Taking My -20 F. down bag to -40 F. ... maybe

Discussion in 'Backpacking Gear & Clothing' started by Litehiker, Dec 14, 2017.

  1. Litehiker

    Litehiker Well-Known Member

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    Last year I bought an LL Bean -20 F. goose down mummy bag. Excellent design and quality and it was on a huge one-day, double sale for $265. or so. Free shipping.

    It was fine at -10 F. but I have a chance to go to either Montana or North Dakota this winter and I'd like to test it to -40 F. (in my solo tent) if I get the chance.

    So here is my setup:
    1. -20 F. LL Bean goose down bag
    2. Thermarest TrailPro self-inflating mattress
    3. Ridgerest closed cell mat (under the Trail Pro)
    4. polar weight polyester long johns
    5. fleece balaclava
    6. heavy sleep socks over thin poly liner socks
    7. Eddie Bauer light down jacket
    8. Montbell light down pants
    9. thin knit polyester liner gloves (they really help)
    10. Psolar face mask (warms air W/ layered copper screening that's warmed by exhalations) This is now out of production.
    ** May keep my Norwegian wool sweater on under the puffy.
    ** I might try using a Vapor Barrier Liner of pants and shirt made from waterproof silnylon. I'll wear it over the long underwear for comfort. This keeps heat-robbing sweat vapor out of the down bag and clothing. On a multi-day trip a VBL suit in these temps is mandatory.

    So with those clothes I think I'll be able to take my -20 F. bag to -40 F. I've taken my +20 F. Western Mountaineering Megalite down bag to +5 F. with synthetic puffy clothes with good comfort. But,yeah, -40 F. may just be a different animal. Only been in -40 F. once in my life in 1979. I've slept in -22 F. in a snow cave but they are much warmer than a tent.

    Eric B.
     
    Last edited: Dec 17, 2017
  2. squeezenhope

    squeezenhope Well-Known Member

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    Got a chuckle out of your post. -40 maybe hard to come by in the lower 48. At least I hope so!
     
  3. Alaska2006

    Alaska2006 Well-Known Member

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    Well get over in Western WY. and -40 will find you pretty quick right around Thanksgiving for about 7-10 days and again in late Jan. for about two weeks. You can find -20 there about any day without even looking for it.
     
  4. Litehiker

    Litehiker Well-Known Member

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    squeeze,
    I've experienced -40 F. in 1979 at Lake Placid's Van Hovenberg Nordic ski area as a Nordic patroller for the Pre-Olympic World Cup games. Needless to say all events were cancelled that day.

    I've slept in a snow cave at -22 F. in Erie, PA but a snow cave temp is usually never below the mid 20's F. due to the excellent insulative value of the snow.

    I do have a very good idea of -40 F. since I had to stay out in those temps for 3 hours until we patrollers were called in when it was decided the temps were not going to rise that day. Thankfully I had all the right clothes including Dachstein boiled wool mittens inside my nylon mitten shells and foam booties over my non-insulated XC boots.

    Alaska, I believe you regarding Wyoming's -40 F. temps, ESPECIALLY in the Rockies above 7,000 ft.

    Eric B.
     
  5. squeezenhope

    squeezenhope Well-Known Member

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  6. squeezenhope

    squeezenhope Well-Known Member

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    Whoa boys, I never said it does not get -40 in the lower 48. I just said it is hard to come by. It's even more difficult to schedule. There are many years when it does not get that cold in Wyoming, at least where they have weather stations.
     
  7. T.Rep

    T.Rep Well-Known Member

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    Several years back I was working in North Dakota and was out in -50 wind chill, actual temp was -30ish if I remember right. I cant imagine trying to sleep in that. Any exposed skin literally felt like it was on fire. Good luck to you.
     
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  8. Barrelnut

    Barrelnut Well-Known Member

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    May sure you can still fit in your bag with all that stuff on. You need air circulation in there too.
     
  9. ssssnake529

    ssssnake529 Well-Known Member

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    This is true. I always get sleeping bags with extra girth so that I can wear my warm, puffy clothing inside them comfortably. Just make sure you will fit in the bag with all that warm clothing on. If you can fit, then I think you will be fine at -40 with the clothing and bag that you listed in your original post.

     
  10. Litehiker

    Litehiker Well-Known Member

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    ssnake,
    I've put on my base layer and puffy layer to see if the bag was large enough. It was fine and neither my bag nor puffy were compressed. In fact I was surprised how much space my legs had with all these layers.
    These layers and the great collar on this bag will make it very efficient. I need to test it at or near -20 F. with only my base layer of "polar" weight polyester long johns, heavy sleep socks and fleece balaclava. If the bag is OK at or very near its limit then I will know it will likely be good at -40 F. with the puffy layer. (fingers crossed)

    Eric B.
     
