Modern Gretsch Guitars

Humidity Levels During Assembly


Hey guys, do any of you happen to know the humidity levels during assembly in the Japanese plants?

I'd like to buy some 2-way humidity packs for my Duo Jet. I was going to get the 49% one, but I read that the humidity level where it was originally built matters in terms of the most stability.


A buddy who builds acoustics says he wants the driest wood and conditions during the build. Then after, guitar then absorbs moisture from the air and everything tightens up.


What are the choices re: relative humidity measurements?

I'm familiar with D'Addario's humidifying/de-humidifying packs, but I think they only advertise a range of 45 to 50 percent relative humidity. And that's about what most guitar makers recommend, IIRC.


I was looking at these:

Mainly because where I live in CA the winter/rainy season is upcoming, and it gets much colder and wetter than the dry season (nice temp and humidity levels). I wasn't sure if I should get 49% or 58%. I wound up getting 49%.

I read on a luthier's site that the humidity it was built at should be matched. Ideally that seems right, but probably hard to do, but I'd at least like to get as close as possible.


Do you guys think electrics can benefit from these?

I'm nervous because my past few duo jets the neck warped. The rainy season is upcoming and that always gets me nervous. The summer has been usually humid, too.

I purchased a hygrometer today. I'll start there. But wondering if these 2 way packs would help in your opinions.

I know the homemade thing is to put a sponge in there if it's dry, but is there a homemade method for too wet?


A dehumidifier for the room where your guitars reside would be a good way to manage that situation.

IMO this is more of an issue for a flat-top or hollow-body guitar, because there is so much unfinished wood on the interior. That wood can quickly take on (or lose) moisture in a damp or dry environment.

Less of an issue with a fully-finished solid-body guitar, in my experience.


The Duo Jets are "chambered", so there is some hollow space in there. I'm only worried about that one, not my Fender solid bodies.

Do you think it's a non issue?

I will look into a dehumidifier, thanks man.


There is some misunderstanding about wood moisture and relative humidity. Wood is typically dried to around 8% moisture, but once it leaves the kiln it will adjust to the environment it is in. If you live in the desert southwest, it may get drier, here in humid florida it's more likely to be between 10-12% indoors, higher outside under cover.What wrecks wood objects is sudden changes in humidity, like what happens when you go from hot humid summer to ultra dry air in winter. Usually it's worse going ultra dry air, so a humidifier in a case would be wise in that it slows the change down , but unless you keep your guitar in one place that's climate controlled 24/7, it's gonna acclimate to where it is. Finish will slow down that change, but that's it.A humidifier in the case ,same thing. Generally, woodworkers build with this in mind, it's why things evolved construction wise the way they did, it allows for some movement. But as mentioned , acoustic instruments get hit the hardest, all that unfinished wood inside really changes quickly. I have a 50's tele whose neck is particularly sensitive to change, I find myself tweaking that one often, but generally my other ones behave pretty well. As far as what the plant humidity in Japan is, that should be the least of your worries. If you knew the crazy fluctuations that happen in those shipping containers you might never get another good nights sleep.


Thanks, Opie. Interesting and good info. So I case it all year round when not using it, and I live in California area where it's about mid 70s temperature all year, but humidity varies a lot. Do you think if I just keep it cased it should be fine? This past summer has been unusually humid, and we're about to hit the rainy season in a month. Just not sure if I should do anything like a 2 way packet in the case or dehumidifier.

I will see what the hygrometer reads once I get it, and that might help make decisions. Humidity has been in the 80s this summer, and 50s to 60s is more normal. I'm not sure what 80 humidity outside translates to inside the apartment or the case itself.

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