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Interesting point about limitations of room humidifiers.


EuroAussie

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I just returned from my luthier who installed a guitar strap button to my SJ.

 

He gave it a quick once over and asked if Ive been humidifying the guitar ?

 

I said I have a room humidifier which has been working around the clock, with the humidity between 35-38% level, which is a bit below the recommnded 45%.

 

He commented that you have to be careful with room humidifiers because its crucial the humidifcation needs to suitably enter the soundhole to have effect, and with room humidifiers this will not always happen as its not a direct input into the soundhole, especially when thyre running below the 45% 'benchmark'.

 

He then pointed to the top of my SJ and made the comment it is too flat and the natural slight bow has flattened. Its ok for now but if it continued like this it could be a problem and recommend i put it in its case for a couple of days with a soundhole humidifier.

 

Luckily im away for 3 days on a business trip and will do exactly that so hopefully the moisture content will return to an appropriate level.

 

Just wanted to share that with you, i thought it was a good point.

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A good post . . . as there are a few members that use room/house humidification.

 

I humidify in the case, using a soundhole humidifier in the soundhole or just laying in the case with the guitar, depending on what the hygrometer in the soundhole is reading.

 

Not a typo. B)

 

 

 

 

<edit> In the post below, Hogeye makes a good point about dripping soundhole humidifiers. I use Oasis - no holes.

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Bob Taylor has done some very interesting research on humidifiers. It seems that humidity likes to equalize itself so if you open a door to a humidified room and the outside is not humidified the moisture will leave your room at the speed of sound until both rooms are equal. Then your humidifier will try to humidify both rooms until you close the door. It seems that it is more effective to humidify the guitar by using a soundhole humidifier. Cheaper too.

 

It's very important not to let the humidifier drip into the body cavity as the moisture will migrate thru the wood and damage the lacquer. If you use one of the long rubber tubes it is best to store your guitar standing up with the tube inside hanging vertical. If you lay the guitar on it's side the tube can and will touch the side of the guitar and the moisture will get into the wood it touches. Most of the tube humidifiers have ventilated holes the length of the tube. There is a 1 inch portion of the tube that has no holes at the bottom. When you charge the humidifier you should wring all the moisture out of the ventilated part of the tube and leave the closed part of the tube damp. The moisture will work it's way up the tube and out of the holes and gravity will keep the moisture from dripping out of the bottom of the tube. It's important the tube is vertical in your guitar for this reason.

 

As we all know dried out guitars can be re-humidified but why take the chance?

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He commented that you have to be careful with room humidifiers because its crucial the humidifcation needs to suitably enter the soundhole to have effect, and with room humidifiers this will not always happen as its not a direct input into the soundhole, especially when thyre running below the 45% 'benchmark'.

 

 

I hope this tech's recommendation doesn't cause anyone to shoot their portable room humidifier directly into the soundhole of their guitar. That could lead to some serious over-humidification. While I'm sure the tech is giving good advice about the need for better humidification of the particular guitar, the advice about entering the soundhole seems a bit odd. Because humidity in the air distributes itself throughout an area (Or "equalizes itself", as Hogeye put it), the humidity of the air inside a guitar on a stand in a room should be the same as that of the rest of the room. What's to stop the air inside the guitar from reaching the same humidity level? If the humidity in the room is too low, then the use of a separate humidity device is useful, but that's because the humidifier is not producing adequate relative humidity to do the job, not because there is enough humidity but it is somehow not getting into the sound hole. If the guitar lives in its case, the humidity in the case is important, although if both are regularly in an area with constant humidity, they too will equalize to the rest of the room unless there is some specific condition leading them to be different. The point, I think, is not what particular method of humidifying is used as it is that the measurement of the humidity level needs to be appropriate to the location of the guitar and the level needs to be sufficient where the guitar is. I humidify with a whole house humidifier attached to our forced air furnace, and I monitor with a professional level humidistat where my guitars are stored. Guitars are happy, I'm happy--fewer sinus problems, less static electricity, fewer furniture joints need regluing. If others like to use soundhole humidifiers, that's good too, but I don't buy that it is a better solution, just a different one.

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I agree with Tom and I wonder if the tech was misunderstood. Certainly, if you have a dried out guitar in need of some re hydration, a soundhole humidifier will do the trick. Bob Taylor has some excellent videos on this. Putting a sound hole humidifier in the guitar (like two damp-its) and closing it up in its case until the dampits are dry then repeating until the guitar comes back to form is the only way I know of to remedy this situation. If you tried to re-hydrate the guitar using a room humidifier with the guitar on a stand, it would take weeks and weeks.

 

So perhaps he was talking about the process of getting a guitar back to its proper humidity level (~45% RH). I know I've had my guitars on stands and wall hangers for years with a room humidifier and no signs of problems.

