I bought a big rectangular container for my flutes
and wooden whistles, put in a sponge–the humidity
is around 70.
Well, tuning slides seem to be affected. So
the Copley slide is now very loose–a consequence
I think.
Meanwhile the Abell whistles are so tight it’s
hard to fit the tubes to the heads.
Weird, I say. What’s going on.
Oh yes, an awful mold started growing over
things.
Jim, that’s mildew, and it needs to be cleaned off. Your container will have even more spores than normal throughout, now, and should be cleaned as well. I suspect that the only preventative measure for this is to remove the instruments from their cases at least once daily to allow for airing. Mildew will ruin leather and fabrics, and I expect will compromise some woods, as well, so you need to address this. The thing about mildew is its ability to spread rapidly especially in still, humid, undisturbed environments. Plus it doesn’t smell so good.
As for the tuning slides, I’ve had people swear that humidity affects metals too, but I’m no metallurgist. The opposite effects you mention make me wonder if that’s a mistaken assumption. I’m pretty sure that there are at least one or two Chiffsters who have some expertise in this, as I recall from past posts, but I can’t recall who, sorry.
In any event, get rid of the mildew pronto, and be sure to give your instruments regular airing.
Best,
N
I have kept my Copley flute in a larger plastic container the entire nine months I have had the flute. Both the hygrometer inside the pistol case
which Dave provides and the one inside the larger plastic container usually
average 70-75 % The tuning slide moves with the same ease it has
since the flute arrived. I have never noticed the first hint of mold or
other wildlife. I might add that the lid to the outside plastice container
has a loose fit. The flute gets played almost every day.
Yeah, Stan, the near-daily playing may be the trick; airing it out, again, is what I presume to be key. Once I left my pipes in their case for abt. 4 days and you wouldn’t believe the mildew…on the other hand, all that leather had to offer something tasty for sure, and the wood got a dusting, too. I did not find it a good thing. The wooden parts came out OK after a cleanup, but some of the leather was definitely affected. Fortunately I caught it in time.
N
The sponge in a closed box reminds of a cigar “humidor”. However, these are opened, and thusly ventilated, pretty often. In any case, cigars need some free air once a week, or will mildew, and then you have to save them before late, and disinfect the box.
For instruments, I would drill vents in such a box. There are well ventilated cabinets sold for bread. Interestingly baguettes and flutes*, or low whistles, fit the same format… 
)Right. Well, maybe I’m jumping to conclusions about
the tuning slides. Still the Abells were OK before
I humidified them. But the point is well taken.
The mildew was mostly on, and in, the cases
for the abells, which I had left in the cases
with the cases open. Catch me doing that again!
Thanks to all
If I put my flute in my humidor will the cigars affect the flavour of my flute? 
or will I only be able to make Cuban music? (Sorry to make all you embargo-bound American cigar smokers jelous)
If you are keeping your flute in a humidified envronment (I do, it’s called Scotland) then you should allow air to circulate regularly to prevent mould.
I’m off for a Cohiba Robusto 
Cheers
Graham
The embargo has done very little to keep Havanas out of the hands of the determined smoker. Lots of shops have them under the counter. All you need to do is to establish a relationship until they stop thinking you might be an ATF agent.
I prefer Hondurans (la Finca) anyway.
How old are these flutes? I had a problem with my Thin Weasel flute (a tenon so tight I couldn’t even put it together). I had chalked this up to humidifying it, but it was brand new, so it may have been part of the ageing process. Glenn said he’d never seen that happen before.
My Abell whistle almost freezes every so often – it’s the silver tuning slide (it doesn’t happen to any of my other whistles). I take a Scotchbrite to the slide to take the tarnish off. It’s still be tight but not impossible.
PS – I’ve never had a mold problem, but I try to keep it below 65%. You might want to shell out 10 bucks for a humidifier rather than a sponge – sponges are notorious for harboring little nasties.
The Abells are about three years old.
Maybe I can humidify with wet cigars.