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Moisture in Caribou MF


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  • #1727379
    Dirk Rabdau
    Member

    @dirk9827

    Locale: Pacific Northwest

    Condensation can be explained by relative humidity. Relative humidity represents "the amount of water vapor present in air expressed as a percentage of the amount needed for saturation at the same temperature."

    As air cools, relative humidity increases. That is, for a 20 percent relative humidity at 86 F becomes 100 percent at 37 degrees. This is the dewpoint. Further cooling will result in the moisture being condensed. We see that all the time in the formation of dew.

    In the PNW, we get a fair amount of humidity. Not the hot humidity of back east, more of the wet, soggy, cool kind. And at night, when temepratures drop, you often awake to find your tent covered in dew.

    Well, sleeping bags can get this way too – as we recently had the great "down in the Northwest debate", the point was raised that down suffers for all of this humidity and loses its effectiveness over time. It's critical to dry out your bag. The only problem is that there are times when it's hard to find good enough weather to dry out your bag.

    Ryan Jordan of BPL did write a letter that addressed this. You can see the whole thread here: http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=39920

    His quote as cited:

    "I spoke at length with IDFL yesterday about down testing.

    None of their tests stimulate real world testing. 900 fp in a test is going to be a pipe dream in the field, because they steam wash and dry the down to nearly zero humidity before doing the test. Ironically, this most recent iteration of test methods was designed to determine the maximum possible fill power for down rather than what it will look like in the field.

    Interestingly as a side note, we did some 900 fp testing of down a few years ago on two manufacturer's 900 bags. We cut the bags open and sent them to IDFL. Neither made the claimed 900 spec (they tested 830-870 using the steam method). What was more dramatic was that when each down (which clearly came from different sources as evidenced by visual inspection) was subjected to 50% humidity, the differences were pretty dramatic. One bag tested at 770 fp, the other at 680 fp. It seems that at least these two sources of 900 down had feathers in it that were not resilient in response to humidity.

    The kicker is that we ran the same test next to down taken from a manufacturer's 750 fp bag. at 50% humidity, the fp was 720. Why? It had more feathers that were stiff enough to preserve the loft in moist conditions."

    #1727449
    scri bbles
    BPL Member

    @scribbles

    Locale: Atlanta, GA

    So after this thread and some browsing, I'm considering returning my NeoAir for the SynMat UL7. An additional 2oz but reviews are saying the Exped is superior.

    This leaves me with two questions: What temps could I comfortably get to with a Caribou/SynMat UL7? Is this pad too warm for summer/Should I keep the NeoAir for warmer weather?

    #1727460
    Steven McAllister
    BPL Member

    @brooklynkayak

    Locale: Arizona, US

    I personally would do as others have advised and keep the Neo and supplement with a thin closed cell foam pad. They can be had from 1/8" on up and are inexpensive.

    Some examples:
    http://gossamergear.com/

    #1727498
    Konrad .
    BPL Member

    @konrad1013

    I agree, more versatile/adaptable. Plus if the SHTF and your air mat pops, you still have a thin layer of ccf keeping you from the ground.

    But also, its a comfort thing so I guess you should try out both. You might like the vertical baffles more than the horizontal baffles, or vice versa. Personally, I'm waiting for the POE peak AC, and the new 4-season neoair to come out before I make a decision as to what my dedicated winter pad will be. Oh, and Roger's sleeping mat report will prove vital to that decision too (C'mon Roger! we're dying :D )

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