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Hello Listers:

I have a Martin HD27v guitar that I purchased new in 2002. About 1 month ago I decided to take the guitar out of its case and hang it up so I would be more apt to play it.

I have other instruments in the same room so I monitor humidity via a humidistat and humidifier. I am able to keep the humidity at 28 - 32 percent but cannot get the humidity above that in the winter months. Unfortunately, at one point, due to a problem with the humidifier, the humidity got down to 22%.

Two days ago, I noticed as light reflected off the top of the guitar ridges that coincided with the grain of the top. BTW I do keep direct sunlight out of this room. I ran my hand over the surface of the top and sure enough, it was no longer smooth as I could feel these ridges. The ends of the frets are not sharp and I am not getting any buzzing on the frets, so I am assuming that the fingerboard has not dried out and the top hasn't dished.

I called Martin and they said that my guitar was drying out -- that I needed 40-50 percent humidity in the room. If not I should keep the guitar in its case with a Dampit during the cold weather months. They also said that the ridges-effect on the top of the guitar would stay that way but that sound would probably not be affected.

So, I immediately put the guitar in its case with a Dampit. I also put a humidistat in the case with the guitar. I closed the case and fastened the latches. After 48 hours, I checked the humidity in the case and it was only 35% (same as the room humidity). So, I put a Dampit for a bass in the soundhole with the other Dampit and waited 24 hours. The humidity was still on 37%.

My questions:
* How do I get more moisture in the guitar? How do I get it at a consistent 40-50 percent?
* Is there something better than a Dampit that I should be using?
* I have other instruments that sit out all the time (mountain dulcimers, banjos, etc) and they do not seem to be affected by the 28 - 32 percent humidity. Are guitars particularly vulnerable to low humidity? Do guitars require a higher level of humidity than other instruments?

Thanks in advance for your input. I really don't want to do any other damamge to my guitar or other instruments.

Tom in Ohio

I am sure the pros will chime in here but I was just reading about this today. Check out the Taylor guitars site in the reference section. There are a few Tech Sheets on humidity and guitars. Some good info there. I have to run my humidifier on high constantly to keep it at 40-45 in the winter. Its a pain filling it up twice a day but I guess its the price I pay to keep the wood I paid for from being worthless

I second Hesh's thoughts about getting a good digital gage, I wondered about that when I read your post. I am able to keep my house at 45% with two freestanding humidifiers in the winter when I was in NY. Yep I had to fill them 3 times a day. But your guitars will thank you, all the other wood products will thank you and your sinuses will thank you. Get that humidity up... Oh yeh, your house will feel warmer in the winter too.

Hi Tom and welcome to the OLF, what Frank Hesh and Mike said, i'm the lucky one who has 45% RH all year round, your guitar wood was accustomed to 45% and yes, do get a humidifier to protect your instruments!

Good luck

Tom
I use ameritage cases which have a built in humidifier/dryer in them.
They also have a hygrometer and thermometer.... They are first rate
cases. Others here on the forum will agree.   They also sell the humidty
control system separately so you can retrofit other cases. My contact is
Nancy Worsford at Ameritage. nancyw@gwwcases.com
The retrofits were $33.15 each. $78 list
webpage
http://www.ameritage.com/details.php?sku=AME-
CTRL&cat=Accessories&line=Case_Accessory_Items&pname=Retrofi t_Hu
midity_Control_System

Andy

_________________
Andy Z.
http://www.lazydogguitars.com

any wood instrument will be affected by humidity changes. the larger the instrument the greater the affect will be. so guitars will be affected more than a mando or dulcimer; a bass or cello more than a guitar.

at the extreme end low humidity will cause the tops to split and to pull away from the sides.

as for you banjos, in the old days of calf or goatskin tops they would split or get so soggy they would plunk instead of ring. the modern plastic tops have made the banjo victims life far easier.

and it takes time to rehumidify the case/instrument. a good case is plywood and it will needs to be rehumidified as well before the air inside the case will read in the correct range, and it is the air which the hygrometer is measuring. it doesn't happen instantly.

Serge ... you have 45 RH year round ?? I take it thats in your house, somewhat sealed up, because there is no way that anywhere in Quebec its 45 per cent year round. Its way to cold and dry in the winter for it to be anywhere above 15-20 percent. And in the summer it gets to 70-80 (even 90 around her in TO) a lot of days.

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Tony, i dunno much about RH in a normal house, all i know is that my shop has a concrete floor and i'm surrounded by 4 cement blocks walls , no windows, i had bought a RH indicator after Christmas and the RH stands at 45 most of the time, it will lower to 41-42 if i move a lot of stuff in there like when i did my shop makeover. The type of soil underneath our building is an old swamp that was probably filled with material.

My RH device could be giving false readings though, i would have to buy a second one and compare the 2 readings to see if one will tell on the other. What i've noticed is the temperature in there is a little higher in summer time but i glued my guitar during that season and have had no problems, a big fan helped to keep the place liveable.

For the shop being sealed, well, maybe, i have no windows, just a door that i keep shut most of the time because the public is not allowed in due to the archives of the company being stored in there.

Honestly, i really don't know if the RH IS 45% all year round, it feels like it's the same climate in there all year. I sure will check the readings more closely this spring and coming summer though.

