Humidity and ukuleles?

Dan Gleibitz · Aug 21, 2016

Note: I did search for an answer. Got a lot of threads but no answers.

I'm a bit curious about what people are aiming for when they try to control humidity around their ukuleles. Is the only important thing the _relative humidity_ (expressed as a %)? Or do you also control temperature? What about absolute humidity?

As I understand it, relative humidity relates to the amount of water in the air as a percentage of carrying capacity. Warm air can carry far more water than cool air. So the same amount of water in the air, at a higher temperature, will report a lower RH. If we wanted to control the quantity of water in the air, we'd need to control both temperature and RH.

Or am I overthinking things? Is the critical point simply to prevent the ukulele from drying out too much? Lower RH increases evaporation, as the air sucks up water (and sweat, which is why warm air can feel drier even when it has higher water content). We don't want the air to suck moisture out of the ukulele?

What about if we do humidify, and then temperature varies? Suppose I put a damp sponge in a plastic bottle in my uke case. The temperature rises to a delightful 27 C during the day. Relative humidity drops. Inside the case, the humidifier compensates by allowing the air to absorb its moisture. Great! The ukulele isn't getting dried out. But then the night gets cool, down to 10 C. Won't the ukulele then be subject to very damp air, perhaps even condensation?

I'm just curious as to how this all works.

stevejfc · Aug 21, 2016

A relative humidity in the 45 -55% range in the case (or if your uke is outside of the case for an extended period) is ideal. I wouldn't be concerned with temp unless it is to extremes hot or cold or changes dramatically over short periods of time

Mivo · Aug 21, 2016

I'm a bit more concerned with mold inside the case than I am with dryness. But low humidity isn't a concern where I live. Outside of very cold winter days, the humidity inside the house is always between 45% and 70%, mostly around 55%. In the winter I have seen it drop to the low 30s, at which point I placed a large bowl of water in the room where I keep and play most of my ukuleles. I do have a couple of humidifiers for cases, if it becomes necessary, but I'm not using them.

I think you are overthinking it, yes, though it depends on where you live and where you take your ukes. There are places and situations where you really do have to be careful, but for the most part I think we are probably all fretting too much over this.

Rllink · Aug 22, 2016

I'm quite sure that your ukulele has no idea what the humidity is. Just don't let it dry out.

Dan Gleibitz · Aug 22, 2016

Thanks all for the advice. Where I live the it can get to 44 degrees C (111F) and <7% RH in summer and as low as -4 degrees (25F) in winter. But these are extremes, and outside, and generally for brief periods. A 2mm diameter unfinished stick of wood will take an hour or two to dry out, by which time the extremes have probably abated.

I'm probably not going to bother doing anything for the sake of my cheapo ukes. I have much more expensive guitars that are left to fend for themselves.

The science behind it interests me though because I have an unlimited supply of Acacia melanoxylon at hand, some large enough for quarter-sawn 1 piece jumbo guitar tops!. I'm planning to mill some to try my hand at building ukuleles. Understanding the wood might help prevent me from making mistakes that lead to firewood (although I'm told Blackwood makes pretty good firewood).

AndieZ · Aug 22, 2016

I'm trying to understand this a little better becuase most of the above is a bit vague and or ambiguous to my mind. I live in a tropical climate where dryness isn't an issue, however i will be travelling over the next year and i will have other issues. Dryness will probably come up.

So this is my understanding so far. The big problem is rapid changes in humidity. If something dries out quickly, its likely to cause cracking. If the uke gets wet, and i mean wet, the wood will swell up and can warp. (i've seen that with my sister's wood floor before it got sealed.

So the aim is to minimise the extremes and also the speed of humidity change. When i bought mine the salesman just told me to keep it covered. This will help slow down any humidity changes and reduce the risk of damage.

As I live in the tropics, i know from what i just saw with my mother's guitar that leaving something in its case for a long time can lead to mould. So now i'm inclined to put those little silican bags in any case where the instrument might get left for some time.

But on my travels where my uke is likely to take a beating in all forms as i'm on a bicycle and it will only be protected by my clothes inside my bag if it will fit, or strapped to the top wrapped in something and plastic. Its going to get a bit hot some days and it will probably get the odd splash of rain on others so I will just have to be on alert to protect it as much as possible from whatever onslaught nature sends out that day. hmm maybe i should look into getting a "dry bag" for it. We're on teh road for a year so it will be interesting to see how well it holds up.

