Hans van Oost describes the use of zephyr for small primary cushion
pouches.  I have used this material for small pneumatic devices in
organettes and player pianos, particularly for the primary action of
German pianos which often used cushion pouches glued to a flat pouch
board rather than the more usual circular leather pouches glued over
a machined recess in the pouch board.

Good quality zephyr is around 1.5 to 2 thousandths of an inch thick
and is readily available in the UK, although it is getting rather
expensive.  Last time I paid GBP 18 for a single piece, about 18 x 9
inches.  I have always been curious to know exactly how it is made,
and from what.  Can someone please enlighten me and the MMD at large?

Unlike leather, which comes in animal shaped pieces and therefore
giving a clue to its origin, zephyr comes in rectangular pieces as if
being cut from a larger piece, or even being manufactured as a sheet.

Hans also mentions his Mignon organette.  The Mignon is an unusual
organette on a number of counts.  Firstly, it is one of the few, or
maybe the only, German organette that works on suction.  Secondly,
it has a unique primary action.  The more usual primary action in a
'two stage' organette is found in the Celestina or Seraphone which
employ a primary pneumatic with a long and narrow moveable top board
with the sides covered in very thin leather.

Zephyr is an ideal replacement for this leather, if damaged, as it is
almost impossible to obtain leather thin enough these days.  The Mignon
primary action, however, comprises two rows of rectangular cavities
fabricated from thin wood with a pivoted arm moving in and out of each
cavity.  The arm operates the reed pallet and is moved by a very thin
membrane glued over the top of the cavity but with sufficient slack to
be pushed into the cavity by the arm.  The membrane must be very thin
and supple.

I was advised by a Dutch restorer to use something called "Gold Fleece".
Luckily he supplied me with enough for restoring my Mignon.  Gold
Fleece has to be prepared by the user, being supplied as a wet bundle
soaked in brine.  After careful washing and rinsing in disinfectant it
is pinned out to dry on a flat board.  The resulting membrane is only
half a thousandths of an inch thick.  In spite of this it has adequate
strength to operate the Mignon pallets and my Mignon has been working
faultlessly for the last ten years.

When I asked about the origin of Gold Fleece I was referred to the back
end of a horse!  Maybe Hans or one of his friends could enlighten us as
to the exact origins of this interesting material?

Best regards from Great Britain,
Nicholas Simons