Originally Posted by
Dr Jabadski
FWIW, using a (thick) plastic bag serves the added purpose of keeping everything dry. Many of us did a variation when we mobilized to Afghanistan, placed thick heavy lawn/garbage bags INSIDE of our 3-4 required duffle bags. Worked quite well even when the bags were left outside uncovered in the rain for hours at a time.
I’m not a back-packer, don’t some people use plastic bags to keep their packs dry when they're caught outside in the rain, similar to a poncho placed over a backpack? 1 or 2 shouldn’t be significant extra weight and can be folded/rolled into a small volume.
Yup, this is standard advice for backpacking. You pack so that even if your pack gets wet your stuff stays dry.
Garbage bags are a common solution, although personally I use dry sacks instead. A bit more weight but they're much better protection--a dry sack properly closed can withstand a short dunking. You can't do that with trash bags because an airtight seal will have problems with altitude changes. You can roll the top of a trash bag like a dry sack does but don't expect that to survive for too many uses.
It's not going to do anything for protecting your pack from a strap snag, though--and normal packs are full of snaggable points. Long, long ago we checked packs by securing everything the best we could, but that was back when the handling was a lot more manual--I'd be much more worried about it now. I have never tried it but you can buy rolls of the saran-wrap like stuff. What they use in the airports is too wide to be practical to take with you but I have a roll of 6" material that wouldn't be too much of an issue to put in a carry-on and I think would make it past the TSA. Separating the roll and handle would make it look less clubbish.