Humidifying a Plywood Guitar?

Bounty Hunter

Gretschie
Apr 29, 2010
112
Illinois
A recent thread reminded folks about humidifying guitars in the dry winter season and although I've always kept my solid wood acoustics in their humidified cases I have never worried about my plywood guitars (acoustic and/or electric) However, I recently bought a sweet Brian Setzer Hot Rod and it's my first high end Gretsch.

My thought is although it's a very, very nice guitar it's still plywood and I shouldn't worry too much about it drying out. Please educate me if I'm wrong because I don't want to cause damage. I've owned a few Electromatic models in the past and never saw any damage due to my not humidifying them. I do know that the Electromatics are 5 ply and the Japanese models are 3 ply, if that makes any difference in their care. TIA!
 

afire

Friend of Fred
Feb 12, 2009
5,968
Where the action is!
I've never humidified any guitar. It's probably the source of a lot of problems I've had with acoustic guitars, but I've never noticed any issues with my electrics, mostly laminated hollowbodies. I've never noticed seasonal changes that required adjustment, and certainly never any actual damage. Others may disagree, but I don't think it's anything to worry about.
 

AZBrahma

Synchromatic
Dec 18, 2020
730
Arizona
I'm with afire. I haven't humidified a guitar in 25 years, the last being a nice Spanish classical I had at the time. Really no electric guitar should really need it, if anything I can really only see a case for an electric to be de-humidified because it was somewhere very damp. To order your question more directly, I wouldn't bother. Laminated wood (plywood) is pretty much impervious to basic humidity differences.
 

Ricochet

Senior Gretsch-Talker
Gold Supporting Member
Nov 13, 2009
22,738
Monkey Island
Get a good Hygrometer. If the humidity levels are comfortable for humans(between 20-60%) it's fine for your guitars. And I agree, wood is not wood. :)
 

G5422T

Country Gent
May 24, 2012
4,225
usa
So many variables to consider.

Your climate, temperature extremes, Seasonal changes, how do you heat/cool your house, and....

Where do you keep/store your instruments.
 

LivingMyDream

Friend of Fred
Gold Supporting Member
May 4, 2016
6,946
Peculiar, Missouri
I've had a few "laminate" acoustics and never humidified them. When I bought a solid wood Epiphone Masterbilt and a solid wood Taylor, I also bought a D'Addario humidification system for each guitar and have been using them for years. I never have any issues with my solid wood guitars, and I can feel the packs bulking up when weather gets more humid, and then thin out when the weather is dry. One pack in the sound hole and one in the case at the headstock.
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loudnlousy

Gretschified
Gold Supporting Member
Oct 18, 2015
12,713
Germany
There are a lot of members here that live in a climate of extreme humidity- and temperature- changes where I would very strongly recommend to use a humidifier on any wooden instrument. Although plywood should stay stable even in the most adverse climatical circumstances controlling the humidity will not hurt. Especially when some of the the instrument`s parts are not plywood, like the neck.
 
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thunder58

Super Moderator
Staff member
Double Platinum Member
Dec 23, 2010
27,626
Tappan N.Y.
There are a lot of members here that live in a climate of extreme humidity- and temperature- changes where I would very strongly recommend to use a humidifier on any wooden instrument. Although plywood should stay stable even in the most adverse climatical circumstances controlling the humidity will not hurt. Especially when some of the the instrument`s parts ar not plywood, like the neck.
Well said and agreed ;)
 

DougWheeler74

Synchromatic
Jul 10, 2019
742
NE Wisconsin, US
Where I live it can be in the high 90s and oppressive humidty in the summer and subzero and bone dry in the winter. My house is heated via radiators, no central AC or humidification. My music room is the first to get a window AC in the summer and a humidifier in the winter. Heck, my skin actually cracks in the winter. I've had a solid body experience fret sprout until I started humidifying it.

As stated, someone else's experience may be different.

As to the actual (in my opinion) question, plywood is a combination of sheets of wood and glue. I worked at a wood research facility for 5 years where we tested a variety of composite wood structures and yes, some warped with humidity changes. Wood is non-homogeneous, every piece is different. I once had the opportunity to play 5 different Martin HD 35s and they all had their own voice. One guitar may show humidity issues while a different one may not.

In research the motto "One test is worth 10,000 expert opinions" may apply here. My advice is to pay attention to your instrument(s) and react accordingly.
 

oneforsorrow

Country Gent
May 15, 2020
1,159
Iowa
I have a’71 Guild Jumbo. It’s solid wood so it doesn’t qualify as plywood. However, I thought I’d share my experience. For years I didn’t humidify it. No noticeable problems appeared and I was blissfully unaware. At some point along the way, I was told to humidify and started doing so. However, a couple of years ago, I had to have some cracks cleaved. Nothing too serious but I’m fairly certain this could’ve been avoided had I taken better care of it all along.
 

ronbo

Gretschie
Feb 28, 2012
440
Broomfield, Colorado
For the most part, laminate electric guitars will remain stable unless they experience big changes in temperature and humidity. Many hollow bodies still have solid wood neck block, which can be affected, causing a hump in the frets where the neck meets the body, causing some buzz in that area. This is very common in solid wood acoustic guitars and requires some fret leveling in that area. I use Oasis humidifiers in my acoustic guitar cases, which are cheap and reliable and haven't had an issue in over 10 years.

The main issue with electrics is fret sprout, where the fretboard dries out and shrinks, leaving the fret ends exposed a bit. A simple and fairly cheap problem to fix and (generally) once fixed, it doesn't shrink that much more. Stewmac has the tools and videos to walk you through the process of filing down and polishing the fret ends, which is what I do. I have seem rosewood fretboard crack due to dryness, so I also oil my fretboards with lemon oil about twice a year and that seems to keep things in check...
 

afire

Friend of Fred
Feb 12, 2009
5,968
Where the action is!
Really no electric guitar should really need it...
I think the only exception to this would be solid top electrics. I.e., something like an L5CES. The last expensive acoustic electric I owned for any length of time was a Gibson J-160E solid top. I rarely used it and one day took it out of the case to find a nice big crack in the top. I don't know what could have caused it other than environmental circumstances and my failure to account for them. And knowing how many old carved archtops have repaired cracks, I would be inclined to be cautious if I had a bunch of money tied up in one.
 

j.s.c

Country Gent
Aug 19, 2008
3,661
france
I saw very few plywood guitars with cracks but I saw it with my eyes... For instance some plywood guitar isn't = to another... in the '50, Gretsch used regular 3 ply where Harmony used 3 ply but a sandwich of 2 thin and a thicker one in the middle, then it's closer to plain wood characteristics and if you expose it to high variations of temp/humidity then I will crack.
 


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