#1
Got a used semi hollow off eBay. The neck and body are in good condition but the owner lived in Florida and I am in the northeast.

Can I use an accoustic guitar humidifier? The one I have hangs from the strings so it is in the body. Would it help to just keep that in the case?

Is it worth it to get a humidifier for the room?

Could I have done any permanent damage by having it in a dry environment the last month?
#2
Unless you bought a very old or rare hand-carved instrument you don’t need a humidifier. Semi and hollow electrics are made of plywood to keep the wood from splitting. Good acoustic guitars need humidifiers because they’re made from a single strip of thin wood, and because the wooden bridges are prone to cracking.
#3
Semi-hollows generally will not have issues with humidity. On an acoustic, the issues are that the varnish and wood are very thin, and the glue joints are narrow and prone to opening up. None of those things are present on the average semi-hollow, so you shouldn't need to worry about humidity unless the guitar is in seriously harsh conditions. As long as you're playing indoors and not leaving the case in a cold car for long periods of time the guitar will be fine.

Still, if it makes you feel better, there's no harm in humidifying your case or instrument. You can use whatever humidifier you like, but personally I would not bother. Unless your guitar is some exotic model with super thin varnish and a really small center block you can basically treat it like a solidbody.
#4
Northeast winters can be alternately very dry and sometimes very wet, depending. If there's snow on the ground and the temps are low, and they're inside a warm house, chances are the air is very dry (unless you own a room or home humdifier).

A humidifier (barely damp sponge in a baggie with a few holes) inside the case wouldn't hurt; it's the neck that's the issue in a semi-hollow (as it is with solid bodies as well). If it dries out, your frets may begin to sprout or go out of level. Re-humidifying often doesn't help it; only a good fret level will fix those issues.

I have two things inside my cases -- the aforementioned humidifier and a vapor corrosion inhibitor (VCI -- check www.theruststore.com) that helps prevent corrosion. I usually wax all my guitars, both hardware and finish, very lightly mineral oil the fretboards, and you're good to go.
#5
I would get one for the room , this time of year in Ohio humidity is only 20 percent , the dry humidity seems to make the neck straighten out and loose relief , I've had to loosen the truss rod on all my guitars, every day seemed like the strings would go sharp , got a humidifier and that baby ran for days solid before reaching 50 percent humidity , now everything is back to normal and the guitars all stay in tune better now too .... it sure won't hurt anything having a humidifier
#6
My guitar is mahogony with a maple top. So is it a mahogany plywood? It is definitely not some special rare guitar that I'd need to be super worried about, but I love the guitar and would hate if it deteriorated. I also know the truss rod needs a tiny adjustment but am worried about doing that if the wood is dry.

If I bought a humidifier what % would be ideal?
#7
Quote by Playsabadguitar
My guitar is mahogony with a maple top. So is it a mahogany plywood? It is definitely not some special rare guitar that I'd need to be super worried about, but I love the guitar and would hate if it deteriorated. I also know the truss rod needs a tiny adjustment but am worried about doing that if the wood is dry.

If I bought a humidifier what % would be ideal?


Generally guitars like 40% or above.
#8
Quote by Playsabadguitar
My guitar is mahogony with a maple top. So is it a mahogany plywood? It is definitely not some special rare guitar that I'd need to be super worried about, but I love the guitar and would hate if it deteriorated. I also know the truss rod needs a tiny adjustment but am worried about doing that if the wood is dry.


The question I'd ask is: Is this a guitar with a molded plywood top/bottom, or is it one with a top and bottom that have been carved from single pieces of maple and mahogany. For example, an ES-335 has a molded laminated top, while a Carvin has been CNC carved, top and bottom. Gibson actually does BOTH methods with the smaller-bodied semi-hollows.
#9
Quote by Playsabadguitar
My guitar is mahogony with a maple top. So is it a mahogany plywood?


It might be. It might also just be one layer of each wood arranged with the grain perpendicular. There’s not a standard for this sort of thing.
#10
Quote by dspellman
Gibson actually does BOTH methods with the smaller-bodied semi-hollows.


Being a CNC machinist at Gibson Memphis, where the hollow and semi-hollows are made, I have not seen one top carved on a CNC. All semi-hollows and hollows, 195, 139, ESLP, 137, 295, 175, 335, 330, 339, 390 and various artist series and variants all have their tops and backs pressed from 3 layers of wood, then are cutout to shape by CNC.

Gibson Custom might carve a guitar like that, but since we ship out selected pressings to them on a weekly basis, I doubt it. About 90% of the pressings we ship to Custom are Dot-style, with a few 339 and 175 pressings.

Now we did do a solid maple prototype last year. I'm not sure what happened to it though. We do a LOT of prototypes. One of the cool things about working here is I can go upstairs and play around with some guitars that never saw production, or were changed prior to production. For a time, I had a prototype sitting by my work table. I'd play it a bit every morning before work.
#11
Quote by azrael4h
Being a CNC machinist at Gibson Memphis, where the hollow and semi-hollows are made, I have not seen one top carved on a CNC. All semi-hollows and hollows, 195, 139, ESLP, 137, 295, 175, 335, 330, 339, 390 and various artist series and variants all have their tops and backs pressed from 3 layers of wood, then are cutout to shape by CNC.


Does the CNC route a laminate block down to produce the arch shape? Or is the wood molded into the arch before the CNC machine cuts out the body shape and f-holes?