Cuben Fibre compression stuff sacks

[mik matra]

Does anyone make these? I can't find anything?????

Many thanks :)

Mik.

[Derrick White]

They are made by at least these three:

Hyperlight Mountain Gear

Zpacks

Mount Laurel Designs

Mountain Hardwear (These Event bottoms)

[mik matra]

I specifically need 'compression' stuff sack.

My Western Mountaineering bag came with a stuff sack that takes up too much room and I have noticed that I can compress the bag down further……so I am in search for a compression stuff sack.

[Derrick White]

I consider any air tightwater proof stuff sac to be compressible, i.e. roll top varieties.

All of the above fit that description except the Hyperlight Mountain Gear ones.

If you need compression straps to meet the definition of compressible, I know of none that are made of cuben.

Derrick

[Jim Colten]

also not compression sacks but Granite Gear makes cuben/event sacks

[Kate Magill]

For the sake of your down bag, I would reconsider whether or not you actually *need* the compression. Unless you are trying to get away with a very low-volume pack (in which case, consider a lower-volume sleep system?), packing your sleeping bag should not require compression straps. Stuffing your bag into your pack as loosely as possible, rather than as tightly as possible, will extend the life of its loft and hence its warmth.

[mik matra]

"For the sake of your down bag, I would reconsider whether or not you actually *need* the compression"

Yes this is exactly what I am trying to achieve. Though I thought I read that only synth insulation suffers from compression packaging not down. I treat the sleeping bag as I should, only having it compressed when travelling and NEVER at any other time. In camp it's unpacked, at home it's in it's big bag.

[Kate Magill]

Synth is definitely less resilient than down and loses its loft faster. However, all insulations lose loft over time. There's a thread discussing this from about a year and a half back:

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=57909

Seems like there is no hard and fast consensus, but lots of anecdotal advice. My instinct, as someone who regularly spends weeks or months at a time living out of a backpack, is that it's best to be as gentle as possible on the down, even the higher fill power stuff. My experience has been that, over time, down doesn't respond well to repeated compression and decompression. Better than synthetics, sure, but definitely not ideal. The more you crank down on a puffy, the longer it takes to regain its full loft when you unpack it.

I'm also in the camp that it is more space-efficient to let the sleeping bag expand to take up space around other items in the bottom of your pack, essentially maximizing your usable space. With this approach, the sleeping bag (and other soft stuff) is less like a little brick and more like the mortar. I'm sure there are a bunch of threads on here about packing technique, too, if you feel like investigating different methods.

[Marko Botsaris]

Mik., under NO condition EVER put you WM bag in a stuff sack smaller than the one they supply, and even then only while it is in the pack. One thing that is true, and has absolutely be verified is if you ever use what would traditionally be call a "compression" sack you will more or less permanently lose some loft. You may damage one of the most expensive and important gear items in your kit. I think that you are even considering doing this mean there is something else wrong somewhere. You should basically plan your packing style, and pack size, and so on entirely around not ever having to force you bag into a very highly compressed state, and compressing it smaller than the provided sack qualifies for that. WM warn against this as well. Not for nothing, I hope you are also storing it fully expanded.

I'm definitely in the no compression camp. None of my bags has ever been "compressed". Personally, I would never even use the provided stuff sack. I put my bag on the bottom of my pack (no stuff sack at all), and it gets compressed exactly how much it needs to be to close the pack, and no more. At home it spends all of its time fully expanded in a cotton sack. If you don't over-compress the bag you are supposed to be able to get most of the loft back that you loose over time if you properly wash the bag. I have down bags that are 15 years old I use, but I know some people here have reported properly cared for bags that are still fine after 30 years.

I use a pack liner but virtually no stuff sacks. I will just throw my down jacket and any extra clothes I will not need during the day inside the bag. All my "dinky" stuff goes in small ziplocks and the stuffed in the "corners". This is both the most efficient and fastest way to pack things. I'm not into the obsessive (possibly color coded) separate stuff sack method – leaving aside they have no *actual* function and weigh more they make efficient packing impossible, and even can create more stress on your pack.

