Pushing the Cuben Envelope - valve needed
I made a Ziploc Cuben drybag. Several projects are coming together, and this relates to all of them. I wanted a small dry-bag to use in my MollyMac Front Pack, but I wanted something different from a roll-top closure, so I cut the top off a ZipLoc freezer bag and fastened CT.6K.08 to it to form the bag.
The first test was the overnight book test (inflate, seal, put a book on top and leave overnight). It failed; the air escaped by morning.
The second test was the immersion in the sink test (like checking for punctures with a bicycle tire; look for the bubbles to locate the leak). Leak located at the most likely spot - where the Ziploc portion was joined to the cuben at the top corners. I reinforced the weak spots (both corners) with DIY cuben tape. For the initial construction and the repairs the bonding method was 3M Adhesive Transfer Tape 9460 with Primer 94.
Repeated immersion test; no bubbles. Now repeating the overnight book test. See attached photos.
In addition to the wish for a small dry bag with a ziploc closure I also wanted to start work on making air-proof Cuben containers for insulated hammocks and down air mattresses. I'm not sure if a ziploc closure system is tough enough to withstand the pressure on an air mattress. Does anyone know a source for a small one-way valve that I can incorporate? I'm willing to do surgery on water wings if necessary.