Looking for a substitute for a water proof stuff sack?  On a recent trip to the BW with the family last weekend I noticed the wife had packed away some clothes in  (You need to Login or Register to view media files and links) and thought; "hey, that would make a great space saving dry bag for clothing in my pack."  I like stuff sacks but hate that they collapse into a mostly a ball shape - not real conducive to using space in a mostly square shaped pack.  I laid my clothes flat in the bag, zipped it closed it 3/4 of the way and then laid on top of it to press the remaining air out and then zipped it completely shut.  The Large size fit perfectly in my pack and used the space much better than a compression sack.  Many of you are probably way ahead of me on this idea but thought I would share anyway.

Good idea but I think this set-up does it one better.
Same principal, but instead of squeezing the air out and zipping shut which more often than not leaves some air trapped, this item lets you zip-lock end while bag is full.
You lay your clothes in flat, zip shut and roll from sealed end toward the zipper. They have built in one way valves that let air out, keep water/bugs out. Plastic is reinforced with nylon strands for strength.
I separate my clothes into different size bags.
One complete outfit, shirt/pants/ t-shirt/underwear/socks goes in a medium sized bag. They come in various sizes so you can segregate you clothing and avoid having to open and sort thru a big bag.
I lay these flat in pack. You can't believe how much space you save. Compressed there about 1" thick and whatever w x l size you choose.
Another nice feature is you can put your dirty/smelly clothes in, re-seal and they don't smell or contaminate your clean stuff.
In camp I lay them in tent for easy access.
These are by Eagle Creek, but I believe Coughlans and Coleman make similar products.
I got my first set at K-Mart, the next set at Target.
Similar to the Space Bag Vacuum seal bags they sell on TV, but meant for travel. Space Bag sells them too.
If you like the big Zip Lock concept, I think you'll like these as well?
You could put the rolled storage sacks IN a big Zip-Lock and have the best of both worlds.

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I think this solution would work best for squarish packs than those that are round.  I've used this technique several times when packing luggage (a squarish container), but my gear pack is more rounded.  I still use stuff sacks for that pack.  I've found if you don't "stuff" the stuff sack that it will conform nicely into an irregular shape, thus filling what would normally be a void.

As for the square (air bleed) zip locks.  They are heavier than even the heavy duty zip locks and the nylon is a bit slicker.  The downsize for travel is that when placed on a flat surface (like a bed) they tend to slide all over the place rather remaining stacked.  After a while, I was afraid that a bag might slide off the flat surface into a cranny and be left behind.  So, I've mostly ditched using them for luggage-based travel.

dd

Neat!  I love ZipLocks, they waterproof so much of my gear.

Recently switched from a boxy pack (Lowe Contour IV) to a curvy one (Gregory) and it's really a different packing paradigm.  I'm still working out the best way to pack it.  On my square pack I would always find little gaps that could be crammed with sundry items like rope & fuel bottles.  Not so much on the curvy one.