Weatherproof Sleeping Bag

Would a bag with an outer layer of Epic be sufficient for your needs? My Nunatak quilt is has an outer layer of Epic which I have been happy with.

Isn't accumulated moisture a problem for down regardless of the breath ability?

>Isn't accumulated moisture a problem for down regardless of the breath ability?

YES. If it is cold enough OR damp enough, this is a problem for all bags. The best solution (other than a VBL) is to roll the bag up IMMEDIATELY after getting out of it…before the moisture has a chance to cool from vapour phase to liquid phase. A bivy bag or DWR top won't stop your own body moisture from accumulating in the down. If the temps are cold enough for the moisture to condense while you are still in the bag, then there's nothing you can do about it, but when it's that cold you really should be using a VBL.

Here's a link to the 15 degree Marmot Helium EQ bag. I thought that the 30 degree Hydrogen also came in an "EQ" model too. Maybe it was discontinued?

http://marmot.com/fall_2008/equipment/sleeping_bags/ultralight/helium_eq_reg

I can attest to the Helium EQ being waterproof.

I have a detailed review of the bag on the forum.

The short of it is that my tent collapsed and I spent a night curled up in a ball inside the Helium EQ in a half inch of muddy water the whole night.

The exterior of my bag was completely wet, but I was dry and the bag did not lose any loft.

Please note that to achieve this, I spent some 3 or 4 hours painstakingly seam sealing my sleeping bag. It is not "waterproof" out of the bag.

Best way I found to seam seal it would be to take other sleeping bags, comfortorts, etc and load the thing up until it is puffed up and firm.

Then you can more easily seam seal it by yourself….my wife helped me work on mine. (She must love me if she puts up with my hours of anal retentive sealing and fussing over UL gear. Or maybe she wants me to go on more solo trips so that she can collect on my life insurance?).

-Tony

After rolling the bag up Allison, what do you do next? Eventually the bag is going to cool off. Thanks, John

I think the idea is that you push all the air with water vapor out so as the bag then cools there is no damp air which can condense.

Thanks Evan! Am I the only one that hasn't heard this tip before? BTW, would anyone happen to know what would cause condensation inside the tent (single wall) on objects therein but have simultaneously dry tent walls, both inside and out?

Condensation forms on things where there is a largre-ish difference in temp between that object and the (moisutre-laden) air. So something like a cold water bottle or cold fuel canister, or a stuff sack that is full of clothing that is colder then the inside of the tent can form condensation.