    Last edited: Dec 23, 2017
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  11. PBramble

    PBramble Active Member

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    So, I have to ask, because I spent last night in the teens in a -40 bag with pjs, a long sleeve t and a balaclava. I was still chilly at about the 5 hour mark. It just got worse from there. Set up was bag on an air mattress on foam pads in a truck bed. Condensation froze in the camper shell, on the face mask and some ice had formed on the outer side of the bag. Is it really a -40 bag if I get cold wearing extra clothes when it's 15*? Do I expect too much to be able to climb into a sleeping bag with pjs and stay warm?
     
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  12. Litehiker

    Litehiker Well-Known Member

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    Bramble,
    That sounds like a bag problem B/C it should have kept you warm as toast with teens temps. Last winter my -20 F. bag kept me nice and warm at 12 F. in my solo Moment DW tent.
    ->Did you wear a head/neck covering? If not try it again with a fleece balaclava.
    ->Your air mattress is conducting heat away from you unless it is a Thermarest NeoAir X-Therm.

    I recommend you get the least expensive foam filled, self-inflating Thermarest type mattress over your foam pads. But try to make sure the foam pads are closed cell like the Themarest Ridgerest roll-up or Z-Rest folding pads or military roll-up pads. I use a Thermarest Trail Pro on a closed cell foam Ridgerest at -5 F. and am always warm. That combo is truly good at -40 F. with the right bag.

    As others have mentioned here and in other winter hiking forums, being warm in a -20 F. bag at -20 F. may not work without an additional puffy layer over my polar weight polyester base layer. To be warm at the bag's lowest rated temperature, even with my heavy weight base layer, would require that I have a basal metabolism of a champion endurance athlete or wrestler. But at 74 that ain't gonna happen. My doc says i'm in "excellent condition" but she means excellent for a 74 year old, not a 40 year old.

    So, yeah, I backpacked the Grand canyon for 4 days this past November from the North Rim down to the Colorado River and up to the South Rim but it was a grind going up. A bit more difficult than it was even 7 years ago. Ya can't defy age, just slow down the process.

    Eric B.
     
    Last edited: Dec 24, 2017
  13. Mike 338

    Mike 338 Well-Known Member

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    Truck beds are from hell. You mentioned air mattress. A plain air mattress is a cold set up in the summer. A very comfortable air mattress may have poor R-value. Gotta check that out before you purchase it. The R-value of most foam pads is slim to none so I'm guessing you had a very cold metal truck bed with poor foam insulation, an air mattress next to you that's almost guaranteed to make for a chilly night and a good bag with good insulation on top but still compressed under you so your kind'a suck'in up that cold truck bed through the bottom. If it's in the teens, it's already a lot colder than sleeping on an ice cube.

    Your pad basically is your sleeping bag on the underside of you. They make all kinds of good cold weather sleeping pads. It's pretty much a matter of writing a check. For a cold weather pad, you should be able to put your hand on it and feel the warmth radiating back on you. If your in a truck, weight isn't a factor so a guy could have both great comfort and warmth. You can also layer pad upon pad to up your R-value incrementally. A closed cell foam pad with an R-value of 1, under a good pad with an R-value of 6 will give you a cumulative R-value of 7. A cheap closed cell pad under a nice pad will protect the good pad and add more R-value. Good pads will publish the R-value of the pad.

    For all that crazy condensation you get in a truck shell, you can get a gore-tex military surplus bivy sack. They're not as expensive as you'd think. You'll get a little condensation inside from your own body but the heavy stuff will be outside on the bivy.
     
    Last edited: Dec 24, 2017
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  14. PBramble

    PBramble Active Member

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    I'm pretty sure you've hit the nail on the head. It is a cheap foam pad and I was using a Coleman air mattress. It was good for about 3-4 hours, but then I got cold and I could feel it coming from under me. I basically slept in decent over the calf socks, light weight base layer top and bottom, flannel pj bottoms, a long sleeve t shirt and a fleece pullover. I had to use my ski mask beanie when I woke up and my face was burning from the cold. While it was cold, it was not near as cold as when I got up and got outside. Since I'll primarily be using the truck as base camp, I've been looking into 4" foam (not memory foam) folding mattresses. Figure I should be comfortable as I can while I'm roughing it. I'll look at the bivy sack too. Guess I'm expecting too much from the manufacturer's claims. Thanks for the input.