Cuben / PrimaLoft One – Sleeping Bag

Very nice again, Bill. I love VB's in sub freezing weather. I am actually able to take my 1 layer XP quilt down to the high 20's with the use of a VB liner, the clothes I use to stay warm in those conditions and some golden grain. I never seriously considered VB's as permanent linings and/or shells for cold weather bags. I would love to see how the dual VB on the synthetic and down bags/quilts work. Especially concerning packing, unpacking and loft gain, if significant water can get in though the seams somehow, and if it is able to dry at all if that does happen. Eliminating the bivy will save you lots of weight and complexities too. I can't wait to see pics of your other stuff you've been working on.

Hi David,

My Cuben/ Pertex Quantum Bivy only weighs 3 ounces, but 3 ounces is 3 ounces.

I have used VB's in my sleeping bags at low temperatures for a lot of years. Also in my boots and as mitt liners. The key is being able to control your sweat through venting and what you wear. It takes effort to make it work.

I am about to add the first of my comments about my new RBH Designs – Vapr NTS Shirt and Pants to my Winter AT Hike Thread.

I believe the VB idea can be used to a much higher temperature than most have thought in the past. It may not be for everyone but will be for those that are really in-tune with what their body is doing.

Intresting system for sure. Since you are wearing all VB clothes are you using the cuben as liner material to only save weight then? It does not exactally sound comftorable (lots of crinkly plastic to sleep in…)
Cool idea!

Vapor barriers are sadly very under-rated and highly misunderstood. Nice to someone as yourself (who is very respected around here for your skill, creativity, and ingenuity at making gear) begin incorporating vapor barriers. It's such a simple way to add warmth while reducing weight, but such a difficult concept for most to learn/understand/accept and then use correctly.

Oh no David …. you're not getting away that easy …

Details please …. what clothes are you wearing in the VP liner, what type of VP liner are you using .. what is "Golden Grains", beer or liquor? Do you sleep hot or cold? Able to take it into the high 20's, is that comfortably or just able to sleep for 3 hours at a time?

A normal 1 layer XP quilt should only be good down to about 60, mid 50's with heavy clothes. … getting better than 30 degrees out of a VB liner is pretty significant and could change the direction of several projects I've been considering.

Cutting edge once again Bill ….. good work.

"Oh no David …. you're not getting away that easy …"

It surprised me too. When it gets below 40* when at camp, I carry a montbell thermawrap parka, thermasilk PJ's, 200 weight fleece pants, and polarguard 3D socks. My ex girlriends say I am like a furnace when I sleep, and my results with sleep gear seem to say the same thing. I made a VB liner from reflective silnylon, according to the gathered rantings on a previous VB discussion, the reflective aspect of it would only do any good in situations with inadequate insulation- 28* with 1 layer of XP. I sleep for 6-7 hours with the help of a few shots of goldengrain- grain alcohol, which thins the blood and gets it to hands, feet and face. It takes from your core temp, but thats only dangerous when it's 'survival' type cold. I wake up a bit chilled, but not to the point of severe discomfort. Always eat and drink plenty before bed, and stay out of the wind. The montbell thermawrap parka is the key item though. Its like a whole nother layer of insulation with a hood that stays put.

Just for reference, I can have a full night of comfy sleep at 45* with it and silk pj's.

Hummmm …

OK … I'm going to try this out.

I'm building a Forshell style Tunic quilt but with two layers of 3D. Finished weight I expect to be around 20 oz (I'm a big guy) but use with a VBL could very well take that quilt down (comfortably, although that seems to be a term to use with care here) to 20. My Heatsheets bivy (planning on using as a Vapor Barrier Liner) is 3.25 oz.

Assuming all other items remain constant:

Quilt/Tunic = 20 oz
Vapor Barrier Liner = 3.25 oz
Light insulated Vest to hike in/extra insulation = 6 oz.
Capilene silk weight bottoms = 6 oz
total = 35.25oz
vs

30 degree bag = 24 oz
bivy = 7 oz
Insulated pullover = 14 oz
Total = 45 oz

vs

Vapor Barrier Down Sleeping bag (1.75 inch loft with empty down panel on bottom)(estimated) = 16 oz
Insulated vest to hike in/sleep in/hang out in camp = 6 oz
(use VPSleeping Bag as additional insulation in camp)
Capilene silk weight bottoms = 6 oz

Total = 28 oz.

Having a guy like Bill Forshell, and all the others on BPL, around to spark so many great ideas …. Priceless. (Weightless?)

"I sleep for 6-7 hours with the help of a few shots of goldengrain- grain alcohol, which thins the blood and gets it to hands, feet and face"

Do you wake up cold and Hungover as well??

I think I can say I am finished with my Cuben – PrimaLoft One / Sleeping Bag.

The bag is made out of all Cuben Fiber. The bag in its present size is 19.08 ounces. I say present size since when making it I added some extra length to it. When I made my last prototype I lost some of its length. The non-insulated insert for the bottom is tapered and when I sewed it to the rest of the bag the taper pulled in the sides and made it shorter. I added 10 inches to the length just to make sure it wasn't short. The current length is 89 inches. I will decide how long I want it but I am thinking about 80 inches. When I do this I think the weight will go down to 18 ounces.

The bag uses two layers PrimaLoft One (Clo of 0.84) 1.8 ounce per sq yard pre-quilted insulation in the main bag. This gives me a total Clo of 3.02. I made a small hood for the bag that uses 3 layers of the same insulation. I also made a neck yoke and used 4 layers of insulation in it. I have elastic in both the hood and the opening of the bag. The bag is made to slide into. The circumference of the top part of the bag will open to 64 inches. The foot end (if cut at 80") will be 38 inches. The insulation is stabilized to the inter piece of Cuben so the shell has no seam lines to leak.

Yoke

Hood and Non-Insulated Bottom

Finished – Sleeping Bag after trying it out. The sleeping bag is made of 2 layers of PrimaLoft One – 1.8 ounce per sq yard pre-quilted insulation. The bag part has a total Clo of 3.02.

"Edited" Rolled up for packing.

Detail of Neck Yoke and Hood. The Neck Yoke is 4 layers (Clo of 6.04) and the Hood is 3 layers (Clo of 4.53) of PrimaLoft One – 1.8 ounce per sq yard pre-quilted.

Do you wake up cold and Hungover as well??

I don't get slammed… usually. A little nip of alcohol just helps keep the extremities warm. A large nip makes you forget where you are, but can cause lots of lost core heat. I'm pretty used to a slight chill. It goes away after I get up and moving. Hydration prevents hangovers. Low standards for comfort help too.

That sleeping bag looks awesome. Draft collar and a hood is a great touch. How do you think it will handle stuffing?

David,

I have rolled it tight 3 times so far. It just puffs back up. I need to get it 13.5" by 6.5" to fit nice in my pack.

I will roll and unroll it each day and see what happens. This stuff is supposed to be beyond compression problems. Time will tell.

Bill, if it's possible, send me your mail on Jonyk_7@ukr.net.
I cannot contact with you through PM.
Evgeniy.

Evgeniy,
Bill changed it back. I had the same problem when I wanted to send him something.
_____________________________________________________

Bill,
I have to commit one more time on this bag.
This the first bag I have seen with the Cuben used inside and out.
Although I think it has it's usage, the one I'm mostly thinking of is that it resembles an alien space-craft and you fly around in it.

Just watch out while you're flying around with that kilt on.