I am grateful to all the people who replied to my question about
using old pneumatic cloth for recovering the finger pneumatics on the
Seabreeze Verbeeck organ.  The consensus was not to, that the age of
the cloth would outweigh any chance that it was originally better than
cloth being sold today.

Based on the replies I received, if I were going to use rubberized
cloth, I'd use Rick Alabaster's Australian cloth, available from the
Leather Supply House and from Schaff (if they haven't mixed the good
stuff with cloth acquired in the takeover of APSCO).  The advantages
of it are price and ease of gluing, offset by the disadvantage that
it wears faster than other material, particularly if you let it take
a hard crease.

Polylon seems to have a varied track record.  Some users have reported
delamination problems, others found it impossible to glue.  But Polylon
problems appear to be related to how it was made.  The Polylon being
sold today by Schaff is reported to have no structural problems and it
lasts much longer than rubber-coated cloth.

The mold release agents used in Polylon manufacture seem to be the main
cause of gluing problems, and I received several suggestions for coping
with that: (1) treating the side to be glued with a cleaner-solvent
such as lacquer thinner, (2) scrubbing it with ammonia, (3) running the
cloth through the washing machine with strong detergent.

PVC-E glue (which PPCo sells as "plastic glue; catalog #320) was the
recommended glue for Polylon, although after the washing machine
treatment it was successfully glued with ordinary hot hide glue.

So Polylon's advantage is longevity, offset by the care needed to buy
from a reliable source and the preparation needed to insure a good glue
bond.

A couple of respondents to my question suggested using leather,
specifically the thin kangaroo which Columbia Organ Leathers has
recently begun to stock.  I happened to have a couple of square feet
of thin kangaroo left from organ work I did last fall.  So I decided
to experiment and cover one pneumatic with the kangaroo, using a strip
about 1" x 9", which is about what each finger pneumatic takes.  First
I sealed the strip with silicone (Dow Corning 3140 Flowable Silicone
was recommended, but I used some regular silicone, thinned with naphtha).
That made the kangaroo every bit as airtight as rubber cloth.

I glued the kangaroo to the cleaned-up wood of the pneumatic boards
with Columbia's High Tack Fish Glue.  The bond was nearly instant and
required no clamping.  Thin kangaroo is a dream to work with, presenting
no problems in conforming to corners, as rubber cloth sometimes does.
One pneumatic wasn't enough; I went off the deep end and covered all
the pneumatics I could until I ran out of kangaroo -- about one-third
of the total number of 55 pneumatics.  Today I ordered another kangaroo
skin to finish the job.

Kangaroo is tougher than tan pouch leather of comparable thickness,
impossible to tear with your hands.  I was told that it has not been
one of Columbia's big sellers, either because of its cost or people's
unfamiliarity with its superior qualities and its ease of use --
bordering, as I said, on delight.  But if the kangaroo lasts as long
as I think it will, it will pay for itself easily.  The snare drum
pneumatics on our organ wear out very quickly and require re-covering
with rubber cloth almost every year.  Next time it is time to re-cover
them, it will be with kangaroo, and then we will see whether it fills
its promise.

If anyone reading this would like small samples of Columbia's thin
kangaroo, both unsealed and silicone sealed, I will send them.  (I am
not an agent for Columbia Organ Leathers, just a satisfied customer
who wants to see them continue to stock it.)

Matthew Caulfield (Irondequoit, N.Y.)