I've been considering making a water bag from heat-sealable ripstop nylon, and I'm interested in the possibility of using a roll top closure. I've done several tests and found that my prototypes invariably leak under pressure. Does anyone have any experience attempting to make a truly air-and-water-tight roll top closure? Has anyone had any success at this?

Pressure from inside usually does leak out. Roll-top closures are meant to withstand external pressure.

Cheers

>Pressure from inside usually does leak out. Roll-top closures are meant to withstand external pressure.

Huh, that's interesting! Learn something new every day!

Roger,

I have heard it suggested that small drybags could be inflated and used as a pillow. Have you heard any accounts of this?

I guess I continue to mull over positive-pressure applications for roll top closures because I can't see why they should necessarily be leaky. The standard buckled canoe closure crumples and creases the material, and I can see how these folds could be leaky. But, as an alternative, I tried rolling the material tightly around a tube, and it still seems to leak under pressure.

If a way could be found to make a truly airtight roll top, a single bag could then serve as a water bag, a drybag/stuffsack, an inflatable pillow, and a pump for an inflatable sleeping pad.

In my experience, those rolltop bag pillows last about 45 seconds before deflating. I began to assume people meant to use them as a pillow by putting extra clothes in them, not by inflating them.

> suggested that small drybags could be inflated and used as a pillow.
My experiences match those of Travis.

Cheers

Here is an article on bags from 2006.

http://jwbasecamp.com/Articles/DryGear/index.html

I sometimes use a down vest inside a roll-top dry bag. Sometimes it stays up all night, sometimes it goes down very quickly. One day I figure out why...

I have not experienced roll top closures staying inflated, but if they sometimes do I wonder if a film of grease,wax or condensation rolled in the neck of a well rolled closure of smooth coated fabric, would make the difference?

I've wondered about this as well. It seems that a bit of rubber (silicone sheet/film?) on the inside of the closure might give a better seal.

Tried it.

I put a thin line of silicone around the opening--it resembled a ziploc bag closure (very rudimentary of course). The silicone didn't like whatever the stuff sack was made of and it peeled off. But, I did get a few attempts in at keeping it inflated. No avail.

Want a great pillow that doubles as a camp seat and frame for a frameless pack? Read my review of the Thermarest Lite Seat.

Sorry, back on topic now.....rolltop closures.

Edited by T.L. on 03/12/2010 14:31:58 MST.