In MMD 060521, Dave Jones asks, "Where can I get replacement pouches
for a Universal player piano?"  If you do find someone that makes these
pouches, make sure that they use leather, and not the original synthetic
Perflex material.  It seems that 20 years is all you get out of the
original pouches, after which they start opening up and notes start
dropping.

To fix them, I disassemble the stack and remove the white plastic rings
that hold the old pouches.  Remove as much of the old material from the
rings then take #80 grit sand paper and hand sand the rest off.  It might
take three sheets of sandpaper since the rubber and old glue loads up
and makes the sandpaper worthless.  Now take an Exacto knife and use it
to remove any signs of old glue found on the inside of each ring.

The next important step is to get the right dish in the leather.  This
is how loose the leather is, so when it expands when air enters the
pouch well, it operates the valve.  Too little dishing will give you
problems when the leather shrinks due to moisture.  Too much will also
give you problems with the leather binding the valve stems at the side
as it stretches and surrounds the valve stem.

I have a small jig that consists of about six felt punchings glued to
a thin piece of wood, 1.25 inch apart.  The felt punchings are from
PPCo, #1685, and are .25 by 1/8th inch thick.  I also have a small ring
cut from a 1/2-inch copper pipe that is cut 3/8 inch short with all
edges rounded smooth.  For glue I use a product used in acrylic painting
called "Golden Medium #GAC-100".  This glue seems to have a higher
gluing strength than the PVC-E glue but is much thinner.  You should
also have a large sheet of waxed paper available, which will be
explained later.

The procedure is

1) Take the thin pouch leather and place it over the felt buttons on
the wood jig, smooth side up.

2) Put the 1/2 inch copper ring over one of the felt buttons.  This
gives a small dish to the leather, and helps from pulling glue onto the
leather when lowering the white ring into place.

3) Apply glue around the edge of one of the white rings being careful
not to get any on the sides.  I use the nozzle on the bottle to apply
the glue.  This puts a thin bead of glue on the edge of the ring which
is too much glue.

4) Take the glue side of the ring and drop it onto the waxed paper.
This removes any excess glue.  If this is not done, then the glue will
run to the inside area of the pouch and make it stiff and reduce the
lifting power of the pouch.

5) While holding the white ring in one hand, put your index finger from
the other hand through the white ring and lower your finger onto the
copper ring.  Put pressure on the copper ring so the leather on the
outside is somewhat smooth and contacting the wood of the jig.  Now
lower the white ring and press it to the leather.  Your pouch should
now have the right dish to it and you didn't drag any excess glue into
the working part of the pouch.  Hold it for about 5 seconds to let the
glue soak into the leather.

6) Now repeat the process using another one of the punchings on the
jig, being careful to not disturb the others that were just glued.

After 10-15 of the white rings are glued, I rough-cut them from the
leather and do the final trimming with scissors.  You must remove all
leather and glue that remain on the outside edge of the ring.

It would be best to seal the leather but I have had good results with
just testing each pouch and re-leathering any pouches that leak more
than the others.  I try to use the best leather that I have.  With the
pouches so small, any extra stiffness that is added due to the sealing
seems to outweigh the benefit of being perfectly airtight.  I know this
might rub some people the wrong way since the original pouches were
100% airtight and the bleeds were selected due to this.  I am finding
out that leaving the pouches unsealed is okay.  If you do try to seal
the pouches, make sure that the valve stem doesn't stick to the leather
pouch.  It must be completely free and slide back and forth so the
rubber seal valve will seal tight against its seat.

This stack is one of the best airtight stacks built.  _Do not,_
I repeat, do not over-tighten the 40 or so screws that hold the valves
down to the main aluminum block.  Doing so will bend and warp the two
aluminum plates and they will never seal properly again.

You should be able to use your lungs to check for any sticking
inoperable valves.  This should be done before putting the 2-tier stack
together.  You will have to place the stack in its normal operating
position for this test to be done.  To close off the sides of the
tiers, I use masking tape or you can use the mounting plates that hold
the whole thing together.  With scrap pieces of tracker bar tubing,
use one piece of hose to close off two of the nipples.  It will take 40
pieces of tubing to close all 80+ nipples on the stack.  Use a hose where
the vacuum pump goes and inhale with your lungs to check if everything
is okay.  Seal any big holes that you may have missed.

If the valves are not seating properly, the pneumatics will rise up
a little and then drop as more vacuum is applied.  If you have done
everything properly, you can fix this problem by just putting vacuum on
the nipple of the offending valve and try the test again.  What this
does is lower the pouch just enough so that the valve stem will slide
to one side and the rubber seal will then rest flat against the seat.
When all of the valves are seated properly, you should have very little
air entering your mouth from the stack.

To check if the valves will pull up the key pneumatics, remove 10 of
the tracker bar tubes (20 nipples open) and then use your mouth and see
that they all close.  Do the same thing to the remaining 20 valves on
the tier.  Do the same tests on the second tier and when everything is
working properly, you can permanently seal the stack the way you found
it by using 100% Silicone Sealant bathroom caulk.

Pete Knobloch