [oz/sq/yd] minus .75 [oz/sq/yd] = .35 x 6 [sq yds] = 2.1 [ounces]).

Seems like a no-brainer, but maybe I'm missing something.

Edited by scfhome on 04/24/2014 23:14:20 MDT.

Lawson Kline
(Mountainfitter) - M

Cuben and Cold Weather on 05/03/2014 17:07:16 MDT Print View

The reason you don't see more cuben mountaineering tents is because of the construction techniques that would have to be used.. The shelter would have to be both bonded and sewn as bonding alone doesn't work in cold weather. The adhesive looses all its strength and the shelter will just fall apart.

I had a problem with my drybags in cold weather. People were stuffing their down bags in them and then going out in cold weather mountaineering, snow shoeing, skiing, hunting, etc and the seams were failing. The down bag would literately push the seam apart... So I paid 3M to test the problem. Well they found that ALL roll adhesives loose about 50%- 90% of their bond strength under 0F. Put it this way. 9485PC which is the adhesive that Cubic Tech use to recommend before selling their own, and most likely the adhesive most companies are still using has a T-Peel bond strength of 90.4oz/in at room temp and 12.5oz/in at 0F..

So the problem can be fixed by sewing the seams after bonding, BUT then your sewing through a non-woven material which creates a whole set of new problems.....

Greg Mihalik
(greg23) - M

Locale: Colorado
Re: Cuben and Cold Weather on 05/03/2014 17:24:02 MDT Print View

"So I paid 3M to test the problem. Well they found that ALL roll adhesives loose about 50%- 90% of their bond strength under 0F. "

Tip of the hat to you, Lawson. Thanks.

Dave -
(FamilyGuy) - F

Locale: Up there
Re: Re: Cuben and Cold Weather on 05/03/2014 17:37:36 MDT Print View

Looks like someone has figured it out:

Greg Mihalik
(greg23) - M

Locale: Colorado
Re: Re: Re: Cuben and Cold Weather on 05/03/2014 18:21:01 MDT Print View

Well, maybe ...

"Available fall 2013, $2,000;"

... but it doesn't show up on their web site, or a site specific google search.

...wonder if they have seam problems?

Franco Darioli
(Franco) - M

Locale: @Tarptent
Cuben tent for mountaineering? on 05/03/2014 19:41:42 MDT Print View

There is an Amazon link with one listed in stock

Greg Mihalik
(greg23) - M

Locale: Colorado
Re: Cuben tent for mountaineering? on 05/03/2014 20:09:03 MDT Print View

"The only one left in stock". That's interesting.

"...and a Cuben Fiber waterproof breathability canopy material with E-Vent."

So, eVent/Dyneema/eVent, is a little bit different than polyester/Dyneema/polyester.

I believe most eVent seams are sealed with heat bonded polyurethane tape (?)

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Cuben and Cold Weather on 05/04/2014 15:28:14 MDT Print View

Hi Lawson

> 9485PC which is the adhesive that Cubic Tech use to recommend before selling their
> own, and most likely the adhesive most companies are still using has a T-Peel bond
> strength of 90.4oz/in at room temp and 12.5oz/in at 0F.

You get Golden Star Brownie Points for this! Both for actually doing the research, and for posting the results. Thank you!

It does present some very serious problems for seam sealing though - both for Cuben Fibre and for PU-coated. Um ...

Cheers and thanks

Sam Farrington
(scfhome) - M

Locale: Chocorua NH, USA
cuben mountain tent on 05/11/2014 23:21:25 MDT Print View

Assuming "Cubic Tech 1B3" with eVent laminate is about as breathable as the cuben eVent material used in Zpacks' rain jackets, and tested by Richard, there will be a problem. While the material might breathe in a jacket, it will not pass water vapor through a tent canopy sufficiently to prevent condensation on the single wall. Sierra Designs wrote to me sometime ago and acknowledged this was their reason for not making single wall WPB tents. TNF's attempt a few years ago with a knock-off of the TT Scarp, but with a WPB single wall, fizzled for this reason. Poetic justice for TT.

On the more serious issue in this thread, cuben seams, thank you Lawson. More food for thought.