Looking for a slightly wider sleeping bag

[dvbl]

spider solo, I feel as though I owe you a "research fee" .

Thanks for the helpful info.

 

[Lawn Sale]

How does the sleeping bag breathe? Seems like it wouldn't at all and would make sleeping uncomfortable.

 

[spider solo]

Ahh.. that's what you pay the big bucks for. The various companies have their own "propriety fabrics" that breathe. Much like any of the fancy jackets and outerwear that's on the market today.

It gets so confusing keeping all the available fabrics from getting everyone totally confused that North Face came out with a nice flash card thing so people would have some idea of what they were talking about...it listed about 13 fabrics. Explaining things like Prima Loft for example. (there is more than one kind)

Sleeping bags...there is always a trade off between breatheability and waterproofness.
A waterproof bag gets some of it's warmth rating based on the fact it breathes less and therefore keeps you warmer at a lighter weight than a more highly breather fabric that would soak up water like a sponge...and of course all the variations in between.
Early gortex bags did poorly when they 1st came out..but here we are years later and other fabrics have been invented with better results each company advertising it's own merits of the fabric (and method) they use.
The bags I opted for have"welded seams as opposed to stitched seams which would leak at each baffle.
Still the zipper would be the "Achilles Heel" of most bags.


Safe to say
in either a synth bag or a waterproof bag once you personally get wet your going to have a rough night. A lot depends on keeping yourself dry or keeping dry clothes handy.

 

[DougPaul]

How does the sleeping bag breathe? Seems like it wouldn't at all and would make sleeping uncomfortable.

Primarily by diffusion plus some pumping caused by your breathing.

Down is a big sponge--it can absorb a tremendous amuont of water. (Anyone who has washed a down bag has seen this first hand.) My older (~30 yr old) bags use nylon taffeta or ripstop as a shell fabric, which is no barrier to liquid water. My newer bags (<5yr old) use coated fabrics (eg Pertex) which tend to make water bead up rather than soak into the shell and down. Water vapor can still diffuse through the small pores in the fabric. (A bit like some soft shell fabrics.)

Note that the water vapor from your body can still condense (and perhaps freeze) in the down, even with the modern shell fabrics. The moisture still has to pass through the entire structure of the bag to be eliminated.

The reason that Goretex does not work well in sleeping bags is that it requires a significant temperature difference across the thickness of the fabri to move the moisture.. (The moisture is driven from the warm side to the cold side.) The temp difference is generally adequate in body clothing, but not in sleeping bag shells, tents, packs, etc.

Doug

 

[DougPaul]

Water goes right through down almost instantly so it is the outer fabric that will determine how wet or dry the bag is.
I opted for water proof down bags.

Actually down is a sponge--it can soak up large quantities of water.

So, for example, I slept out in the rain last night the bag stayed dry but...I had zipped an expander section into the bag and that is where it leaked.
I got wet ...the down stayed dry.

There is a good chance that the down absorbed water that got through the shell.

though
on that experiment I'm not sure the fabric on the inside of the bag is as water proof as the outside of the bag...probably not so the emphasis would be not to let the water get inside the bag in the 1st place....

Any waterproofness of a down bag is from the shell fabrics acting as barriers. Water is still likely to leak through seams. Any such water resistant fabric faces the usual tradeoff of waterproofness vs breathability. (Don't forget that moisture from your body has to be able to diffuse out through the bag.) And of course, the manufacturer is free to use different fabrics for the internal and external shells.

I took a cup of water and poured it inside the bag...it puddled up nicely and I just wiped it up.

I hope you air dried your bags after these experiments. Wet down damages easily and can also mildew.

Doug

 

[spider solo]

not too worry. other than a little phraseology here and there I think we are basically on the same page.