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I have just recently gone through a problem with humidity. I am using a room humidifer but the problem I have found is that the room humidifer's reading is not exactly correct and may give a false reading as to the amount of moisture in the room or near your guitar. It also records a samply usually close to the humidifer and not exactly where your guitar is. I have now purchased another hydrometer that I keep next to the guitars( don't want the humidfier blowing the moist air directly in them) and I have set my humidfier according to that one. some expiermenting has seemed to have gotten me to a point where I vary from 41% tp 47% with the door to the room open. Now I don't know how exact the hydrometer is but it is made by Planet Wave and seems to be a good one. I would think a scienceist would laugh at it but I think is should be in the ballpark to be useable. My guitar has improved in sound and all seems good with it. It is new and the shop where I got it had a lack of moisture problem they are working on and it was a bit dry. As far as the sound hole humidfier in the guitar case, wouldn't this raise the question "Why do they sell case humidfiers that just sit in the case ?". Aynway, I have been a member of this forum for as long at it took me to write this and I already got my 2 cents in. Must go out and interduce myself now in the introduction section. Thanks for the chance to contribute.

 

B00

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Howdy B00! My in home humidty during winter here in the Wilderness, otherside of the river from Cincinnati, does not get low at all with natural Duke gas. House is tight, so I don't push the issue. Seems like it can easily become a forum obsession to me. Widespread periodic use of in casers has always seemed sufficient.

 

Steve

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This is exactly what he was referring to. That a room humidifier which needs to cover a large room may not spread the moisture evenly across the room, and its a large room with stairs going to the loft upstairs.

 

If the reading near the humidifier might be 40% it might only be aroun 35% where the guitar is placed, about 3metres from humidifier.

 

By putting the guitar in the case and placing a soundhole or case humidifier you will ensure the guitar gets its moisture 'hit' 100%.

 

Anyway, this weekend the house heating stopped and the room humidifier went to 50% and i could definitely feel an improvement in the tone of all the guitars. Not as dry, much more robust and warmer tone.

 

 

I have just recently gone through a problem with humidity. I am using a room humidifer but the problem I have found is that the room humidifer's reading is not exactly correct and may give a false reading as to the amount of moisture in the room or near your guitar. It also records a samply usually close to the humidifer and not exactly where your guitar is. I have now purchased another hydrometer that I keep next to the guitars( don't want the humidfier blowing the moist air directly in them) and I have set my humidfier according to that one. some expiermenting has seemed to have gotten me to a point where I vary from 41% tp 47% with the door to the room open. Now I don't know how exact the hydrometer is but it is made by Planet Wave and seems to be a good one. I would think a scienceist would laugh at it but I think is should be in the ballpark to be useable. My guitar has improved in sound and all seems good with it. It is new and the shop where I got it had a lack of moisture problem they are working on and it was a bit dry. As far as the sound hole humidfier in the guitar case, wouldn't this raise the question "Why do they sell case humidfiers that just sit in the case ?". Aynway, I have been a member of this forum for as long at it took me to write this and I already got my 2 cents in. Must go out and interduce myself now in the introduction section. Thanks for the chance to contribute.

 

B00

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I don't buy it. Room humidifiers work fine as long as they are the right size for the room, and the humidity will average itself out across the room over time. Sure it will be higher right by the outlet of the humidifier but it evens out as much as a thermostat evens out temperature. As for playing "catch up" - getting a dried out instrument re-humidified- they work fine for that too and can achieve the desired effect in as short a time as any but drastic measures.

I have a 1917 Gibson A4 mandolin- beautiful carved top oval hole instrument that reacts to humidity in very obvious ways - the top goes up and down enough to change the pitch of the 8 strings by about a half tone. If I let my room humidifier run out of water and the humidity in winter drops to 30rh or so the top sinks, the action goes low, and I get buzzes; but before that the tuning goes flat. Just a little drop of the bridge and it goes flat. I could tune up to pitch ,or I could add water to the humidifier and let it run for a few hours. The top comes back up to it's happy place where it lives when the humidity- or moisture content in the mandolin- is is right 45%rh or so. When the top is back up in place the instrument goes right back to concert pitch and little tuning is necessary.

It takes maybe 24 hours of travel and playing in bars etc. to dry it out and have it go flat. Then, if I am not going to be home I use a sponge or two in the case. Otherwise it goes back into the room with the humidifier and recovers quickly. It has been like this for the 15 years I've owned it, probably been doing it for 90 years and it sounds great and plays wonderfully. I think the flexing of the top may be one of the things that makes it such a great mandolin.

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You just answered my point yourself. 'They are fine as long as they are the right size for the room'. This is a large humidifier but my room is also very large, two storied that goes into the kitchen.

