So how close to 40-55% humidity should I be?

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Andrew Fryer
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Re: So how close to 40-55% humidity should I be?

Post by Andrew Fryer » Sun Jan 21, 2018 8:02 pm

No, RH in the UK goes a lot below 70%
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Rasputin
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Re: So how close to 40-55% humidity should I be?

Post by Rasputin » Sun Jan 21, 2018 8:06 pm

https://www.currentresults.com/Weather/ ... annual.php

It's worth bearing in mind that these are outdoor figures. Indoor figures would be lower because of heating, but I don't know how much lower.

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Michael.N.
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Re: So how close to 40-55% humidity should I be?

Post by Michael.N. » Sun Jan 21, 2018 8:26 pm

Rasputin wrote:
Sun Jan 21, 2018 7:30 pm
Michael.N. wrote:
Sun Jan 21, 2018 5:56 pm
You need a fairly accurate hygrometer. You need to know the RH that your guitar was constructed at. You need to keep your guitar within a reasonable figure of that RH...
It looks as though outdoor RH varies between about 70% and 90% in the UK, and yet people from warmer climates are saying they see about 60% as a maximum. Could this mean that it is absolute humidity that really matters? I haven't thought about the physics of it - at first blush it seems plausible that RH would equalise even if it meant large disparities in AH, the way temperature equalises even if it means large disparities in heat - but maybe it is more complicated than that.
Forget RH measurements outdoors. I measure/monitor room and workshop (indoor RH) on a daily basis. Lowest I've seen it is 25% RH (cold winter) and the highest was just over 80% RH in summer. It can be anywhere between those two figures though often it stays in the 50 to 65% range - unless I switch my dehumidifier on to control and bring it down. You can also lower it by raising the temperature although it's much easier to control things in a relatively air tight box. Makers of wooden musical instruments know this as a conditioning cabinet.
The smaller the room (space) and the more air tight it is the easier it is to control RH level.
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Rasputin
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Re: So how close to 40-55% humidity should I be?

Post by Rasputin » Sun Jan 21, 2018 9:07 pm

Hmmm, better order a hygrometer then.

soufiej
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Re: So how close to 40-55% humidity should I be?

Post by soufiej » Sun Jan 21, 2018 11:38 pm

"No! That's nonsense. 'You are the best measurement tool that you can have' ? I mean seriously, what sort of advice is that? You wait until the crack appears and then you take action? That's what you seem to be suggesting."


It's not what I'm suggesting. Read the entire post again.

My point is, a hygrometer is reading the wrong value and many people on guitar forums spend literally several hundred dollars on a sling hygrometer to reach +/- 1% or better accuracy. Even if your $10 meter is off by 5%, it's still reading the wrong value. Since you cannot accurately and easily measure the moisture content of the various wood(s) in your instruments, we rely on something that has little value to the actual condition of a guitar. 40-60% R.H. is a broad range, there's not much to worry about if the meter reads slightly above or below that range unless the measurement stays extremely low for weeks. Strive for consistency above all else. If the meter reads very low values for long periods of time and you can tell your guitars are beginning to loose moisture, don't run the humidifier at full bore to raise the moisture content rapidly. Just like temperature, allow your guitars to adjust gradually.

Move the average hygrometer five feet in any direction and the reading will likely change. So, how many guitars you own would tell you how many hygrometers you should own - and you would still be looking at the wrong value.

Different woods absorb and release moisture at different rates. How does the meter adjust for that? It doesn't, so you shouldn't be all that concerned with any single meter reading.

IMO there's no point in having more than one moderately accurate meter. Read it often but don't get all that concerned with the lowest or highest reading, it's not the R.H. you want to know about. It was 14 degrees in Dallas Tuesday night and 15% R.H.. Two days ago the furnace was running almost constantly for 18 hours of the day. Today the outdoor temperature will hit the low 70's but the R.H will be as high as 89%. So I shut down the humidifiers this AM and probably won't run them for several days as the guitars need to loose a bit of moisture now. I really don't need a meter to tell me that much. Pay attention to your local weather report.


