Can highly compressing down bag damage it?

[David M]

Thanks for ther tips over in the thread I started about packing. My Exped Lite 700 bag is rather large in the supplied stuff sack. If I used a compression bag to make it smaller or the Exped sack which you expel air out of to compress it (mentioned in the thread) can the down be damaged and reduce the warmth of the bag? Obviously it would not be stored permanently like that but is it OK for walks? (When I store the bag at home I store it in the supplied very large storage bag which ensures that there is no undue compression of the down.)

[Strider]

YES!

It is obviously fine to compress it so some extent but over compression can permanently damage the down, affecting its ability to loft.

Do Exped specify a recommended compressed volume for your bag?

[ryantmalone]

You can compress a down bag a fair amount without it being damaged whilst in your pack for no more than a day or so, however as Strider mentioned, compressing it too much can definitely damage its ability to loft. Storing it in the supplied duffle when youre not hiking is definitely a good idea.

I'd contact Exped, and ask for their advice on it. Depending on the down used, you may be able to compress it a bit more than it is already, however they will know best, and should be able to advise the smallest compression sack possible without damaging your lofting ability.

The bag that I use (a Marmot Helium) is an 850+ loft, and I can compress that down a HUGE amount without damaging its lofting ability using the stuff sack supplied with the bag, and that hasn't degraded a bit since I started using it. Like you, I also store it in the supplied duffle, and it returns to full loft very quickly.

[Giddy_up]

Here are the specs on your bag. The bottom line in the spec sheet shows the packed dimensions, so find a compression sack that fits between those measurements.

http://www.exped.com/exped/web/exped_ho ... endocument


"Experience is a hard teacher because she gives the test first, the lesson afterwards"

[Ent]

Contrary to a few opinions, it is not the down that you will need to worry about. In fact down is mechanically compressed for transportation to a much higher level than any human can achieve. It is the baffles in the bag that can suffer through over compression.

Like anything you need to understand why a manufacturer chose a packing bag. Is it ease of packing or cheap approach to the bag.

Brands like One Planet sell their bags with a compression bag so it they are easy to pack but then can be compressed down. Sea-to-summit make excellent waterproof compression bags and I use them as Western Mountaineering come with a cheap bag. I find I can compress my bags a lot using a S2S bag but do this being prepared to take the risk. One Planet did mention to me that the only problem that they have struck is when one customer crammed two bags into the one compression bag and then compressed it. Apparently, nobody at their factory could achieve this so they replaced the bags and told the owner of them not to repeat his trick as this had torn the interior baffles.

Cheers

[Franco]

Often the devil is in the detail.
Those mechanically compressed bags are perfectly clean.
You will not have the same result once sweat/oils/saliva and so on affects the bag.
My suggestion is to try to always have the bag as clean as possible, it will be warmer and last longer that way.

[GPSGuided]

Surely this compression related damage on down is a continuum. As such, there's no single point of compression (within human strength) that'll differentiate damage vs no damage. So it's just common sense to minimise the time under compression. Compress hard, then just for the day and not leave it in that state for longer than needed.

[wayno]

Surely this compression related damage on down is a continuum. As such, there's no single point of compression (within human strength) that'll differentiate damage vs no damage. So it's just common sense to minimise the time under compression. Compress hard, then just for the day and not leave it in that state for longer than needed.

thats what i'd expect and as franco says depends how dirty and worn the down is over time,,, use your common sense and try not to go mad when compressing it and leave it stored uncompressed if you can, air it properly after use. clean when you need to, use a sleeping bag liner if you're not sleeping in clothes with long legs and sleeves to stop body dirt and oils getting into the bag..

[Joomy]

Often the devil is in the detail.
Those mechanically compressed bags are perfectly clean.
You will not have the same result once sweat/oils/saliva and so on affects the bag.
My suggestion is to try to always have the bag as clean as possible, it will be warmer and last longer that way.

I'm not sure that sweat, oils, etc. will have much affect on the compression resilience of down. I can't be sure but I can't think why that would make a noticeable difference.

All anecdotal evidence suggests that highly compressing down for a short periods at a time (i.e. for less than 24 hrs) doesn't do any lasting damage. Mountaineers have been stuffing very lofty bags into very, very small compression sacks for a long time without trouble.

As far as baffle damage goes, that's why we stuff down bags rather than roll them, which obviously should be done as gently as possible. I've never seen or experienced a blown baffle.

[wayno]

when your down has body oils in it it's less likely to fluff up after compression and its more prone to clumping.. dont under estimate how much oil comes off your body over time....

[Joomy]

when your down has body oils in it it's less likely to fluff up after compression and its more prone to clumping.. dont under estimate how much oil comes off your body over time....

Of course, but why would that affect the resilience of the down?

[Franco]

Joomy,
I am VERY good at stuffing, in fact I have annoyed many over the years pointing out that if they can't put their tent/sleeping bag/mat back into the original container it is because they are not doing it right.
(the fact that I can do it , proves the point...)

