Moisture buildup underneath MBP

Discussion in 'MacBook Pro' started by thatguysmells, May 6, 2010.

  1. thatguysmells macrumors regular

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    #1
    I use my 13" MBP in bed on my lap while on top of a large hard cover book. After I use the laptop for about 20 minutes or more, I lift up the computer and the blanket is wet. Under the book is wet and around the lap top is wet. Is this condensation building up? The air temperature in my room isn't even that cold. This is really strange but condensation is the only thing I can think of. The problem doesn't seem to occur on a desk or table. It only happens when I use the laptop on my blanket. I'm not sure the fabric of the blanket but it kind of feels like a polyester. :confused:
     
  2. MrCheeto macrumors 68030

    MrCheeto

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    Nov 2, 2008
    #2
    Somebody is sweaty or didn't leave the bed spread on the line long enough :p
     
  3. thatguysmells thread starter macrumors regular

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    #3
    Ya no. Not the problem. Does anyone have a real answer?
     
  4. miles01110 macrumors Core

    miles01110

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    #4
    It doesn't have to be "cold" for things to condense. That's almost certainly what's going on.
     
  5. mkrishnan Moderator emeritus

    mkrishnan

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    Location:
    Grand Rapids, MI, USA
    #5
    I don't understand the physical arrangement of the things involved... is it like this?

    MBP
    ----
    book
    ----
    blanket
    ----
    your lap

    ?

    And where is the moisture? Both between the MBP and the book, and between the book and the blanket? What kind of environment do you live in? It seems hard for me to imagine that the MBP's surface is generating that much condensation, that it not only gets the MBP wet but also the water spills over the book and gets the blanket wet, too....
     
  6. thatguysmells thread starter macrumors regular

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    #6
    Ok the set up is this:

    MBP
    Book
    Blanket
    lap

    ^In that order.

    The moisture is appearing underneath and around the book. So moisture between the book and the blanket and around the book. If I don't use the book, the moisture occurs between the MBP and the blanket.

    I should note that my lap is NOT SWEATY AT ALL. And the room temp is not that cold, windows shut.

    If it is condensation, why doesn't it occur on a desk in the same room? The blanket seems to be the culprit causing the condensation. Why would a blanket do that?
     
  7. moel macrumors 6502

    Joined:
    Nov 7, 2007
    #7
    Where the hell are you for the air to be THAT humid?
     
  8. thatguysmells thread starter macrumors regular

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    #8
    I live 2 blocks from the ocean. And my room faces the ocean. La Jolla, CA.

    But, like I said, my window is shut! Is the air inside my room still moist even if the window is shut?
     
  9. square one macrumors newbie

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  10. thatguysmells thread starter macrumors regular

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    #10
  11. kgeier82 macrumors 65816

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    #11
  12. miles01110 macrumors Core

    miles01110

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    #12
    Because a blanket has decidedly more surface area on which moisture can build up than most desk materials. It also has different insulation characteristics.
     
  13. mkrishnan Moderator emeritus

    mkrishnan

    Joined:
    Jan 9, 2004
    Location:
    Grand Rapids, MI, USA
    #13
    Hmm, that's a pretty low humidity, although the air is cool enough that there's a big differential between the Mac's temperature and the air (the combination causes a lot of condensation).

    If the moisture is more between the book and the blanket than it is between the Mac and the book, I would go back to suspecting sweat... honestly, in Northern Florida (which is much, much more humid than SoCal), getting that kind of condensation off a metal notebook isn't something I've heard of much.
     
  14. thatguysmells thread starter macrumors regular

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    #14
    My legs and lap are completely dry. No sweat at all. No noticeable moisture in the room either.
     
  15. velocityg4 macrumors 601

    velocityg4

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    Dec 19, 2004
    Location:
    Georgia
    #15
    I don't really see how the laptop could be getting condensation at all. Since when running its surface temperature should be greater than the ambient temperature. Is the book in a freezer before being placed under the Macbook so that the book allows for condensation:p?
     
  16. thatguysmells thread starter macrumors regular

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    #16
    Nope. Everything is room temperature.
     
  17. DesignerOnMac macrumors 6502a

    DesignerOnMac

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    Jul 23, 2007
    #17
    Since the temperature is around 65 degrees, have you tried the combination without the blanket?

    Have you considered getting a laptop stand with a fan inside?

    The condensation is not coming from the computer. If the blanket is polyester, then it is trapping any moisture that is coming off your skin. Just because your not sweating does not mean moisture from your body isn't happening. Especially since you say that this does not happen on your desktop.
     
  18. thatguysmells thread starter macrumors regular

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    #18
    If that were the case their would be moisture under the blanket where it contacts my skin. Which there is not. The moisture is on top of the blanket.
     
  19. drambuie macrumors 6502a

    Joined:
    Feb 16, 2010
    #19
    That last resonse explains it. Human skin is always evaporating moisture, even if it's dry to the touch. In your case, the moisture penetrates right through the blanket, but condenses under any barrier on top of the blanket, whether a book, or laptop. If you put a plastic bag on your lap, below the blanket, I would suspect that the underside of the bag would get moist. If you have no heat on in your room, the humidity level in the room is probably high enough to prevent evaporation when the moisture hits a barrier.

    In colder climates requiring insulation, a plastic vapor barrier is placed between the interior wall material and studs. This prevents moisture from penetrating the insulation and condensing on the inside of the outer wall, resulting in soaked insulation, and possible wood rot.
     

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