Barry Dennis asked about mold in a piano he rebuilt in 1978.  About the
same time period I rebuilt an Ampico that also was in a house located
by a river.  The customer called me about a year after it was rebuilt
and said it wouldn't play right.

When I took off the belly cloth there was mold everywhere: on the
hoses, wood, tubing, V-belt, cast iron pulley, top of the belly cloth,
etc.  I looked at the underside of his furniture and there was mold
there also.  I concluded that the mold was actually growing wherever
any dust settled.

With the right conditions you would get mold regardless of what
materials you use.  It takes more than just humidity.  I service a
couple of PianoDisc pianos that are in very high humidity conditions.
One sets on the deck next to an indoor swimming pool.  They have lots
of rust on the metal parts and other high humidity problems, but so far
no mold.

John Dewey
East Central Illinois