Gibson nitro finish checking, J 100: Poll

Discussion in 'Acoustic Instruments' started by 84superchamp, Dec 27, 2017.


why is checking occurring on a 21 YO acoustic guitar?

Poll closed Jan 10, 2018.
  1. it's normal at 21 years old.

    10 vote(s)
    76.9%
  2. it isn't normal, something is wrong with the storage "atmosphere".

    3 vote(s)
    23.1%
  1. 84superchamp

    84superchamp Silver Supporting Member

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    I'm wondering what the normal time frame is on this? Pre-mature would indicate more care should be taken in storage, i presume?
    According to the ser#, this is a 96, 21 years old. Too soon? The storage (playing) room isn't kept at a constant temp; i turn up the heat when i'll be there for a while but otherwise, heat turned down and chilly but certainly not freezing (which is what i've heard will speed up checking). Anyone familiar with the process?
     
  2. snakestretcher

    snakestretcher Member

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    A friend has a '57 J200 with crazed nitro all over. This usually occurs if the instrument is subjected to rapid temperature change, as you mention. I have no idea if it is age-related. Around 10 years ago I owned a Martin D-28 from 1984 and the finish was fine.
     
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  3. TheoDog

    TheoDog Silver Supporting Member

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    I think you have a storage/environment cause.

    A drop in humidity that we experience in the winter saps moisture from wood instruments causing issues like popped glue joints and fret sprout.
    But also allows the air temp to change much more rapidly which is what causes a nitro finish to crack as it expands more quickly than the wood it is covering.
    I think :dunno

    The wood of the older guitar is likely as dry/settled/seasoned as it will ever be, and if the finish hadn’t already experienced the dramatic change by now, it would have been possible to keep it intact indefinitely.
     
    Last edited: Dec 28, 2017
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  4. 84superchamp

    84superchamp Silver Supporting Member

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    Thanks guys.Theo, i was a bit late getting my portable humidifier going this year...that was a fast temp change this year from 40s to single digits F in a short time.
    Finish checks are pretty common but i'm wondering what the next step in degradation is, assume it's cracking. :eek:
     
  5. alamere

    alamere Supporting Member

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    If the room is constantly fluxing in temp, especially swinging as far as 30 degrees back and forth.. zero doubt that will check the guitar and long term, yep.. I'd expect cracking also. It's an easy solution though. Store the guitar somewhere with a more consistent temp. Especially with acoustic guitars.. in my opinion, they're pretty damn portable. ;)
     
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  6. snakestretcher

    snakestretcher Member

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    Golden rule; if you feel comfortable in your environment, your guitar also will. My guitars live in my living room, on wall hangers out of the way of visiting small kids, dogs and anything else remotely threatening.
     
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  7. 84superchamp

    84superchamp Silver Supporting Member

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    I agree, and it may be a mistake to keep the room chilly until i'm ready to spend some time there, then turn up the heat. Since discovering this, i am leaving the thermostat alone. Saving a little on the heat bill isn't worth the possible consequences.
     
  8. Axis29

    Axis29 Supporting Member

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    Yup, quick temp and humidity swings will kill nitro finishes. The guys use the cold from upside down cans of compressed air when they relic guitars.. Same concept.
     
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  9. swa

    swa Member

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    My '95 J100 isn't noticeably checked. It lives with me, in the same rooms, but I don't really baby it, I just keep it in the case when not being used, and it gets pretty cold in NH?
     
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  10. 84superchamp

    84superchamp Silver Supporting Member

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    It's odd when it comes to this finish checking. Evidently a small variation somewhere, somehow, accelerates the proceedure. The biggest concern is if it advances from checking to cracking...i've become real attached to these acoustics.
    Oddly, i have a cheep Dixon that goes thru some real torture care-wise, kept in my pole bldg that regularly goes from 35f to 75f and the finish is almost perfect.
     
  11. Jabberwocky

    Jabberwocky Member

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    Nitrocellulose lacquer with little plasticisers in it is like eggshell. Dries hard and thin. Old formulation nitro is like that. New formulation with plasticisers are a lot more flexible but rubbery and does not seem to harden. Eggshell nitro lacquer has much less of a damping effect on the guitar. It enhances it, in fact.

    It is pretty difficult to keep nitro unchecked unless you do not take it out of your house and keep it in a very stable environment where the temperature and humidity hardly fluctuates. And even then, as wood continues to season the mechanical stress gets worked out it and into the nitro lacquer and it checks.

    I won't sweat it.
     
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