Humidity (again!)
 

Hello, everybody. New forum subscriber here, with a query that I hope someone can finally nail for me, because I'm very confused.

I just bought myself a guitar. It's my first brand new one, so I guess I am paying more attention to the small detail than previously. There was a manufacturer's leaflet in the case with the instrument going into great detail about the horrors of over and under humidity, which succeeded in putting the fear of God into me. So I got online and bought a digi-hygrometer and read up masses of threads on the web. My confusion is this: the maker says the guitar was made at a temperature of 22 deg C and a humidity of 45% relative to that temperature. The folk posting in forums seem to pay a lot of attention to achieving an RH figure of 45 - 50% , but nobody says much about the temperature at which that value is obtained. The hygrometer is showing that my "guitar corner" reads a nice 44 - 49% RH value range, but the temperature there is generally about 12 - 15 deg C. I have calculated that to match the absolute humidity level that corresponds to an RH of 45 @ 22deg C, I should be aiming for an RH of about 80% at my room temperature of 12 C! Two problems : 1) that seems rather high, and 2) I haven't a clue how I would get the humidity up to that level. I could of course switch to keeping the guitar in its case (seems a shame) and using a Humidipak setup. But the case would still be in the same low temperature, and I doubt that the Humidipak is designed to raise the RH up to anything above 45 - 50%, whatever the temperature is. I certainly can't imagine it will get up to 80%.

Sorry to be long-winded about this. Have I misunderstood the whole humidity issue, or do I have to move to a warmer continent if I want to own a guitar? Any advice, anyone ...?
Regards
Baffled

That is why it is "relative" humidity. And you want 45% to 50% regardless of temperature. Why "you" want specific humidity is on you. If that is what is wanted that is what would of been used.;)

That said let's get onto temperature. 12c is a bit cool on temperature alone I would say. I know they say 72F to 75F and fine that is ideal. But 65F to 85F would not concern me remembering to keep RH @45%-50%. And I wouldn't freak if higher but where I am those temps are usually unacceptably high in RH.

It is the RH that is critical not the specific humidity because RH gives you an indication of "vapor pressure" specific humidity alone tells you nothing about vapor pressure. Just is in real life you might notice that when hot and humid you feel hot and muggy. Evaporation cools that is why you sweat. High RH reduces evaporation so in addition to not evaporating and cooling you get wet on your skin. To low your skin gets dry. Vapor pressure and reaching a point of equilibrium. Your guitar does not produce heat and does not sweat but it does hold moisture you don't want too much or too little. It will absorb and dry.

To go over board you could measure the actual RH of the wood usually 7% to 10% depending on species. But the poking of holes might be a problem.

So do not worry SH just RH and I would try and get above 12c.:)

Wow--12-15 C is 53-59 F. That's awfully cool for living in...makes for slow fingers, I would imagine. My man cave is in the basement, but I bottom out at 60 F in the winter...

Short answer is, as others have stated, pay no attention to either absolute (specific) humidity or the temperature at which the maker made the instrument. They are irrelevant to you, the owner.

Keep the instrument around 45% relative humidity. Do not subject the instrument to large, sudden changes in temperature, which is hard on finishes often causing them to craze (crack).

Care for fine wooden guitars is actually very simple and straight-forward, despite much of what is said about it.

Welcome to the forum !
Now turn the heating up, before anyone says anything derogatory about Welsh folk being a bit too careful with money.... :lol:

I use an Oasis Plus sound hole humidifier and some of LJ's sponge humidifiers in the case as well. So far so good.

Humidity (again!)
 

Thanks for your posts, everyone. It's a relief to know that it's not as complicated as I feared.

(Thanks also for your concerns over my cold living conditions. I can confirm 53F - 59F is not great, but I have a nice line in woolly pullovers!)

Cheers for now
Baffled

Are those feedback buster looking Kyser things alright for my guitar in the living room? I've got a humidifier in my music room so the ones in there are good to go. Just need to get a bigger one. It's like a half gallon humidifier and i have to refill it too often.

If the rh is low in your room, a Keyser soundhole humidifier will not properly keep your instrument humidified. Nor will an Oasis soundhole, or any other humidifier.

Hi Baffled,

I'm in Sussex, and keep a watchful eye on the humidity around my fine American built guitars which I keep in cases most of the time.

Here in the UK we don't really have the extremes of humidity that the Americas, and some other regions have.

If your house is well insulated and you have central heating in winter, your inside humidity might drop to maybe 35% with 90% outside. If so, then keep instruments mostly in cases, and maybe buy a soap dish with some slightly damp sponge in it into the case - or even half an apple - note: nothing moist/wet should actually come into contact with the guitar.

During the summer, we have little to be concerned about.

You may notice that in high humidity, your guitar may sound "tubby" and in low humidity , a little harsher. Action may also vary a little.

Don't worry,
enjoy your guitar.