Unfortunately, I was never able to convince my mother that this was the most efficient way to organize my room when I was a kid :-)

[Anonymous]

+1 on what Mark said

I throw my sleeping bag, cloths I want to keep dry, & anything else i want to keep dry in a gossamergear pack liner(trash co all my cloths into a gossamergear pack liner. I always loosely compress my bag, then allow the weight of all my gear to compress it a little more. My food is in a drybag & everything else is in ziplock bags. It's pretty easy for me to keep up with everything & pack/unpack at night/morning.

Down suffers from being over compressed as well. If memory serves me I think that around a 1 to 6 ratio of compression to normal full loft is about where you want to be at. I really don't think you'd want a compression bag for your down sleeping bag. It'd make the shape of your sleeping bag into a ball, which isn't very easy to pack in the bottom of your pack. I'd guess the compressed sleeping bag would leave unfilled space at the bottom of the bag & could even push against your frame causing discomfort.

Sidenote:
I read your thread on your gear getting wet when it rained. I've fallen in 3foot deep water & got my pack completely drenched. My gear in my pack liner was bone dry when I checked it out at camp.

[Matt Dirksen]

"One thing that is true, and has absolutely be verified is if you ever use what would traditionally be call a "compression" sack you will more or less permanently lose some loft. You may damage one of the most expensive and important gear items in your kit. "

Mark, has this been been scientifically proven? I think I did read at some point that a scientific study was done 10-15 years ago, but concluded that it would take an extreme amount of repetive force to actually perminantly damage the down (much more force than daily compression sack usage could ever exhert on the down.) I don't know of any recent studies, but it seems to me, perminant damage to down products through short term over compression is anecdotal at best.

I do understand that any manufacturer is not going to reccommend using a stuff sack smaller than what is provided, but does WM actually void their warranty if someone uses a compression sack?

Regardless, I totally agree with your recommendation of not even considering using a stuff sack if one doesn't need to. Most backpacs compress, so why carry a redundancy of compression straps?

Admittedly, I've used compression stuff sacks on an as-needed basis for an old North Face down bag for almost 30 years now. The great thing about down is its long term durability. I have sent the bag back to NF twice over its life for professional cleaning by them. As a courtisy, they have re-lofted the bag to its original specs. I think I paid $25 each time.

Perhaps WM will do this too.

Matt

[Max Dilthey]

Ah, the old BPL Evade-and-Distract.

[James Marco]

I actually did a survey of about 100 sleeping bags 7-8 years ago. None of the down bags were damaged by anything up to a 10:1 compression. This is the normal compression for any bags used by hikers. Extreme compression, ie 20:1, noted some loss of loft after about a month of daily use, as a through hiker would do, but it was unclear whether this was caused by compression or dirt and accumulated oils in the down. I personnaly compress my bag about 15:1 in an eVent Dry/compression bag.

Anyway, I use a very small pack, the GG Murmur. If I just stuffed my bag in it, it will fill the body. I NEED to compress it in a compression bag. My other packs are a bit larger, but the same sizing problems hold. In 10 years, with my new bag, it has ALWAYS been compressed between 10:1 and 15:1 when hiking. It still lofts to more than its new amount after a washing. There has been no detectable damage done, which follows the results of my study.

Also, washing a bag, correctly, does not harm down. About 1/4-1/3 the amount of down wash in a clean (no detergents!) agitatorless washer. Rinse three times with water. Dry on as high as the shell material will tolerate. My jacket and all my bags get this at least once per year. In regular use, my 3 season bag gets it every 2 weeks or so. (Body oils/dirt will cause the down to stick together, laying on it could tear the down fibers loose.)

The normal life expectancy is about 20 to 30 years, depending on usage, for a good down bag. I assume my 3 season bag is about half way through it's lifetime.

[Bob Gross]

"The normal life expectancy is about 20 to 30 years, depending on usage, for a good down bag."

My oldest down bag is 35 years old, and it is still going strong (or is that the odor that is strong?). I intend to keep using it until it is on Medicare. It is always stored loosely and is always carried compressed.

–B.G.–

[James Marco]

Good piece of data, BG. Thanks!

Well, maybe I should have written at least 20-30 years, heh?

[Marko Botsaris]

OK, interesting. I hope I was wrong. I seem to remember a specific article on here, maybe as many as 10 years ago that had specific numbers for the permanent loss of lost when "over-compressed" with numbers like 20-30% reduction in loft after a *single* over compression. Possibly I'm remembering the results for synthetics, which ironically one actually tends to need to compress more, and got them mixed up in my mind. That's why I have you guys, to over come my memory loss. :-).

