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PostPosted: Tue Nov 05, 2019 2:31 pm 
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paddler wrote:
I am under the impression that warmer air holds more moisture, so absolute humidity should increase with global warming.
While the air can hold more moisture, there are some places in the world where no more moisture is available. It may get wetter where you are and where I am, but much of the territory between will get drier, because what moisture is available will evaporate in the warmer air and be carried away.


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PostPosted: Tue Nov 05, 2019 2:57 pm 
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While I'm a complete believer in human caused climate change, I'm not sure it will make things worse for flute cracking. I look at those pictures of The Chicago Irish Music club in say, 1903 and think weather in Chicago was really extreme--hot humid summers, extremely cold winters, and all their heat would have been from furnaces and radiators, so dry dry dry. Is flute cracking worse now than it was in, say, 1900? It might be better because more places have better insulated, better controlled temperature.

It's also not exactly clear how climate change will manifest in individual countries. Ireland is much warmer than Virginia in the winter, despite it being as far north as Labrador, which is extremely cold. It's not like "everything will stay the same, except four degrees warmer." I actually think the maritime climates of England and Ireland are going to be the most altered, maybe to wind up with the more extreme seasonal weather variations typical of other countries in the same latitude.

Of course if the real problem with flute isn't temperature changes, it's the moisture/drying cycle, then it's probably worse that we have more air conditioning and more, better heating.


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PostPosted: Tue Nov 05, 2019 6:41 pm 
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PB+J wrote:
I look at those pictures of The Chicago Irish Music club in say, 1903 and think weather in Chicago was really extreme--hot humid summers, extremely cold winters, and all their heat would have been from furnaces and radiators, so dry dry dry.

That's an interesting comparison, although I wouldn't assume the indoor humidity was as dry for those fluters and pipers at the turn of the 20th Century as it is in modern/recently built Chicago homes.

They didn't have forced air HVAC heating systems back then, which as I understand it, is more prone to dry out the air than radiant heat from a fireplace or wood stove. Installed heating systems in the better homes would have been hot water or steam radiators driven by a boiler. An old steam radiator can even act as a humidifier through leakage from the pressure relief valves.

Many homes in the early 20th Century were also probably draftier, not as tightly sealed and insulated as a modern home where forced air heating can dry out the indoor air. I can attest to that, living in a Victorian wood home built in 1888. It had insulation blown into the exterior walls and attic by a previous owner, but this place leaks like a sieve when the wind is blowing, due to ill-fitting windows and a thousand small gaps in the woodwork.

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Is flute cracking worse now than it was in, say, 1900? It might be better because more places have better insulated, better controlled temperature.

That's true for those of us who carefully maintain safe humidity. For those who aren't aware of the danger though, it could be worse now. because we use heating systems that are more prone to drying the air and our houses are sealed tighter.


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PostPosted: Tue Nov 05, 2019 7:31 pm 
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Tunborough wrote:
paddler wrote:
I am under the impression that warmer air holds more moisture, so absolute humidity should increase with global warming.
While the air can hold more moisture, there are some places in the world where no more moisture is available. It may get wetter where you are and where I am, but much of the territory between will get drier, because what moisture is available will evaporate in the warmer air and be carried away.


When moisture evaporates it doesn't go away, it is still contained in the air that absorbed it.
If that air is cooled down again, say by air conditioning, then the moisture comes back out,
or at least the relative humidity increases. And as far as I know, relative humidity is what
determines how fast we lose moisture from our flutes.

If the air carrying the moisture blows away then it is replaced by air from elsewhere,
which by definition should have more moisture than the air that blew away, given that we
are talking about a location that has no more moisture left locally. For an example,
consider the case of inland air heating under a desert sun and rising, inducing a sea
breeze that brings cooler, moister, air in from the sea to the land.


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PostPosted: Wed Nov 06, 2019 2:47 am 
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paddler wrote:
When moisture evaporates it doesn't go away, it is still contained in the air that absorbed it.
If that air is cooled down again, say by air conditioning, then the moisture comes back out,
or at least the relative humidity increases. And as far as I know, relative humidity is what
determines how fast we lose moisture from our flutes.


Problem with cooling by air conditioners is that the cooling takes place in a heat exchanger inside the machine, where the moisture in the air condenses out onto the cold fins, and is transported away in the drain pipes leading from the machine. So an air conditioner reduces the relative humidity in the room in both summer and winter.

[quote]If the air carrying the moisture blows away then it is replaced by air from elsewhere,
which by definition should have more moisture than the air that blew away, given that we
are talking about a location that has no more moisture left locally. For an example,
consider the case of inland air heating under a desert sun and rising, inducing a sea
breeze that brings cooler, moister, air in from the sea to the land.

That works for regions that are close to the sea but not for the inland. That's why we in coastal NSW can reasonably expect a wetter future but our inland cities can't. I'd expect the same in the US. Small islands like Ireland I imagine don't really have an "inland" - you're never far enough from the sea - but I'm open to being corrected!

According to the Climate Change Australia website on humidity:
• There is high confidence that inland humidity will decrease in winter and spring as well as annually, and there is medium confidence in declining relative humidity in summer and autumn.

We're clearly going to need to spend more of our time in the pub!


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PostPosted: Wed Nov 06, 2019 8:06 am 
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Living here in Somerset where the sea air slides up over the Mendip Hills the only bit I understood was: '...then the moisture comes back out'.

