I have been lucky enough to have been taught many of my restoration
skills by some of the best men in this field, people with decades of
experience in restoring pneumatic mechanical musical instruments, as
well as possessing a high degree of personal integrity and character.
One of the greatest things I learned from my father was how to work
hard, how to be humble, how to listen, how to become a good man, and
most importantly which character traits create integrity. That advice
has never failed me and I will never forget it.

The MMD thread regarding pouch sealing has been educational and quite
interesting to follow.  I have been restoring pneumatic mechanisms for
about thirty years, and unless you're a complete idiot, you do tend to
learn a few things.  As with any good technician, I'm always open to
learning new things to improve my work.  As has been said here many
times, the effort is to have the end result meet or exceed factory
performance, while using traditional materials wherever practical.

Original information regarding methods of pouch sealing shouldn't be
shunned simply because of its age.  The factories always knew their
product best.  The American Piano Company wasn't in the business of
repairing problems in the field due to their use of bad materials.
Their job was to get it right the first time, to eliminate service
calls and to maintain a healthy profit margin.  I doubt that they would
have recommended a practice without testing it extensively in the
factory beforehand.

It is my opinion that all pouch leather should be sealed in a player
mechanism or a pipe organ action.  Sealed pouches give you a strict
point of reference, to which the bleeds or any other venting can then
and only then be accurately sized.  How can you possibly know what size
bleed to use if you don't start with well-sealed leather pouches?  No
two unsealed pouches are going to have the same amount of leakage, and
it would be difficult to accurately compensate for this when restoring
a player having a non-adjustable bleed system.

I have used thinned rubber cement to seal pouches since 1980.  It is an
item that should be in all professional rebuilding shops, because it is
100% appropriate and proven to be effective.  Art Reblitz advised in
the 09.06.14 MMD to let the machines speak for themselves.  I couldn't
agree more with that.  He and other professional restorers have
restored enough machines with rubber-cement sealed pouches to fill a
small airplane hangar.  Many of these machines were restored twenty
years ago or more and still play as well today as they did when the
restoration was done.  That's the best testimonial you can get, as far
as I'm concerned.

I tried egg white to seal pouches for a very short time in the past,
but my fear was that the egg white might attract insects who will feed
on the leather, just as they find zephir skin tasty to munch on.  Every
player action I have ever disassembled which used zephyr skin for
pouches has been found to be eaten full of holes, and in many instances
pouches were eaten until they were completely gone!  On top of this
problem, zephyr skin is prone to shrinkage.  For these two reasons, I
never use zephyr skin for pouches.

A pipe organ windchest action (which operates on pressure, not suction)
is identical in theory of operation to the pneumatic player piano
mechanism.  Tony Marsico's excellent submission to the 09.06.14 MMD
about his experience with the Austin pipe organ chest proves that pouch
sealing is a mandatory practice.  Tony isn't exclusively a pipe organ
enthusiast either.  His experience and knowledge in mechanical music
instruments is extensive.

The Ampico reproducing mechanism originally had its valve pouches
sealed with rubber cement.  The fact that an Ampico system must be able
to operate on low suction at times isn't what made rubber cement the
choice of sealer.  It was used because it worked, and it works well.
So, if American Piano Company felt that pouches needed sealing to
operate effectively on low suction, then any player piano action -
electric or otherwise -- that is even remotely expressive would need
sealed pouches, as they too must be able to operate on low suction
levels.  All of the player pianos I have restored using rubber cement
as pouch sealant work effortlessly on very low suction.

I'd like to comment on another factor that indirectly affects the
tightness of a pouch, one that is often overlooked: the wood
surrounding the pouch.  Pouch cavities should be drilled into tight
grained lumber, and the wood needs to be correctly sealed as well.
Channeling leading to the pouches likewise must be well sealed. But I
won't go into the specifics of sealing player action components here,
as it is not within the topic.

Excellent examples of restored Ampico pianos exist in many collections
open to MBSI and AMICA members today, and they have been playing just
fine on their newly rubber-cement-sealed pouches.  The Mason and Hamlin
model RAA Ampico model "B" grand restored by Larry Mangus resides in
the Sanfilippo American Room.  Also in the Sanfilippo collection is the
mammoth 1928 9-foot Knabe Ampico model "A" concert grand, which
received the touches of Chicago restorer Jerry Biasella.  There are
also equally magnificent Ampico pianos in the Krughoff collection.
Both of these collections are open for tours on a regular basis.

