Cuben fiber gravity filter system?

[Matthew Perry]

Has anyone used a cuben fiber roll top dry bag as a gravity water filter system? Pros/cons?
Silnylon tends to "weep" through, but what about extended use? Does the cuben material develop pin hole leaks due to what is known as mylar shrinkage? In theory, it's not a problem keeping the water out because the pressure isn't that great but when you increase the pressure from the inside, overtime they will leak.
Thoughts?

Thanks!

M

[Matthew Perry]

C'mon….someone has to have done this….?

[Eric Lundquist]

I haven't done this but I'm definitely interested in what others have come up with. Definitely less weight and more compact than my current 2L Platypus.

[Dale South]

I just recently changed the sil roll top bag of my DIY gravity filter to a cuben bag. I usually do not bother filtering my water unless I am on a trip that I must get my water from a lowland stream, pond or river. I have therefore only used it in the field once and it worked fine with no problems.

[Mary D]

Hi, Matt, how are you doing these days?

I've been wondering about this, too. I currently use a Sea-to-Summit Ultra Sil dry bag for my DIY gravity filter. The stiff collar is great for collecting water and the bag can be hung by the closure strap. I haven't had problems with water weeping through. My reservations about using a cuben dry bag center around the possibility of puncture when the bag is hung from a tree branch, especially if it's hanging against stubs of previously broken-off branches. I also await more field reports using a cuben bag!

I'm especially interested because since my dog Hysson contracted a bad case of giardia a couple of months ago (he "exploded" all over the car, necessitating much nose-holding the rest of the way home and several hours of cleanup after we got there), I'm now filtering his drinking water, too. Any weight savings on the cuben would allow me to use a bigger bag!

[Gary Dunckel]

I started to do a little experiment with a cuben bag myself a year or so ago. I filled up a 2 L sized cuben roll top that I bought from Lawson, and hung it up outside all night. The bag definitely weeped, as there was a small puddle on the patio in the morning. Not a lot of water loss, but noticeable. This was a new bag, and I would expect more and more weeping as the bag ages.

[D G]

Mathew,

Bill Fornshell made one as described in this thread:

http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/1294/index.html

[Matthew Perry]

Daniel,
Interesting you should post that thread is my inspiration. I am even using the ULA Amigo filter to start with. I H A T E (!) the standard bag and am looking at swapping it for a cuben roll top dry bag. The thread does not mention how the cuben worked when water was added. I might just bite the bullet and try it out and report back.

M

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