I now use natural gum rubber for these Ampico applications.  I have
dies to make the Ampico expression gaskets for the no. 2, 4, 6, and
7 outside valve boxes.  I also use this material for the three
pneumatics but I cut them out myself without a gasket.

If you will send me $20.00 via PayPal I will send you enough gaskets
(8) for two expression boxes and some material for you to cut your own
gaskets for other things you might need.

I use natural gum rubber because the thinnest Coroprene (cork with
neoprene) product I have gotten in past was way too porous, with it
leaking between the cork pieces.  The gum rubber I have is the same
thickness as the original gasket for the pneumatics, and it works
without putting a shim on the inside button of the valve or having to
deepen the countersinks for the pneumatics.  I think it is 3/64" thick,
if memory serves.  I just know it is perfect and totally airtight if
both surfaces are sanded on glass smooth.

When working with natural gum rubber, be sure to use sharp cutting
tools and don't pull a section that did not cut: cut it again.

D.L. Bullock    St. Louis
www.pianoworld.us