It has been erroneously stated here many times, especially recently,
that rubber cement can be likened to rubber bands in chemical makeup.
But assuming that all rubber cements are the same is ridiculous.
Just as there are fine, mid-grade, and economical brands of all
products, the same holds true for rubber cement.  I use "Best-Test"
rubber cement, made by the Union Rubber Company, Inc., of Trenton, N.J.
I also use their brand of thinner, called "Bestine."  "Best-Test" is
available through any better art supply store in quart or gallon cans.
It has been tested and  manufactured since 1923.  I am assured by Rich
Keller of Union Rubber Company that it is indeed not the same material
that rubber bands are made of, a comparison which he finds amusing.

I have used thinned rubber cement to seal pouches since 1980, the year
I completed a 1924 single-valve Standard Player Action player piano.  I
was young and I didn't know about sealing the pouches back then.  When
I finished restoring it, I noticed that it would usually read the
bridging in some music rolls and that the repetition was a bit poor.  A
fellow restorer then told me how to seal the pouches using rubber
cement thinned with acetone, then rubbing in a bit of talcum powder so
that they wouldn't be sticky.  That piano has since been sold, but I
still service it, and it is playing perfectly today.  It hasn't read a
bridged note since the pouches were sealed thirty years ago, and it
flies through repetition tests.  The only thing I have had to rebuild
again is the wind motor and to replace the bearings in the pedal
linkages.  That piano has since been passed down to the owner's
children, and I know that it gets a lot of use.

Another player piano that is an interesting oddity restored by me is a
1918 Pratt-Read.  The customer wanted a piano custom-made that would
come on every other hour between 7 am and 7 pm, play a tune, then shut
off.  We delivered that piano in May 2001, and every single day since
then it has played seven songs.  That's about 20,000 plays.  It has
rubber cement sealer on new tan leather pouches, laid as a continuous
strip.  (The original zephyr pouches had been nearly completely eaten
away.) When I opened the windchest of this player two years ago to
repair a ciphering valve, there were absolutely no pouch problems in
evidence.  The action still plays fine today, with excellent
repetition.  I cannot think of a player piano that would be a better
test for rubber cement than this one.

Dozens of player actions I have restored as long as twenty-five years
ago are still playing fine today, and I have never needed to reseal the
pouches.  On my bench is a little brown jar that I've used to thin and
mix "Best-Test" rubber cement for the last twenty years or more.
Cement that has inadvertently dripped onto the outside of the jar over
the years is still as soft, spongy, and gummy as it was when it was
fresh, showing no signs of deterioration and certainly no crumbling.

It has been stated by others that using rubber cement on pouches will
make them thick, stiff, and otherwise useless.  Correctly applied,
rubber cement should never make a pouch thick or stiff.  If they are,
then you are applying the sealer incorrectly and too heavily.

Correctly sealed pouches should be every bit as flexible as unsealed
ones.  Mine have remained so for decades.  Art Reblitz described in the
09.06.14 MMD how to correctly seal a pouch using rubber cement.  Art
and other restorers have timed the repetition of small percussion
actions in Hupfeld and Weber orchestrions operating on both high and
low suction at fourteen times per second twenty years after rubber
cement had been used on the primary pouches.

When certain materials and techniques produce long-lasting, successful
results even though a theory might predict failure, shouldn't we
suspect the theory rather than condemn the results?  I've examined old
pouches that I rubberized years ago and have never seen any evidence of
crystallized, brittle, or otherwise deteriorated rubber cement.  The
sealed pouches were still tight and flexible.

I do not know enough about sealing with alternate materials such as
PVC-E, silicone grease, or RTV silicone.  My purpose here is to share
my experiences with others who may not have realized that good quality
rubber cement is a tested tradition as a pouch sealer and with those
who are against its use because they don't understand the importance of
selecting the best grade of cement and of applying it correctly.

John D. Rutoskey
Automatic Music Machines
Baltimore, MD