 

In this case this humidifier is not large enoght to cover the space adaquately and thats why the RH has been around 35-38% and possibly less in parts of the room.

 

I buy it and the a case humidifier will be going into my Gibbys.

 

I don't buy it. Room humidifiers work fine as long as they are the right size for the room, and the humidity will average itself out across the room over time. Sure it will be higher right by the outlet of the humidifier but it evens out as much as a thermostat evens out temperature. As for playing "catch up" - getting a dried out instrument re-humidified- they work fine for that too and can achieve the desired effect in as short a time as any but drastic measures.

I have a 1917 Gibson A4 mandolin- beautiful carved top oval hole instrument that reacts to humidity in very obvious ways - the top goes up and down enough to change the pitch of the 8 strings by about a half tone. If I let my room humidifier run out of water and the humidity in winter drops to 30rh or so the top sinks, the action goes low, and I get buzzes; but before that the tuning goes flat. Just a little drop of the bridge and it goes flat. I could tune up to pitch ,or I could add water to the humidifier and let it run for a few hours. The top comes back up to it's happy place where it lives when the humidity- or moisture content in the mandolin- is is right 45%rh or so. When the top is back up in place the instrument goes right back to concert pitch and little tuning is necessary.

It takes maybe 24 hours of travel and playing in bars etc. to dry it out and have it go flat. Then, if I am not going to be home I use a sponge or two in the case. Otherwise it goes back into the room with the humidifier and recovers quickly. It has been like this for the 15 years I've owned it, probably been doing it for 90 years and it sounds great and plays wonderfully. I think the flexing of the top may be one of the things that makes it such a great mandolin.

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Thanks fot all the welcomes, \Glad to be here. I am going through this problem with the humidity now, I think I have solved my problem. The room humidifier does work but it's reading may be off, mine is. With an independent hydremeter I was able to get control of the humidifier and use a slow continues setting that suited my room. Fair size room with 10ft high ceilings. I can leave the room door open and the humidity varies between 42%-47%, no big deal. Yes, eventually the whole room falls in that range. I just moved the Plant Wave Hydrometer around and left it in various places. If you have a big room, try two room humidifiers if the one is not right. Just get something to check your room. I have a feeling about what I want with my guitars. I like to have them near for when I have a few minutes to fool around I just have to pick them up , the other thing I think we all share is that your guitar is a thing of beauty and you like to see it, gives you that warm feeling. My next problem is that summer is coming and too much humidity, gotta work on that but as mentioned, nothing wrong with perodic storage in the case, but only if I have to.

 

B00

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One point to take away from this is that the humidity will average out. The humidifier outlet will be high but anywhere away from that the air circulation will balance things out and the various rules of physics will take over. This goes for inside the guitar too, and for inside the case. All the case will do is slow down the changes in whatever direction- wetter or drier- and only for a few hours.

 

B00 I wouldn't worry much about high humidity in Halifax. It's not hot enough there on a consistent basis to cause damage to a guitar from gaining too much moisture. I tried a week of Summer in NC 2 years ago visiting my son and going to Mt Airy. It was 95-100 every day and 90+ humidity. Too much for my northern blood. I guess you can get used to it but I was glad to leave. Guitars- I don't think they get used to it. They need dessicant help.

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In the last three days spring hit in Prague with temperatures up to 25c for the weekend. The house heating went off, and the humidifier finally started winning the battle. The RH went up to 49% for three days and must say there was huge difference in tone. All my guitars just came alive with amazing sustain and deep, rich tone. The CW was just reborn.

 

Anyway, point is that these guitars really react to even small changes in humidity, its a timely reminder how important it is and the effect on tone it produces.

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It just so happens that Spring is on the way and a sure sign of it is that even the snow that is falling rigt now is wet. Soon we will be getting clear beautiful rain, no white in it. Time to break out the shorts.

 

B00

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One part of this that we are missing is the term "Relative Humidity"

 

Basically warm air can hold more moisture and cold air holds less. Relative Humidity is a way of talking about humidity which takes temperature into some context, but it is not Absolute Humidity.

 

Definition: A measure of the amount of water in air divided by the amount of water that the air could hold, expressed as 100 x P/P0, where P is the pressure of the water vapor in the air and P0 is the equilibrium vapor pressure of water at the same temperature.

 

Example: A relative humidity of 95% indicates that there is 95/100ths as much water in the air as that air is capable of holding at that temperature.

 

So I believe an easier way to express this is that 45% RH in the winter with temps down in the 60's in the house means less water in the air than 45% RH in the summer with temps up in the 70's or low 80's in the house. So even if we keep our RH in the house absolutely constant year round, there is less absolute humidity during the winter months.

 

So if the OP is holding his RH at say 38% in the winter...that may end up being a bit low during the winter but fine in the warmer summer.

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