Re-humidifying my Guitar

[Markbnj]

I've got a 1974 Martin D18 that I've owned for about twelve years. Recently it developed cracks along the grain on the top between the bridge and the strap. After reading up and talking to my local shop I concluded these were a symptom of low humidity in the house. On Saturday I bought an in-body humidifier, consisting of a perforated rubber hose with some absorbant material inside, and a plastic dome that wedges under the strings and seals the sound hole.

My question is how often do people think the moisture in the humidifier should be recharged? The instructions don't say anything about it. I was thinking an initial treatment period of 4-5 days in case, before I take it out and re-wet it. Any acoustic owners deal with these things before?

 

[lxskllr]

Don't know about guitars, but for wood in general, you want to move slowly. After a couple days with the sound hole sealed, I'd remove the cap, and leave it loose in the guitar. Get yourself a cheap hygrometer and measure the humidity. Adjust your wetting to keep a constant good level, whatever that may be.

 

[The Boston Dangler]

i'd be concerned about introducing rot

 

[dave_the_nerd]

To avoid rot, I wouldn't keep it in physical contact with the guitar itself.

Many woodwind players keep their instruments humidified by keeping a small, wet sponge in the case and wetting it as it dries out. (This can take anywhere from a day to a week, depending.)

 

[Markbnj]

To avoid rot, I wouldn't keep it in physical contact with the guitar itself.

Many woodwind players keep their instruments humidified by keeping a small, wet sponge in the case and wetting it as it dries out. (This can take anywhere from a day to a week, depending.)

I think that's the point of the rubber tube around the absorbent stuff, i.e. to keep it from actually wetting the wood. I can't really tell if the thing has dried out without opening it up, so I guess I'll give it a couple of days more then check it. The humidifier came with a humidity-sensitive cardboard strip that I can use to test it.

 

[dave_the_nerd]

I think that's the point of the rubber tube around the absorbent stuff, i.e. to keep it from actually wetting the wood. I can't really tell if the thing has dried out without opening it up, so I guess I'll give it a couple of days more then check it. The humidifier came with a humidity-sensitive cardboard strip that I can use to test it.

Ah, makes sense. My guitar case has a storage space with a door, so I'd just throw a sponge in there. (Same as I did for years with my bassoon.)

 

[Markbnj]

Ah, makes sense. My guitar case has a storage space with a door, so I'd just throw a sponge in there. (Same as I did for years with my bassoon.)

Yeah I have the same space in mine, but I keep a set of strings, capo, strap, and a little box with picks in there. Anyway, for re-humidifying a dried-out instrument in the body is supposed to work best. We'll see.

 

[Madwand1]

Oasis makes instrument humidifiers that deflate as they empty, showing you when you have to refill them.

http://oasishumidifiers.com/plus.html
http://oasishumidifiers.com/original.html

As others have said, I'd try to aim for longer-term stable humidity instead of massive swings. Hygrometers can be pretty cheap and despite being off by say 10% can give you useful information.

 

[squirrel dog]

I keep a sponge in a baggy that has holes in it placed in the case . Re wet every week or so . Guild D25.

 

[Markbnj]

As others have said, I'd try to aim for longer-term stable humidity instead of massive swings. Hygrometers can be pretty cheap and despite being off by say 10% can give you useful information.

Yeah, this unit I purchased is supposed to release the moisture at an optimum rate. We'll see. I can't do much about the ambient environment, so do you guys think that just keeping this thing moist and in the body during storage will do the trick? I'm not sure how I would use a hygrometer, since once the case is open and the soundhole plug removed the humidity in the body will probably be sliding towards the ambient level.

 

[lxskllr]

so do you guys think that just keeping this thing moist and in the body during storage will do the trick? I'm not sure how I would use a hygrometer, since once the case is open and the soundhole plug removed the humidity in the body will probably be sliding towards the ambient level.

I think so. For the hygrometer, it doesn't change instantly. You'll have a good idea what the humidity is by opening the case and looking. Humidity will drop due to the case being open, but will increase when closed. You're in PA or NJ, right? I'm a little surprised it's getting that dry there. Look into changing your storage location also. A cool dark place is best, but at least keep it away from heat registers.

 

[Markbnj]

You're in PA or NJ, right? I'm a little surprised it's getting that dry there. Look into changing your storage location also. A cool dark place is best, but at least keep it away from heat registers.

Yeah, NJ. Air conditioning all summer, and then the baseboard registers all the way around my small office in the winter. I think you're right, maybe I should just store it in the basement. I like to have it at hand because I get these urges to play something during the day, and if I have to walk downstairs for it then it won't happen .

 

[Scarpozzi]

Get one of these: http://www.amazon.com/Analog-Hygrome...=humidor+gauge

Throw it in the case and shut the lid. Leave it overnight and see what the humidity levels are....then add your sponge and re-check. You probably want it to stay around 50-55% humidity for a few weeks to rehydrate the wood. Anything higher than 50% prolonged will eventually promote mold growth or rot. (not necessarily cause it...just present proper conditions for it)

Edit: One more thing that helps is lemon oil. You can buy it in the furniture polish section of most stores. The most common point for cracking is the bridge and fretboard. I usually apply it every few months to my guitars when I change the strings.

 

[Markbnj]

Get one of these: http://www.amazon.com/Analog-Hygrome...=humidor+gauge

Throw it in the case and shut the lid. Leave it overnight and see what the humidity levels are....then add your sponge and re-check. You probably want it to stay around 50-55% humidity for a few weeks to rehydrate the wood. Anything higher than 50% prolonged will eventually promote mold growth or rot. (not necessarily cause it...just present proper conditions for it)

Edit: One more thing that helps is lemon oil. You can buy it in the furniture polish section of most stores. The most common point for cracking is the bridge and fretboard. I usually apply it every few months to my guitars when I change the strings.

Thanks for the tips. I've been using lemon oil on the fretboard, bridge and top whenever I restring for quite awhile now. I'll take your advice on the hygrometer.

 

[Markbnj]

Well, after a couple of days with the humidifier and getting the case to around 60-70% pretty consistently, I didn't really see any improvement in the top cracks or the bridge lift, both of which had been reported to be improved by humidity conditioning in some cases I've read about online. I do think the timbre improved somewhat. I'm going to take it over to a former Martin luthier in Pennsylvania and see what can be done about the top and action. It's a 40 year-old Martin, I figure it's worth some investment.

 

[bradley]

I ruined an expensive solid-body beautiful mahogany guitar simply by leaving it in a humid room for a month. The action and intonation on the guitar was never the same again, even after adjusting the truss rod. Wish I had this thread to read back then.

 

[Markbnj]

Took my instrument over to Finnochio Guitar Works in Easton, PA this afternoon. Frank Finnochio is an ex master luthier at Martin, and now repairs and reconditions guitars, and builds his own, out of one of the coolest little shops I've been in. He inspected the guitar and then walked me through a number of issues I hadn't noticed. In addition to the cracked top, there is a serious crack alongside the neck, the neck has actually moved closer to the bridge, interior braces (but not the X brace, thankfully) are detaching from the top, the nut is wrong, and the pickguard was replaced with the wrong pickguard years ago (and is now coming off).

So he is going to fix the top, reset the neck, replace the frets, fix the bridge and nut, and replace the pickguard with an original black D18 pickguard. Will take six weeks and a thousand bucks, but it's cheaper than a new Martin, and will sound better too. I'll post picks when I get her back. Meanwhile I'll be stealing my daughter's beater that she never plays.