I read with interest D. L. Bullock's account of restoring a late
version Aeolian player with lots of plastic parts.  If ever there was
an example of "GIGO" ("garbage in, garbage out"), this Aeolian product
of the 1970's certainly is the epitome.

As Bullock described the valves in detail, it brought back vivid
memories of my own experiences with that product.  When I first worked
on one of these pianos, I couldn't believe the valve blocks were
actually glued on.  Next, I discovered that indeed these valves are
gapped at around .080 inches!  But the most curious thing that he
mentioned, and again I concur, is that the sponge valve material was
hard and not a suitable medium for the job.

It was after my experience with this Aeolian product that I began re-
searching the concept of sponge neoprene as a suitable valve material.
It seemed that the Aeolian design concept was good, but it was just
poorly executed .

I was living in the Chicago area at the time, and access to manufactur-
ing material in that area was virtually unlimited.  Also, there were
many experts in material selection.  What I found, was that sponge
neoprene could be had in many different grades.  More importantly, the 
higher grades have an extremely long life expectancy if not exposed
to ultraviolet light.

So the huge array of choices of sponge neoprene encompasses closed
cell, open cell, skinless, skin on one side, skin on two sides,
varying degrees of firmness, and so on.

I started making valves using high grade sponge neoprene.  When I was
rebuilding for a customer, I offered a choice of sponge or leather.
The sponge that was manufactured in 1976 and punched to my specifica-
tions is still supple, today.

There are two pianos in my collection that have neoprene sponge valves.
One is a 7-foot Mason and Hamlin Ampico A, the other is the small baby
Ampico spinet.  These pianos have aged 15 years since the sponge
installation, and no loss of valve function has occurred.  The stacks
remain almost 100% airtight and the valves have required no servicing
since installed.  While the big Mason piano plays impressively, the
most incredible performance (relatively) comes from the little spinet
which plays within a huge dynamic range!

The purpose of this post is to alert readers that not all Neoprene is
bad.  True, the plastic valves made by Aeolian were horrible, but it
was a poor grade of rubber that they used.  As an optional alternative
to leather, sponge neoprene can outperform any leather valve and even
match longevity.  It's not all bad!

Bob Taylor

 [ Like Craig says, "Test, test, test", and be sure to specify the
 [ important qualities when you buy material.  If you want gaskets
 [ which won't crumble in the ozone atmosphere of the big city,
 [ you must chose a particular type, and probably pay more.  I have
 [ no respect for a company, like Aeolian, which produces a product
 [ without any control over the quality of materials.
 [ -- Robbie