Low Humidity Best?

[Lance Lafargue]

I thought that since the piano was built at around 40%, drying it too far
beyond that would shrink the wood and risk glue joint failure.  I never dry
the older pianos in Louisiana past 48%.

Question:  At what humidity level does metal rust significantly?  

Lance Lafargue, RPT
New Orleans Chapter
Covington, LA.
lafargue@iamerica.net

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> From: Michael Jorgensen <Michael.Jorgensen@cmich.edu>
> To: pianotech@ptg.org
> Subject: Low Humidity Best? 
> Date: Thursday, January 08, 1998 3:23 AM
> 
> Hello List,
>      I am interested in your opinions concerning humidity.  In Michigan,
> most homes simply can't handle 40 percent as windows drip and rot in
> winter.  My father, Owen Jorgensen, keeps his Steinways at a constant 25
> percent, using only a dehumidifier in the summer.  Every few weeks he
> "fine tunes" his dehumidifier by listening to whether the lowest tenor
> strings are going flat or sharp with respect to the rest of the piano.
> (sharp notes mean dehumidifier must run more).  His 21 year old B has no
> cracks or compression ridges, is all teflon which never makes noise and
> never needs work, and he hasn't tuned the pianos in years, only touching
> up once in a while, yet they're in perfect tune all the time.  Both are
> played alot, the pitch stays right up, the strings are not rusty, and
> action parts work beautifully.  The A is all original except
> hammers/shanks and has many cracks but is 94 years old and likely had
> them before any of us were born. I see an awfully lot of "humidity
> controlled" pianos kept around 40-50 percent that seem to be falling
> apart and rusting away.  Comments?
> Mike Jorgensen RPT