All I'm saying is pay attention to your guitars and not a meter. Don't live by a meter reading and don't spend a lot on a meter. Playing your guitar and paying attention to its appearance and its sound will go much further toward protecting your guitar that any meter can. You can tell better the condition of your guitars than any meter can manage. Don't wait for a crack to appear but, if that should happen due to very low humidity, most small cracks will heal themself once the wood rehydrates. If you're paying attention to your guitars, no cracks should start. Pay attention to your guitars, not a meter.

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Re: So how close to 40-55% humidity should I be?

Post by JohnB » Mon Jan 22, 2018 12:38 am

soufiej,

There is quite a bit to disagree with in that post.

"Small cracks will heal themselves"
Really? That most definitely wasn't the case with my Hermanos Conde '68 with Brazilian Rosewood back and sides! It might be the case that in certain circumstances the crack will close up somewhat, but it will not heal itself. There is also the possibility (perhaps likelihood?) that the crack will develop further, possibly over many years, until it reaches an internal brace.

The idea that a hygrometer that measures the ambient RH is not all that relevant because it doesn't measure the moisture content of the wood seems extremely questionable to me. If the guitar was built in an environment where the RH was, say, 40-50% the moisture content wood will have reached an equilibrium in that environment. We don't need to know the actual moisture content of the wood. Once the guitar is placed in an environment where the RH differs significantly from that in which it was built, especially if the RH is significantly lower, stresses will build up in the timber which can lead to cracks developing.

Interestingly, I remember Michael telling how he made a RH gauge from two sheets of wood glued with the grain an 90 degrees to each other. I seem to remember him saying that it reacted to changes in RH within 30 minutes. So guitars are also likely to be affected by similar changes in RH within hours, not days.

As for telling the condition of a guitar better than any hygrometer - well if you can do that, fine. But for lessor mortals like me that sounds like a high risk strategy, especially if one has in instrument costing hundreds or thousands of pounds/dollars.
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soufiej
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Re: So how close to 40-55% humidity should I be?

Post by soufiej » Mon Jan 22, 2018 2:45 am

"The idea that a hygrometer that measures the ambient RH is not all that relevant because it doesn't measure the moisture content of the wood seems extremely questionable to me."


That too is not what I have said. Did I not say, "IMO there's no point in having more than one moderately accurate meter"? Did I not add, "Read it often but don't get all that concerned with the lowest or highest reading, it's not the R.H. you want to know about"?

What is so difficult about comprehending my basic statements? Are you so sucked into the "guitar accessories" market so deeply that you have to chase every little item they tell you to buy?

Look, buy a hygrometer, just don't spend a lot on it. Look at your hygrometer from on occasion to as often as your OCD permits. Just don't think it is telling you what you need to actually know. Your guitar will do that. Oh, and stick your head out the window every now and again to see what the weather will be. Read a newspaper. Pay attention to the world around you.

Is that so difficult to comprehend?


"Small cracks will heal themselves"

"Really? That most definitely wasn't the case with my Hermanos Conde '68 with Brazilian Rosewood back and sides! It might be the case that in certain circumstances the crack will close up somewhat, but it will not heal itself."


You forgot my next statement, "If you're paying attention to your guitars, no cracks should start."


Sounds to me like you weren't paying attention. Why did your guitar crack? Did you buy a cheap meter and not pay attention to it? Did you buy an expensive meter and expect it to care for your guitars?

I don't know but you seem to be blaming me for something I had nothing to do with. Did you not pay attention to your own guitar? If you didn't, then you've just proven my point. If you did, then your guitar shouldn't have suffered from you not getting the idea woods respond to moisture and the lack of moisture. This is stuff you should have learned in grade school.

Did you not realize your guitar needs maintenance and that maintenance begins with you paying attention? Sorry, I can't be held responsible for someone who apparently doesn't understand how wood responds to moisture. If the crack progressed and you did nothing to stop its progression, what exactly were you paying attention to?

Wood contracts and wood expands. That's all I am saying. If you can't understand that and your instrument breaks to the point it is damaged, how am i to be held responsible for advice I did not give prior to the damage taking place? Physician, heal thyself.