It just happens that by accident I had one Macpac sleeping bag stuffed into its very small stuff sack for two years.
His identical mate was left open into a very large mesh bag.
After releasing the compressed bag it puffed up (prompted by some vigorous, maniacal shaking...) to the same size as the other one.

Both bags had been carefully washed, by me, beforehand and had not been used in that 2 year period...
Keep in mind that clean ad dirty are terms not all that often well understood.
Some still think that they are clean when they have a weekly bath and change their sheets once a month....

[wayno]

when your down has body oils in it it's less likely to fluff up after compression and its more prone to clumping.. dont under estimate how much oil comes off your body over time....

Of course, but why would that affect the resilience of the down?

the filaments in the down are more likely to stick together rather than releasing from each other to fluff out fully

[Joomy]

Joomy,
I am VERY good at stuffing, in fact I have annoyed many over the years pointing out that if they can't put their tent/sleeping bag/mat back into the original container it is because they are not doing it right.
(the fact that I can do it , proves the point...)

It just happens that by accident I had one Macpac sleeping bag stuffed into its very small stuff sack for two years.
His identical mate was left open into a very large mesh bag.
After releasing the compressed bag it puffed up (prompted by some vigorous, maniacal shaking...) to the same size as the other one.

Hi Franco,

Sorry if I sounded didactic, I wasn't trying to be. Just trying to answer the original poster's questions. As your experience seems to suggest, there is really not much long-term downside to keeping sleeping bags compressed.

when your down has body oils in it it's less likely to fluff up after compression and its more prone to clumping.. dont under estimate how much oil comes off your body over time....

Of course, but why would that affect the resilience of the down?

the filaments in the down are more likely to stick together rather than releasing from each other to fluff out fully

An ineresting conjecture, wayno, but I've never seen any evidence to support it. I have seen a lot of old, dirty, compressed sleeping bags get almost their full loft back after being washed.

[wayno]

i never said it couldnt be restored after washing i was refering to how the compression affects it when dirty, dont read into things too much

[Franco]

The down in those Macpac is 550 (I think...) .
Some suggested that the higher loft type is more fragile so that may make some difference .

[Joomy]

i never said it couldnt be restored after washing i was refering to how the compression affects it when dirty, dont read into things too much

And my response to your theory was that I've seen dirty bags that have been stored compressed regain their loft after a wash, therefore I don't believe that "dirtiness" i.e. oils from body has much of an effect on the resilience of down.

[wayno]

i wasnt talking about "after washing" at all

[Joomy]

i wasnt talking about "after washing" at all

I know. But your theory is that long-term compression of dirty down permanently affects its ability to restore its loft. Dirty bags lose loft regardless of whether they have been compressed or not, so the way to know whether a bag's loss of loft is due to dirtiness or actual damage to the down is to wash the dirty bag and see if it regains its loft (after being compressed while dirty). If it doesn't then we can say that likely the down has been permanently damaged, and if it does (as I have experienced) then we can say that being compressed while dirty (or dirty while compressed) hasn't affected the down permanently.

Right?

[wayno]

i never said "permanent" you never asked about "permanent" i responded to what you wrote

[Joomy]

i never said "permanent" you never asked about "permanent" i responded to what you wrote

Hmm OK fair enough. I guess just assumed that you were talking about permanent loss of loft through compression since that's what original poster is clearly worried about.

[Ent]

Picking up on the cleanest point. One Planet to me indicated that it has had a few complaints of its bag losing warmth and when they get them back they weight them. Heavy bags are washed and bingo the warmth returns. Like Goretex gear people simply do not wash their gear enough.

I after a seven day trip will wash my bag. So far it has worked a treat.

[iGBH]

So in conclusion, no one (at least as far as contributing to this thread) actually knows.

To add to the anecdotes, i remember a podcast from one of the guys from exped talking about leaving their downmats compressed for an extended period of time. If i remember correctly, he basically said that even after extended storage in a compressed state, the down and its insulating properties returned to original condition after being uncompressed.

[Mark F]

As Ent said, down is stored and transported in extremely compressed bales where it may remain compressed for several months before being used without damage. Compression, as normally applied, has no long lasting effect on down but it may take some time and plenty of shaking etc (see Franco's post) to regain its full performance. Short term compression minimises the time and shaking needed to restore the loft. The quality of the processing also plays a part. Poorly processed down or down with a high quill content can be mechanically damaged by compression.

Contamination by dirt and oils is a totally separate issue and will affect the loft until the bag is cleaned, and may permanently affect the loft. Keep you bag clean by using an inner bag and wash as required.

[wayno]

make sure you air your bag thoroughly after use to remove excess moisture if you're going to store it compressed long term to avoid mould or bacteria buildup....

[David M]

Here is the reply I got from Exped about compressing their bag:

for sure you can buy whatever compression bag and store your sleepingbag there during your trip. Down is amazing - they always come back to the original loft for many, many years.

[GPSGuided]

That settles it!