And obviously the part about spending more time down the pub. :wink:


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PostPosted: Wed Nov 06, 2019 8:21 am 
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Not to pour cold water on all the focusing on detail but don't you think that if the effects of climate change fully kick in, cracking flutes are not even going to be in the top twenty of your worries?

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PostPosted: Wed Nov 06, 2019 11:14 am 
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So flute players living in inland Australia may experience decreased humidity with climate change,
whereas those living nearer the coasts will experience increased humidity? OK.

I think Mr Grumpy is on the right track here. Perhaps what the majority of flute players, who live
nearer the coast, will need is a flute that floats!


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PostPosted: Wed Nov 06, 2019 12:36 pm 
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paddler wrote:
If the air carrying the moisture blows away then it is replaced by air from elsewhere,
which by definition should have more moisture than the air that blew away, given that we
are talking about a location that has no more moisture left locally. For an example,
consider the case of inland air heating under a desert sun and rising, inducing a sea
breeze that brings cooler, moister, air in from the sea to the land.

https://www.ctvnews.ca/mobile/sci-tech/zimbabwe-s-severe-drought-killing-elephants-other-wildlife-1.4672173
Quote:
"Climate change is real for sure, we are witnessing it."
- Munyaradzi Dzoro, Zimbabwe parks agency wildlife officer


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PostPosted: Wed Nov 06, 2019 3:40 pm 
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I'm not saying that climate change is not real. I just think we need to
be careful not to confuse a bunch of different issues.

First, absolute humidity and relative humidity are not the same thing. What
we care about regarding flute cracking is relative humidity. To understand
the difference, consider what happens when dew forms. We have warmer air
that is holding a certain amount of moisture. As it cools it is unable to hold
as much moisture, so some moisture condenses out in the form of due. This
happens because the relative humidity has increased to 100% as the air cooled,
even though its absolute humidity is decreasing.

Indoor relative humidity does not directly track outdoor relative humidity.
Indoor relative humidity depends a lot on the temperature difference between
the indoor and outdoor air. Indoor relative humidity drops if we heat the
air and increases if we cool it.

AC units cause water to condense out of the air because they cool the air and
cooler air can not hold as much moisture. So the absolute humidity of the air
drops, but the relative humidity of the air can still increase.

Our problems with cracking occur more in winter than summer, in most places,
because that is when our indoor relative humidity is lowest. Warmer winters will
help that.

Lack of rainfall or standing water do not necessarily indicate dangerously low
relative humidity for flutes. For example, in the drought conditions referenced
in the article about Zimbabwe summers, relative humidity outdoors is still 37%
or so, which is far higher than it is inside many US households in winter, and not
terribly dangerous to our flutes.

The majority of people who play our flutes don't live in these inland, desert areas
that are far from the coast. A few do, sure, but not many.


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PostPosted: Wed Nov 06, 2019 6:08 pm 
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Mr.Gumby wrote:
Not to pour cold water on all the focusing on detail but don't you think that if the effects of climate change fully kick in, cracking flutes are not even going to be in the top twenty of your worries?

Indeed, Mr.Gumby. I'm naturally optimistic (although the dismal lack of response of our Government to the issue is sorely testing that!) So I'm banking on the world coming to its senses in time to avert total disaster. (Note to World: c'mon you lot, you've got till the end of the week...)
So, trusting I'm right to be optimistic and we can avoid reliving Mad Max, we will still have to adapt to a lot of change that is already locked in. And I'm thinking that plunging humidity in the inlands and rising humidity in the coastal regions is going to be the one that effects flutes most. And possibly dramatically, depending on the numbers.

Paddler's "flute that floats" for coastal fluters poses a bit of an issue, doesn't it. Boxwood's density is around 1.0, but tuning slides, rings and keys are going to be a liability. All our other flute timbers sink very determinedly. Especially Delrin (1.4)! Flotation chambers?


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PostPosted: Wed Nov 06, 2019 6:24 pm 
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Terry McGee wrote:
... I'm still happy with my New Improved Tuning Slide design, http://www.mcgee-flutes.com/fluteslide.html, which seems to be enough to get around these issues...


A very elegant solution to a problem that is happening now. Well done!


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PostPosted: Wed Nov 06, 2019 6:26 pm 
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Now, I've glued up the crack in the wooden barrel I mentioned earlier up, and was about to ream out the inside to allow the metal slide back in, when I realised the absurdity of doing that. This barrel has sat around down here at the coast for about two weeks, so will have become at least part equilibrated to our higher humidity. So, before I ream it I'm going to bring it back down to around the bottom of inland-like humidities. I popped it into the environment chamber this morning, aiming at 30%. It was about 60% here at that time.

To determine when we've got there, I've measured its weight (a massive 22.54gms!), and will monitor that until it stops dropping. Interestingly, the ID of the wood is 20.81mm, while the OD of the metal is 20.85, so even at 60% humidity, the metal won't go in.

The risk of course of overdoing this is that the metal slide might come loose again after some a good spell of really damp weather (if we ever see such a thing!), but I see that as less of a problem than more cracking. Pretty easy to reglue the slide.


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PostPosted: Wed Nov 06, 2019 6:28 pm 
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D Mc wrote:
Terry McGee wrote:
... I'm still happy with my New Improved Tuning Slide design, http://www.mcgee-flutes.com/fluteslide.html, which seems to be enough to get around these issues...


A very elegant solution to a problem that is happening now. Well done!


Thank you! The question becomes "are there better approaches?" we could adopt?


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