why are certain guitars more affected by humidity changes?

Discussion in 'Guitars in General' started by patshep, May 29, 2020.

  1. patshep

    patshep Supporting Member

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    I've had a bunch of guitars, and a few that never seemed to be affected by the seasons, barely needed a truss rod wrench at all, others freak out at the first sign of rain... I don't get why, similar woods, similar quality work, but maybe its dumb luck? thoughts?
     
  2. Dr. Tinnitus

    Dr. Tinnitus Member

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    Mainly the type of wood. Fender necks typically use maple, which is much harder than mahogany, used by Gibson.

    Mahogany is softer and more sensitive to humidity changes.

    Also, heel truss rod adjustment necks seem to stay put more so than headstock adjusters.
     
  3. Tim Plains

    Tim Plains Member

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    Trying to understand wood is like trying to understand human behaviour.
     
  4. Scary Uncle G.

    Scary Uncle G. Member

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    Every piece of wood is different just like every person.
     
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  5. patshep

    patshep Supporting Member

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    I always thought heel adjustment was so stupid, but you may have a point
     
  6. Benz2112

    Benz2112 Supporting Member

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    Neck wood material, thickness of the neck, type of truss rod, material of truss rod, how dry the wood was at time of production, and how the neck blank was formed (quartersawn, riftsawn, etc), all contribute to the stability of a neck.
     
  7. Guitarworks

    Guitarworks Member

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    OP, It's actually not difficult to comprehend at all. Necks made from closed pore species, like maple, are far more stable than necks made from bigger more open-pore species like mahogany, which tend to shift wildly with swings in climate, causing lots of tuning issues and needed adjustments for action (unless you have a stick of mahogany that is going to be more than an inch thick at the 1st fret when the neck is finished). It's why you never see necks made from ash - a nice solid dense material that is great for bodies, but has lots of big open pores. It's also why all my builds have a 3-piece laminate maple neck. It's very stable against any kind of twist, warp or bow with climate difference, and rock solid for intonation, but is highly responsive even to just a 1/8th turn of the truss rod, on the off chance that you want to increase or decrease the relief just a touch.
     
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  8. DrumBob

    DrumBob Gold Supporting Member

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    That's it in a nutshell. Every piece of wood is different.
     
  9. grendel

    grendel Silver Supporting Member

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    My main guitar seems to change even just when it gets foggy. It will go fully out of pitch with a bit of humidity in a matter of minutes it seems.
    My reaction has always been a sarcastic "Really?" statement to my guitar... lol
     
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  10. Dana Olsen

    Dana Olsen Gold Supporting Member

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    I agree completely. I have a bunch of guitars, made out of a bunch of different woods. Some of the necks move more when the humidity changes, some move less - but there's no one formula that applies to mahogany, maple, limba, etc as a species of wood. My old 335 will go years w/o needing a truss rod tweak, but my Les Paul R8 moves with the humidity on just about a one-to-one ratio, and they're both mahogany necks w/ rosewood fret boards, finished in nitro - LOL. The 335 is a '59, the R8 is a 2007.

    My Tom Kelley maple neck Tele, made in 2017 is pretty stable, but my real '56 refin Esquire w/ maple neck moves if you breathe heavy on it - I practically have to adjust it between sets - another LOL.

    I lived in the low hills several miles from the ocean for 15 years, then we moved just under half a mile from the ocean and about 30' above sea level a few years ago. Now ALL my guitars act differently than they did before, because of the higher humidity and bigger sways in the humidity levels.

    IME, guitars all act and react to the environment as individuals, not as species of woods. Some of my old ones are real stable, some move a lot. Some of my newer ones are real stable, and some move a lot. Some of the mahogany is stable, some of the maple is stable, and some move a lot - go figure.

    Thanks, Dana O.
     
    Last edited: May 30, 2020
  11. Scary Uncle G.

    Scary Uncle G. Member

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    Yes. I have an ES-335 that might have needed a slight adjustment once in the 11 years I’ve had it. OTOH, you breath on my Firebird and it needs an adjustment, despite being a 9-ply laminated neck through build.

    Worst was my Japanese made “50’s” Telecaster. Huge, deep solid maple neck so you’d think it would be stable. Nope! First year I had it, within a few days of the heat coming on in the house, the relief went from about .012 to nearly 1/4”!
     
  12. Kmaz

    Kmaz Member

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    I like the idea of heel adjustment, but just believe that it should have been made more accessible.
     
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  13. patshep

    patshep Supporting Member

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    i just realized, my epiphone sheraton ll had a maple neck, this may be why it was so much less finicky than my 335s have been...
     
  14. patshep

    patshep Supporting Member

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    I wonder if it has to do with the humidity where the trees lived?
     
  15. soulman969

    soulman969 Member

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    Or at least female human behavior. ;)

    Why have some of my kitchen cabinet doors warped while others have not? Why do some door frames swell and make doors difficult to shut? Why do various examples of the exact same guitar not sound alike? No two pieces of wood are precisely identical to one another.

    One of my basses needs to be kept humidified on a daily basis or after a week without it the neck moves enough to require tweaking. Two others with much thinner necks but also all maple just shrug the low RH off and keep on plugging away even staying in tune.

    I have an acoustic with a mahogany neck that also seems to tolerate a lack of humidity better than another that does not. I do tend to keep all of mine humidified as much as possible and some are just more stable than others even with identical necks. Wood....it's the only explanation I have.
     
  16. clint

    clint Member

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    I notice it more on maple necks vs maple with rosewood fretboards. Also, I have a roasted maple neck, rosewood board that never moves and barely goes out of tune.
     
  17. Tony Done

    Tony Done Member

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    My experience is that a most of it is about individual guitars, as noted by others, but some designs are more stable than others. My lap steels stay in tune for years. :D
     
  18. Jim Soloway

    Jim Soloway Member

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    I own a pair of Emerald graphite/carbon fiber guitars. Both the necks and fingerboards are graphite. I live in a place with really extreme climate and it's remarkable how stable they are. They've gone through swings from 7% humidity to 75% in a day and from 40 degrees F to 85 degrees in a few hours with no heat or air conditioning in our home and stayed perfectly in tune.
     
    Last edited: May 30, 2020
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  19. fjblair

    fjblair Silver Supporting Member

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    I've never had an electric that was sensitive to humidity. With acoustics I've only had issues with new guitars. Old ones don't really seem to notice.
     
  20. Corinthian

    Corinthian Member

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    If it’s humidity affecting the wood how is it getting through the finish? Are you sure it’s not swings in temperature that are causing the instability?
     

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