I supply all my guitars with a Planet Waves soundhole humidifier and a digital Hygrometer. In my house (an old house over 3000 Sq. ft and another 1500 sq. ft basement) there is no way I can maintain the humidifity properly when it is -40 out. even with a built in humidifier on my furnace it will sometimes drop to under 30%. The soundhole humidifiers and guitars in their cases makes the difference.

Yeah, my apologies guys, i think i assumed it stays at 45% all year round, of course it is warmer in there in summer time and will sure have a fan to help for air circulation. I'll try not to talk through my hat next time Again, it will be interesting to watch what the RH indicator will show in the coming weeks and months, i should also take notes of the variations when seasons change though it stayed constant at 45% all winter long.

Here in Northern Ontario, if I don't control the humidity, it will drop below 20% in the winter and get up as high as 90% in the summer. I've also discovered it's good to have a couple of Hygrometers as occationally you get one that isn't accuarate and even if it was accurate after a few years they can go on you.

Just came back from the shop, the RH was dead on 45% but i will do as you say Richard and get me a second hygrometer and compare the results, it did not feel dry or humid, it was just comfortable.

Serge, I wouldn't be surprised if you're right on, in a basement in the winter. But I would bet that the humidity will be much higher in the summer. Most basements are naturally damp. Of course, since your shop is located in a commercial complex, the overall temp/humidity might not be what home/shop humidity levels are.

Ron

_________________
OLD MAN formerly (and formally) known as:

Ron Wisdom

Somewhere in the middle of Arkansas......

Thanks Ron, i felt a little stupid assuming it was like this when in fact i've just been using a hygrometer for the last couple of months, my foot is in my mouth for it! .But i just can't wait to see what it's like in the summer time with the same environment and climate unless we'd have a very different kind of summer this year, last year was very humid but with the big fan in that small shop, it made it really comfortable through last summer. i'll be looking for a second hygrometer of better quality to check on the cheapo one i got in the shop now!

ThanksSerge Poirier38809.5218055556

Serge, I've had really good success with the Hygrometers I buy at Home Hardware. Don't listen too much to us a sYou may be right about the humidity staying constant. It really depends on Location. Near The St. Lawrence you probably have more constant humidity, Up where I am it's crazy but as they say , Location, Location, Location.

Cool Richard and thanks for the home hardware tip, me and my wife will be heading to Longlac in the middle of june to see the Family, if you happen to drive by, stop and say Hi!

LongLac wow, Just there a few weeks ago for my son's hockey tournament. Around here this is the time of year humidity can't decide what to do, After months of using the humidifier last week I had to dehumidify all week and today I'm back to the humidifier. arvey38809.9346990741

Last time we went there, i think it was a 17 hours trip in my old 91 pontiac 6000. I think i slept for 2 days when i finally got there!

Again tonight it still holds steady at 45, don't know if you can see my hygrometer in this pic, right above the scroll saw, i bought it at Canadian Tire or Wally World for a couple of bucks.I definitely have to buy a better second one!

I use a pair of hygrometers, and if they agree with each other within 5 degrees (accuracy ain't better than +/- 2.5 degrees, methinks), I'm happy. My relative humidity is pretty stable, indoors, close enough to perfect that I can adjust by merely opening a window or turning on the heater a little 10 months out of the year. The other two, I just stick to building less finicky electrics ;-)

Hi Mattia, been a while since i last saw one of your post, good to see ya back bud!

[QUOTE=Serge Poirier] Hi Mattia, been a while since i last saw one of your post, good to see ya back bud! [/QUOTE]

I ain't been that quiet, have I?

Mostly, I'm no longer faffing about at home translating; right now I'm at the hospital in a computer lab selecting angiograms for analysis/analyzing them (research internship) until I get to FINALLY start my clinical rotations, and after 2 years of those I'm a proper doctor. I'll be an MSc with a bit of paper and all that come April 25th, though

Downside: won't be building or perusing forums quite so much...

Yeah, you must be drowned in work over your head with that internship, i hope you can at least find some time to relax and play guitar once in a while!

Take good care Mattia!

Tom,
I agree with all the comments about humidity control, but one of the
things you mentioned was the grain lines on the guitar top were showing
up as ridges. That can also be partly due to the finish shrinking over time.
In fact, I've yet to see any instrument with a little age on it where this
hasn't happened.
Craig

[QUOTE=FrankC] I am sure the pros will chime in here but I was just reading about this today. Check out the Taylor guitars site in the reference section. There are a few Tech Sheets on humidity and guitars. Some good info there. I have to run my humidifier on high constantly to keep it at 40-45 in the winter. Its a pain filling it up twice a day but I guess its the price I pay to keep the wood I paid for from being worthless[/QUOTE]

Ah, Frank, are you talking about guitars or just tonewood? There is certainly no need to keep tonewood stored at any kind of constant humidity. In fact, that is the thing NOT to do. Wood ages by passing through the seasonal cycles of moisture and temperature. That is what has made the 50 year old tonewood a thing to savor. Storing wood at constant conditions eliminates this process. And with more of our wood being kiln dried, this is even more important now than it used to be.

Yes, when you are going to build with some wood, bring it into the shop and let it stabilize for a few weeks or so under your building conditions. But, in the meantime, let it live

Grant