I've had my cuben in a nasty rain storm. I noticed no difference once I wiped it down with my camp towel. A little moist as with anything that's gotten soaked. But once strung up at the other camp site... dried in a matter of 15-20 minutes.
I've had my cuben in a nasty rain storm. I noticed no difference once I wiped it down with my camp towel. A little moist as with anything that's gotten soaked. But once strung up at the other camp site... dried in a matter of 15-20 minutes.
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There was a thread a while back, ( if I can find it, I'll add a link here), discussing the hydrostatic head figure for cuben. Some reports indicate it is quite low & not as waterproof as some tents! If that is the case, some water could be held within the laminate layers, which would seem to be borne out by your experiments/experiences.
I still fancy one though
Very interesting post. Maybe Cuben is not for me. It rains a lot where i live. I've been contemplating a cuben tarp, but after reading this, I think I'll save my money and stick with my Warbonnet Superfly
Joey, I remember you have a ZPack, and the obvious in your details to the left. Anyway, did you seal your tarp on the inside or outside of the sewn ridge line? I sealed the inside of mine, but I was thinking that if its sealed on the inside like mine that the actual thread running the entire length of the ride line may have absorbed some water. The seal on the inside of course kept it from leaking through. Anywhere the thread is exposed to water, it would absorb it. You also have 12 tie out loops plus the little tie out on the outside top made from material that would absorb water.
I recently had my ZPack tarp at the MAHHA Pre-Hike, and it rained pretty much 3 days on it. I didn't pay attention when I packed up, but I didn't notice any additional weight either. I wiped it down before packing it also.
If someone is up to it, cause it seams like to much time and work for me. Being honest here. You could take all the tie out lines off your tarp weigh it dry, then soak it in the tub for awhile. Take it out, shake it off the best you can, then weigh it. Then wipe it down the best you can and weigh it again. Remember, any materials such as thread or tie out loops will absorb some of the water. So we gotta take that into account.
Careful there, trunks. There's nothing I've tried or read about that suggests water is being absorbed by the material, just that it has water on the surface when it gets wet. We don't know that cuben doesn't absorb water; it will take more testing to tell us whether it gets between the layers. We do know (from reading) that nylon (even silicone coated nylon) does absorb water, and that polyester (which is used for the outer layers of ordinary cuben) does not. If anything, my small test suggests that the extra weight is that of water clinging to the surface, but more testing is needed.
I sealed my tarp from the outside, so as not to have any soak through on the seams. My lines are zing it, and they may hold a little water. I was feeling it more in the material, and could tell when I was rolling it up to put it in the skins. It's had me confused as to what I was feeling, but I know it was notably heavier. I don't have a scale of the sorts to test this at home with.
I was more curious if anyone had experienced something like this to help explain what I was dealing with. WV's tests have answered a lot, and it seems a simple wipe down cloth will take care of this issue for me. It'll be about 3 weeks before I can get out again, but I'll still be using my cuben tarp! Even if it does get heavier after rain, it's still lighter than my silnylon tarp.
This was simply something I hadn't expected and am trying to understand cuben fiber a little better is all.
FWIW - I think mylar is the skin for Cuben so I looked up mylar thinking I would find one problem but found a different possible answer:
http://en.wikipedia.org/wiki/BoPET
"If it were produced without any additives, the surface of the film would be so smooth that layers would adhere strongly to one another when the film is wound up, similar to the sticking of clean glass plates when stacked. To make handling possible, microscopic inert inorganic particles are usually embedded in the PET to roughen the surface of the film."
That, in turn, leaves me wondering if the issue is either the pores in the Mylar holding minute drops so that shaking does not impart enough energy to get them off but blotting as in wiping does. Another issue could be the additive absorbs water.
Just some things to explore. ;-)
Sorry David, maybe i should have chosen my words more carefully...
These threads make interesting reading though:
http://www.backpackinglight.com/cgi-...hread_id=44516
and the follow up tests:
http://www.backpackinglight.com/cgi-...26&startat=100
To save you searching i have saved the pdfs as jpg's:
These are the results of testing the hydrostatic head of different weights of Cuben, both new and aged.
The hydrostatic head is measured by the amount of water, in mm, which can be suspended above the fabric before water seeps through a material, 1500mm is considered rainproof.
The results seem to speak for themselves...
Now, perhaps, and i say perhaps, what could be happening is that if water can seep through cuben, which tests show it can. Then surely it is possible that some water could also be held within the pores of the fabric, thus adding the extra weight?
I'm not saying this water is also going between the laminate layers, you're right, that would need further testing. But theoretically, after repeated wetting, packing away & folding...
James
Am I reading this correctly? It looks like sub 1 oz cuben is technically not rainproof?
If you look towards the middle of the bottom graph, there are some more sub 1oz that seem to score better when new, but of the 10 sub 1oz cuben samples tested, only 2 seem to pass the "rainproof" test when aged!
I just want to point out that these tests & results aren't mine - before i get shot down in flames. I've just done the internet searches to find the info
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