Silicone sealant should not be used for gluing the pouches to the pouch
board.  In fact, silicone should not be used anywhere in the player
piano except for sealing pouch leather.  Here are two good reasons:

1) The next rebuilder will not be able to remove the silicone from the
lip of the pouch board.  This silicone will enter into the pours of the
wood and can be difficult to remove.  The only way is to scrape the
wood down with a razor blade.  This does not always clean the wood up
enough to get the hide glue to stick properly.  Using water soluble
hide glue doesn't have this problem.

2) There can be significant forces on the pouch leather when the piano
is pumped hard.  Also think of someone using a tracker bar pump to
remove dirt from the hoses.  Every time these forces are placed on the
pouch, it can peal the inside edge of the pouch away from the wood and
will eventually fail.  This has been proven to not be a problem with
hide glue.

I would not even use it to glue the pouch lifter disks to the pouch.
You only want 1/8 inch diameter of the glue holding the disk to the
leather.  You can do this with hide glue and you know that it will
hold.  With silicon, it will be very hard to get such a small glue area
to hold as efficiently as the hide glue.

As far as using Silicone Sealant as a pouch sealer, go ahead and use it
as long as it is thinned to a consistency of water before applying it
to the leather pouch.  Never apply it directly to the pouch since it
will stiffen the leather.  Just remember that the thicker the sealer is
before you apply it to the leather, the more difficult it will be for
the pouch to move freely.  This will affect the maximum rate that the
valve can operate at.  Remember that a little goes a long way.

Another 'no no' is using silicone seal to replace a leather gasket.
Never use silicone to hold leather to wood or wood to wood.  Always
use hide glue.

Pete Knobloch (Tempe Arizona, USA)