[at-l] Re: compression bags

[spiriteagle99@hotmail.com (Jim and/or Ginny Owen)]

kahley wrote:
>At 01:31 PM 9/8/02 -0400, Jim Stewart wrote:
>>Any suggestions? What are ya'll doing for compressing sleeping bags?  I
>>know the down bags will compress more than the synthetic, but - well, I
>>can't put another sleeping bag in the budget...
>
>Try hard to stretch that budget.  Did you read the tag that came
>with your bag any storage instructions?  I bet it said o store it loose to
>avoid compaction.  Down Bags say that too but it's much more of an issue
>with synthetics.  They don't have the resilience that down has so we cinch
>them up tight and squish out what loft they have.

Kahley -
We just got back from Montana last night and I may catch up on all this
stuff by Christmas - but I couldn't pass this one up cause I didn't see
anyone say what needed to be said about it.

Those who use synthetic sleeping bags should NEVER NEVER NEVER EVER use a
compression sack. Reason? --- the first time they stuff that synthetic bag
into a stuff sack (NOT a compression sack) it's been estimated that they'll
lose 10% of the loft (and therefore 10% of the insulation value) of the bag.
  Their nice new 20* bag just became a 25* bag because they've collapsed
some of those nice little hollow fiber filaments (tubes) that provide the
"air-space" that provides the  insulation. And many of those filaments won't
recover from the damage.  That part is elementary material dynamics/thermal
properties stuff.  Those who don't understand that part need to learn about
it - they're welcome to get back to me if they want to discuss it.

Now - add the additional compaction provided by a compression sack and
they're into MAJOR compression of the insulation - with even greater damage
to the filaments and even less recovery  - and their nice new 20* bag just
became a 30* bag.

And that's just the "first" time they compress it.  It'll lose a little
more insulation capacity, a little more loft every time they compress it.
And soon enough their 20* bag will be a 50* bag.  Is that what anyone wants?

So - how about a down bag?  Same general effect except that down recovers
its loft (mostly) while the synthetic fibers don't.

When I started backpacking 50 years ago, I used a down bag.  Then about 12
years ago I got "smart" and decided synthetic was the way to go because of
the development of new insulation materials and because, as someone
mentioned, wet down is useless.  But over the last 10 years I learned
through hard experience that the synthetics gradually lose their loft even
under the best of circumstances.  So I'm back to using down again - in spite
of the high winds, "hypothermia" weather (a cold deluge) and tent collapse
that we had last Friday night at a 9000' campsite.

We still have 0* synthetic bags - and use them when appropriate.  But we
more often use the 20* down bags for both weight and warmth reasons.

If someone's trying to save on pack weight, then get a lighter pack, a
lighter tent, lighter equipment - but don't screw up your sleeping bag in
the process.  That bag will be your best friend for a thruhike - or any long
hike.  A compression sack is only for those who don't care about their best
friend - or have the money to replace the sleeping bag every couple months -
or are ignorant.  Or will NEVER NEVER EVER put (or find) themselves in a
life-threatening situation.

Walk softly,
Jim






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