I'd be supper happy if you couldn't permanently harm it – one less thing to worry about.

[Jerry Adams]

I'm more interested in the thread drift subject, sorry Max : )

I have a synthetic quilt I've compressed maybe 10:1 for maybe 20 nights and it seems like the loft and warmth have decreased 30%, but I don't have carefully measured data.

I appreciate the 10:1 or 15:1 compression ratios allowable for down, even though they're not real carefully measured. I just made a down quilt so I'll stay within that.

[M B]

When I need the room, which isnt too often, I can stuff my 40F quilt into a zpacks medium roll top, and squeeze it down to the size of a cantaloupe by hand. I can actually fit all my clothing in there with it, across the bottom of my pack.

I put my megalite into the same size cuben sack too if I need space. It is stuffed a little tighter than the WM sack, but the cuben is more water resistant, and lighter.

Unless Im carrying 2 wks food though, or a lot of winter gear, I dont need that much space. Just do the cloud thing in the pack liner.

[James Marco]

:…I seem to remember a specific article on here, maybe as many as 10 years ago that had specific numbers for the permanent loss of lost when "over-compressed" with numbers like 20-30% reduction in loft after a *single* over compression. Possibly I'm remembering the results for synthetics,…"

I do not doubt that. I remember flipping through and reviewing an article like that. I do not remember the date on it though. Anyway, it struck me that they did not shake the bag thuroughly and wait 30 minutes or so for it to regain it's loft. In a later article (I believe it was Ryan's) the author went on to discuss loss of loft due to moisture take-up by down, ie, dampness. But again, the shaking and mechanical lofting was not done to any effective degree.

Yes, I agree. Synthetics, such as holofill and varients, will kink permanently when compressed around 5 to 1. Finer fibers are better, more flexible fibers are better, as are some additives to the plastics to cause them to have a memory of the origonal extruded shape. But they only last 3-5 years, unless you are a zeolot about keeping them uncompressed. The synthetic fibers are mostly based on holofill.

If damp, a bag may take up to 2 minutes of shaking to seperate compressed down. Often in the summer, I have gone to bed with it damp and woken up with it dry and fully lofted again, by morning. If it is fairly dry, about 30secs or less will do OK. Use your own judgement.

In any case, a down plume, once compressed, can be as small as one or two percent of the origonal fully opened plume in area. Theoretically, you should be able to acheive about 50:1, but down will resist you more and more as you compress it further and further. About 10-20 pounds on each strap will compress my bag and jacket enough to fit into the small pack. This is around 15:1. Damp it may go much easier, but I go more by size than compression ratios.

Compressing will squeeze air out, often overlapping these fibers into a compressed sheet. They will tend to stay that way due to the micro-fibers gripping each other. Shaking will mechanicaly move these out to the more natural plume condition. Basicaly, it increases loft considerably. I would guess a good 100-400% over an unshaken bag depending on humidity and dampness. Heat, just your body heat, will tend to "straighten" these fibers, too. Hence, the increasing loft over the course of the night.

If you hike 10 hours a day, a relativly high milage day of around 20mi at 2mph, this means that 12-14 hours are left for the bag to regain its loft before being compressed again. Down WILL regain as much loft as it can, given the conditions, over about 30 hours. But, 14 hours is only like 1 geometric progression away from the first three, starting at about two hours. Once shaken out and laid open (assumed to be in a dry area like under your tarp) it will continue to regain loft for about 30 hours. But, I normally use mine before that happens. Continual use, as in a through hike, introduces dirt and body oils which I never figured but alow for with my jacket. This has another 4oz of down in it and will protect my core.

One good way to minimize body oils is to use a light set (minimally) of long johns. I usually rinse these on a good hot day in a stream somewhere and put them hanging on my back pouch to dry as I hike. Nope, never lost them in over ten years of doing this. Sometimes I put them on and go swimming. Or, wear them into a shower.

There are lots of tricks you can play with down. Mostly, keep it as dry as you can, and, as clean as you can. Shake the hell out of it after compressing it. It really doesn't hurt it.

Note: That was for good down. Less expensive 550-650 fill down has a large percentage of downy feathers. Compression of these is like compressing holofill.

[Marko Botsaris]

Wow, excellent reply James! Are you SURE you would rather hear a list of compression sacks now Max? :-P

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