And i haven't even said anything about getting banged about. This is bound to happen. I dropped my laptop once on a six month tour so I have to expect that similar is highly like with my uke.

teryg · Aug 22, 2016

I'm mostly concerned about it because sometime over the years one of my guitars developed some finish problems due to something with humidity (or temperature, I suppose). The instruments are always stored in my living space, where I'm comfortable though sometimes aware of dryness from heat or air conditioning. I suspect this happened years ago when I used wood or a kerosene heater to help heat a house. But since I'm not sure when or how it happened, I've gotten a little gunshy about my new ukes. Maybe that's not necessary as I no longer use wood or kerosene. It can get up to the 90s and sometimes 100s here in the summer, and down into the 20s, occasionally lower, in the winter. We do have air conditioning which has run a lot this summer, and hot water heat in the winter. And the ukes will sometimes travel in my car in all seasons. But perhaps none of that is enough to do damage to the finish.

stevejfc · Aug 22, 2016

AndieZ said:
I'm trying to understand this a little better becuase most of the above is a bit vague and or ambiguous to my mind. I live in a tropical climate where dryness isn't an issue, however i will be travelling over the next year and i will have other issues. Dryness will probably come up.

So this is my understanding so far. The big problem is rapid changes in humidity. If something dries out quickly, its likely to cause cracking. If the uke gets wet, and i mean wet, the wood will swell up and can warp. (i've seen that with my sister's wood floor before it got sealed.

So the aim is to minimise the extremes and also the speed of humidity change. When i bought mine the salesman just told me to keep it covered. This will help slow down any humidity changes and reduce the risk of damage.

As I live in the tropics, i know from what i just saw with my mother's guitar that leaving something in its case for a long time can lead to mould. So now i'm inclined to put those little silican bags in any case where the instrument might get left for some time.

But on my travels where my uke is likely to take a beating in all forms as i'm on a bicycle and it will only be protected by my clothes inside my bag if it will fit, or strapped to the top wrapped in something and plastic. Its going to get a bit hot some days and it will probably get the odd splash of rain on others so I will just have to be on alert to protect it as much as possible from whatever onslaught nature sends out that day. hmm maybe i should look into getting a "dry bag" for it. We're on teh road for a year so it will be interesting to see how well it holds up.

And i haven't even said anything about getting banged about. This is bound to happen. I dropped my laptop once on a six month tour so I have to expect that similar is highly like with my uke.

I live in the tropics too, or southwest Florida, where I'm told we are the 1st city in the tropics (not sub-tropics) in North America. We run air conditioning here nearly all year round. If not, mold develops quickly and everywhere. Of course the a/c kills the humidity, and left on it's own would lower it to around 20 -30%. Hence, I humidify all my solid wood. instruments.

AndieZ · Aug 22, 2016

Hi steve, Bad architecture makes airconditioning essential in the tropics. These days more and more people here are using aircon but i don't think anyone has it on in winter except maybe the hotels.

We live at 16.48 South latitude. My sister's house has good cross breezes but the time my dad shut the house up for a cyclone and forgot to open it up again, the ceiling went mouldy. I was away and when i got back OMG. I suspect that's when the guitar went mouldy too. This house has been standing for three years now and it hasn't shown any other mould. And I've still not cleaned the ceiling. Tropical houses should be light and breezy with lots of ceiling fans, otherwise you need airconditioning to keep them cool and mould free. Bessar block/concrete and small windows and big walls is bad for the tropics but of course that's the cheapest building material so its overused. Local council regulations don't help either.

Rllink · Aug 22, 2016

AndieZ said:
Hi steve, Bad architecture makes airconditioning essential in the tropics. These days more and more people here are using aircon but i don't think anyone has it on in winter except maybe the hotels.

We live at 16.48 South latitude. My sister's house has good cross breezes but the time my dad shut the house up for a cyclone and forgot to open it up again, the ceiling went mouldy. I was away and when i got back OMG. I suspect that's when the guitar went mouldy too. This house has been standing for three years now and it hasn't shown any other mould. And I've still not cleaned the ceiling. Tropical houses should be light and breezy with lots of ceiling fans, otherwise you need airconditioning to keep them cool and mould free. Bessar block/concrete and small windows and big walls is bad for the tropics but of course that's the cheapest building material so its overused. Local council regulations don't help either.

We have two homes. The first is in Iowa, and during most of the year the humidity is quite high. In the winter it can get a little dry, but we aren't there most of the winter. Our other place is in San Juan, Puerto Rico. We live in a two hundred year old building that it is on the national historical register. We have to maintain much of the original architecture, so we have windows that open out into the courtyards and ceiling fans. We do have air conditioning in the bedrooms, but we only run it at night. No problem with low humidity in San Juan.

Humidity and ukuleles?

Dan Gleibitz

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stevejfc

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Mivo

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Rllink

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Dan Gleibitz

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AndieZ

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teryg

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stevejfc

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AndieZ

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Rllink

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