"Interestingly, I remember Michael telling how he made a RH gauge from two sheets of wood glued with the grain an 90 degrees to each other. I seem to remember him saying that it reacted to changes in RH within 30 minutes. So guitars are also likely to be affected by similar changes in RH within hours, not days."


Pay attention to your guitar and not a meter - and not to two sheets of wood glued together - and you will learn just how rapidly your guitar needs attention. Is that not what I am promoting? Different woods react to moisture differently. Doesn't seem that mysterious to me.


"As for telling the condition of a guitar better than any hygrometer - well if you can do that, fine. But for lessor mortals like me that sounds like a high risk strategy, especially if one has in instrument costing hundreds or thousands of pounds/dollars."


A "risky strategy"? No more of a risk that depending on a meter that tells you nothing because it is reading the wrong value. Are you actually saying you cannot hear and feel the difference between your guitar being dry and being wet?

There's no magic to it. There's no risk once you begin paying attention.

Pay attention to your guitars. Stop depending on the meter.

What do you think players did before they could buy a hygrometer? All of this is like saying your dog got sick because the food you were feeding didn't warn you it could poison your dog. Pay attention to your pet. It's your responsibility.

The government tells you to turn on your automobile's headlights after sunset. I'm still in perpetual amazement people actually need to be told to do that! Pay attention! Indicate at least occasionally you didn't sleep though your entire educational experience.

Good grief! If you've invested in a decent guitar, what else would you do but play it, listen to it and be aware of when it changes?

This ain't rocket science, folks. Buy a meter and look at it. Realize it is not telling you what you need to know. You can better determine the condition of your guitar than can a meter that doesn't care what you own or how much money you spent.

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Re: So how close to 40-55% humidity should I be?

Post by Jeffrey Armbruster » Mon Jan 22, 2018 3:22 am

soulfiej: "The woods in your guitar retain moisture, lose moisture and then they take in moisture again. It's a continual process. That means on more humid days or under higher R.H. values the wood is seeking parity with the air."

And so I want to know about the RH in the air in my apartment (not outside). I find a hygrometer useful. I take appropriate action based on that--which in my case is simple. Humidipak goes into the body of the guitar, or not. The RH where I live is very benign.
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Michael.N.
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Re: So how close to 40-55% humidity should I be?

Post by Michael.N. » Mon Jan 22, 2018 8:19 am

Really. Just buy a hygrometer, a fairly accurate one. It DOES tell you what you need to know. If you are in the US buy the David Burgess one - he's a highly respected violin maker who obviously understands how wood reacts to RH. It's not expensive. Guitar woods are thin, they react to humidity changes relatively quickly. The wooden hygrometer indicator that John mentions is slower to react than a digital or hair hygrometer. It's probably nearer to what the guitar wood is experiencing. None of that matters, they are both good enough for our purposes. Use them as a traffic light signal. Assuming 50% RH construction, 50% is green, 40% is amber, 35% is red. You can move those amber and red figures down 5% but the risk increases slightly. Don't fuss about playing your guitar in a 30% RH environment for an hour or so. I can't guarantee it (no one can) but it's unlikely to suffer consequences providing you return it to a humidified case/cabinet. Certain woods and certain cuts of wood are much more susceptible to cracking than others, it's impossible to predict in any accurate way how the particular woods are going to react to humidity changes. The majority of woods may be able to take some humidity abuse but that doesn't mean to say that your guitar is one of the lucky ones.
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soufiej
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Re: So how close to 40-55% humidity should I be?

Post by soufiej » Mon Jan 22, 2018 3:16 pm

"And so I want to know about the RH in the air in my apartment (not outside). I find a hygrometer useful. I take appropriate action based on that--which in my case is simple. Humidipak goes into the body of the guitar, or not. The RH where I live is very benign."


Well, yes and no. If you are fortunate enough to actually live in a constant environment which is neither too wet nor too damp, you're lucky. So are your guitars.

Most of us aren't that lucky. As I noted, this week in Dallas we went from the low teens to the low '70's in temperatures in the course of five days. Temperature drives R.H. (both inside and out) and your HVAC system is only responding after the fact to those changes. The R.H. went from 15% to 89% in that same time. Knowing a bit about that in advance would have helped any guitar player plan to deal with their guitars IMO. Is it so radical to say "be pro-active"? Understanding the woods in your guitar are all expanding and contracting at different rates would help also. Knowing your AC will also dry out your guitar should help.

