Compression damage to down Sleeping Bags

If the compression sack is the same size and shape as the bottom of the pack other than being longer, it can be of some use when trying to get a bunch of spare clothes along with the sleep gear squeezed down to fit easily. Other wise I like the oversize stuff sack that fits into the corners of the pack. Compressions sacks don’t have to be that much heavier than an oversize stuff sack. Just the weight of a few feet of cord or grosgrain and 3 or four tiny buckles. Maybe not ultralight, but extra light.

Dirt, storing wet, poor laundry techniques  can hurt down insulation. My wife has a bag older than her that is still her warmest bag. It has had the original metal zipper replaced, but is still hanging in there.

I had to mail a big Arctic rated sleeping bag [ 1500 grams of 850FP down: -55C rated for comfort] to Canada a while ago, I could not fit it inside the standard fixed cost box in its normal stuff sack. I bought a cheap vacuum bag and sucked it down on maximum suck until it was as hard as a rock and kept sucking for minutes afterwards until it was like cast iron.
Sent it to Canada and due to Covid it went surface instead of airmail and took 3 months to arrive and then spent another month is customs and quarantine.
Buyer tells me it literally exploded out of the plastic bag when he popped the seal and lofted to its full 300mm in an hour or so.
Compressing down will do very little damage. Consider that the down mills in China ship down in the compressed to the cast iron state as that takes up less room.
Wool is baled for shipment in the same manner and wool presses use tonnes of pressure

I’ve found that my pack is my compression sack. I don’t see how a separate compression sack gets you much of anything, really. I don’t think it makes any difference in terms of how much you can carry.

The only advantage I can think of is that it can compress your sleeping bag to a smaller blob. In general, this is good. The smaller your load, the closer it is to your body, and the less torque you have with your load. However, with a down sleeping bag, I see the difference being minor, and more than made up for by the weight of the sack. You can achieve much the same thing by simply kneeling on the part of your pack that has the sleeping bag, and pulling on the straps. This thread simply confirms what I had assumed, that doing that is fine with a high quality (or even medium quality) down bag, but I would be careful doing that with a synthetic bag over a long period.

To be honest, I don’t know anyone who owns a compression sack, or why they would use one, other than what Edward did, or something similar.

I carry a “just in case” set of gear when day skiing away from camp. It’s usually a Uniqlo UL down parka and an old summer sleeping bag and these are in addition to my warm layer when stopping. Being emergency use only gear I keep them in a very small compression bag that is always in the very bottom of my daypack along with a bivvy sack.
I have considered vacuum packing but I can’t find a small enough and strong enough bag locally that weighs less than the small compression bag I currently have. Do this at the start of the white season and they stay there until the snow melts. I can see this as being a good reason for using a compression bag, it’s a volume control problem rather than a weight issue. I’m a bigger feller and wear XL and XXL clothing and my daypack is only 40 litres, storm clothing and a DAS parka takes up almost all of it, so the emergency gear needs to take up as little room as possible

Edward John,

sounds like you have and efficient and well thought out  “just in case” kit.  I do not carry a sleeping bag. I do carry an extra insulation layer for both top and bottom and a Adventure Medical Kits Thermo-Lite II Single Bivvy and a 48″ CC blue foam pad.  I am normally with at least one other person who is as well or better aware of the essentials necessary if benighted.

Thanks for you thoughts.  Jim

I have a down quilt that I used on the PCT (GoLite Ultra 20) and have washed only once, and I am one of these people who pulls the bag over my head and breathes into it all night long.

I never stuff it, and I keep it hung up in a closet when not in use. Otherwise I think I don’t take a huge amount of care with it. The key is that I take time out each day on my hikes to let it dry in the sun and I do the same when I get home.

Recently it got a hole and the feathers started to come out. The vast majority of the stuff inside is like the consistency of chopped up down, not feathers. I don’t think you could damage this stuff crushing it tight in a compression sack.

I’ve gotten over 12 years of service from my quilt. Except for the small hole which I fixed, it’s in great shape. I would not worry about supposed fragility of down in the least.