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  1. #1
    Join Date
    Jan 2019
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    RELATIVE HUMIDITY IN GUITAR SHOP / how to nail reading

    my new humidity controller reads 7 % difference from my Honeywell humidity meter reading ....?? I need to set up my new controller to keep a constant 48% in my guitar shop, but I believe the new controller will need calibration to read exact / accurate relative humidity ....how do I measure that in my shop ?? (without having to fabricate a psychrometer from 2 thermometers) ....I ordered a mini dial type hygrometer hoping that tells me exact / accurate reading ...pics attached, THANK YOU FOR THE HELP
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  2. #2
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
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    You need an accurate temperature gauge. Calibrate with ice water, 32^F. Note the adjusted temperature. Next take a metal vessel with warm water and slowly chill with ice until exterior metal fogs, this is the dew point. Using a psych chart, lookup the %RH of the air using the air temperature and dew point of the air. An example is 75^F air that fogs a metal vessel with 55^F water is 50%RH.
    Repeat calibration every week.
    Make sense?
    How are you going add or remove moisture from your shop. I would like that big gray instrument on the top rail. Where is this shop?
    Regards Teddy Bear
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  3. #3
    Join Date
    Aug 2002
    Location
    Southold, NY
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  4. #4
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    Jan 2019
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    Thread Starter
    thanks for the assist, may go this route once I get reading off my hygrometer in my shop and compare RH numbers, I also found how to calibrate my new controller so I'll play with that as well ....my shop is in Whidbey Island WA, and that primer'ed big body is my '63 Silvertone, which I replaned the fingerboard and refretted, now I have to wait for warm weather to shoot its new paint ....not parting with this guitar for many years, my kid may sort that out per my instructions after I'm gone ...haa ha ...thanks again -

  5. #5
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    Jan 2019
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    Thread Starter
    hey pecks, where do I obtain this psychrometer ?? .....

  6. #6
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    Jan 2019
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    Thread Starter
    I meant pecmsg, auto correct did me wrong

  7. #7
    Join Date
    Aug 2002
    Location
    Southold, NY
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    I believe granger carries it

  8. #8
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    Jan 2019
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    Thread Starter
    I see Grainger sells a bunch of types of them, got it ....is this type of psychrometer THE way to nail exact / correct humidity in my shop ?? .....

  9. #9
    Join Date
    Aug 2002
    Location
    Southold, NY
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    I’ve had mine 20+ years. Haven’t failed yet, no battery’s needed!

  10. #10
    Join Date
    Jan 2019
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    Thread Starter
    ordered one !! will pick up at my local Grainger store tomorrow ....

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