I found this updated article on guitar humidification. For those who hate clicking links, search on "Clouds or No Clouds: All You've Ever Wanted to Know about Humidity and Guitars".
Maybe I'm all wet, but it never hurts to keep up on this topic...
My rule of thumb is if I am comfortable, so are my instruments. Lately we've been enjoying dew points in the mid 70's and LOTS or rain. My instruments have never sounded better. Six months from now this is really something to keep our minds on, Thanks for sharing.
I got a 1984 Stiver F in 1989 from Elderly Instruments in Lansing Michigan. At the time, I lived in a drafty, and hence very dry, old farm house in South Dakota. Three days after it arrived, the top cracked from the treble f-hole up along side the neck extension. BUMMER! My point being, it doesn't take long for damage to occur when the wood shrinks due to drying.
It doesn't seem that excess humidity does damage, unless you consider when the Gibson factory in Nashville flooded. Any experience or knowledge with over-humidifying?
No experience with overhumidification here, just the opposite. I used to be a lot lazier until I had a bridge lift on a new guitar. It was winter, and my house was bone dry. After that, I got a lot more religious about humidifying my instruments.
Kind of sad for a meteorologist to overlook something like that.
'Like a Chid' 2 days
'Like a Child' 2 days
'4/4 German Violin' 8 days