Pertex endurance lining for sleeping bag?

[RossageRoll]

Hey folks,

Looking to get myself a new bag from one planet. I was wondering if anyone has experience/opinions on whether i should get the bush-lite -7 with the Pertex outer shell or just stick witht the bungle -7 and the 15D outer.

Having a bit of trouble finding out whether i should shell out the extra 160 for something that might not be that necessary.

Im a pretty warm sleeper who spends most of my bushwalking time out in the south west of tassie

Thanks!

Ross

[Scottyk]

I wouldn't bother personally
In a damp environment like the southwest your sleeping bag is going to get damp over a few days, the pertex won't make much difference as most of the moisture is coming from you whilst your sleeping.
It's just a bit fashionable to have semi waterproof layers on a modern sleeping bag.
Moisture in, on, and all around is a fact of life in this part of the world. Get a synthetic bag and you don't have to worry so much.

[newhue]

Scotty may have a good point. We have had OP bush-lite pertex outer sleep bags for 11 years now. Refilled once, washed once, and done a great job. The moisture on the outside after a cold bivy, or days in a tent sleeping out bad weather in the Tassie is hard to say if it does exactly what it's meant to do. But the bags never felt wet internally of colder because of it. Of course the next opportunity to dry them out in sunlight always prevails. Still we upgraded to new bush-lite -7 pertex bags without hesitation the other day. I know it's all money, and possibly marketing, but just feel when out its going south in some cold forsaken wind swept hell hole bucketing rain, $160 is not much in the scheme of things. Wasted more than that in the blink of an eye on the kids at Xmas.

[nq111]

I wouldn't bother personally
In a damp environment like the southwest your sleeping bag is going to get damp over a few days, the pertex won't make much difference as most of the moisture is coming from you whilst your sleeping.
It's just a bit fashionable to have semi waterproof layers on a modern sleeping bag.
Moisture in, on, and all around is a fact of life in this part of the world. Get a synthetic bag and you don't have to worry so much.

+ 1

I've had both a waterproof (epic) bag and normal bag - and both used a bit in Tassie (The waterproof one extensively).

Even the most breathable waterproof shells reduce vapour loss and most of the moisture is from you, not the outside. A normal shell dries out faster, is cheaper and is lighter.

Just keep up the DWR treatment on a normal shell and you get the best of both worlds. If moisture is a problem manage the moisture coming out of you amazing how much difference a vapour barrier makes.

[simonm]

If moisture is a problem manage the moisture coming out of you amazing how much difference a vapour barrier makes.

Hey nq111 - can you explain in a bit more detail how you do this?

Thanks

[Moondog55]

I can help with that too
It stops insensible perspiration from evaporating from your skin as once the skin is at its preferred moisture level insensible perspiration stops.
So using a VB makes the assumption that you will be sleeping with just a thin non-absorbent layer on such as a thin set of long underwear. However I have used both a VB and a partial VB with synthetic clothing on and noticed that in the morning I dry off very quickly anyway.
My experiments with the partial VB were the winter before last when I used my Tyvek SB cover as a liner one time and found it gave me a few degrees of extra warmth so I continued using it. If using a half bag and duvet inside a large bag I'd be using a half bag VB plus a VB shirt
If you want to experiment use a big rubbish bag as the VB
I've had the same VB for over 30 years and it needs replacing with something lighter, but it still works

[simonm]

Thanks MD - I will look into it some more.

[RossageRoll]

Thanks for all the great tips, i reckon i'll stick with the no lining...i can always just get a barrier of some kind as you guys have all mentioned if i run into issues with moisture

Thanks again!

[nq111]

If moisture is a problem manage the moisture coming out of you amazing how much difference a vapour barrier makes.

Hey nq111 - can you explain in a bit more detail how you do this?

Thanks

Pretty simple really. Add one of these http://www.westernmountaineering.com/sleep-accessories/hotsac-vbl/. A cheaper option is: http://www.adventuremedicalkits.com/survival/shelter/survive-outdoors-longer-emergency-bivvy.html - used one of these when trialling the concept.

Not a bad discussion of the principles (more for active use in colder conditions): http://andrewskurka.com/2011/vapor-barrier-liners-theory-application/

I am well adapted to sleeping in warm, sticky conditions so I tolerate a VBL very well - to well above freezing. Many people only find it comfortable a fair bit below freezing. Either way it is a great lesson when you try it how much moisture you are producing each night and how much that is degrading your down sleeping bag.

I advocate carrying something like a SOL emergency bivvy for all trips where there is a danger of colder than planned for conditions. Lightest warmth for weight boost to a sleeping system even if just for a surprisingly cold night and is a multiuse item for worse emergencies as well.

[simonm]

Thanks nq111 - I might sew a VB barrier out of lightweight sil fabric and test it out when the conditions are right.