Paying attention to your guitars is the most important thing you can do because all the rest is too variable in some (most?) climates. Maybe it would help if I said think of your guitar as bread dough. Any bakers out there? The R.H. in the environment affects the amount of liquid you will add to your dough to reach a desired consistency. Yes, it's the inside R.H. that you are working in, but it is the outside R.H. that may drive the moisture content of your dough if you live in a volatile climate.

When it's dry or when it has been dry outdoors, you will feel the dough one way. When it's damp inside or been damp outside for a while, you will feel that too. Your mothers and your grandmothers knew that and they didn't need a meter to tell them. They did so by being knowledgeable and experienced. Be your own grandmother.

The same applies to your guitars. Pay attention to your guitars, they will tell you what you need to know.

Now, I do not advocate just setting the temperature in your oven by feel. No. Meters have their purpose, as long as they are measuring the correct value.




"Certain woods and certain cuts of wood are much more susceptible to cracking than others, it's impossible to predict in any accurate way how the particular woods are going to react to humidity changes."


I agree with that statement and note your guitar is made from several varieties of woods. Pay attention to your guitars, a meter does not know what they feel like or how they sound. Any meter, IMO, is no more than a brief one page outline to Moby Dick.

Remember, folks, the desired R.H. range for your instruments is spread across a 20% range and your guitar is not going to fall apart after a few hours - or even a few days - outside that range. Fortunately, that 20% range exists where most of us are comfortable when our homes are heated to approx. 68-72 degrees. How many more numbers do you need? I just can't help but be amazed at all the hysteria over this subject.
Last edited by soufiej on Mon Jan 22, 2018 3:29 pm, edited 2 times in total.

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Michael.N.
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Re: So how close to 40-55% humidity should I be?

Post by Michael.N. » Mon Jan 22, 2018 3:24 pm

Soufiej. I've been making guitars to close on 40 years. You really are writing some nonsense. I think I'll leave the thread and let others decide on what the best advice is.
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soufiej
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Re: So how close to 40-55% humidity should I be?

Post by soufiej » Mon Jan 22, 2018 3:30 pm

" ... let others decide on what the best advice is."


Good advice. We all get to decide how to treat our own guitars. A builder needs different advice than an owner.

I know I don't bake by strict measurements and neither should anyone else. People who do scare me.

soufiej
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Re: So how close to 40-55% humidity should I be?

Post by soufiej » Mon Jan 22, 2018 3:40 pm

This $30 meter is all you need IMO; http://www.burgessviolins.com/products.html Thanks to Michael for the suggestion.

Can you buy it for less? Yeah, most web sites sell it for about $10. Do you want your's already calibrated? Buy this one. Or, can you follow instructions and do it yourself? Then buy the cheaper version. It's all you need.
Last edited by soufiej on Mon Jan 22, 2018 3:41 pm, edited 1 time in total.

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prawnheed
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Re: So how close to 40-55% humidity should I be?

Post by prawnheed » Mon Jan 22, 2018 3:40 pm

Michael.N. wrote:
Mon Jan 22, 2018 8:19 am
Really. Just buy a hygrometer, a fairly accurate one. It DOES tell you what you need to know. ....
I agree.

astro64
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Re: So how close to 40-55% humidity should I be?

Post by astro64 » Mon Jan 22, 2018 3:49 pm

I agree, one hygrometer. Don't worry about outside humidity, worry about indoor RH in the places where your guitar is. I have many times compared digital and analog hygrometers since I keep a few around the house in different rooms (because it is not only guitars that don't like the low humidity we get in NM). Every comparison shows that, yes, they vary from one to the other, but the variations stay pretty much the same. So if one gives 40% and the other 35%, that will still be the case 5 years down the road. And if the first shows 50%, the 2nd will show 45%. Since the guitar only needs to be near 50+-10% without anything bad ever happening to it, any hygrometer that is within +-5% accuracy will do.

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