Since no one seems to be coming forward and acknowledging these
ridiculous restoration practices posted on here time and time again,
I guess I am going to be the bad guy or good guy depending on how you
comprehend this.

Enough is enough!  I had originally thought that MMD was supposed to
share positive restoration practices and techniques among the community
for the preservation of mechanical music machines.  But, it seems lately
by reading all of these postings that it is doing the exact opposite!

 [ MMDigest doesn't have a panel of experts to review the articles;
 [ we are simply a forum where questions and answers may be posted
 [ to the community.  It is the responsibility of the readers to judge
 [ what's right and what's wrong, and which authors are trustworthy.
 [ -- Robbie

Forgive me for being so forward but it seems like everyone has
forgotten the basics on how mechanical music machines operate due to
the unconventional restoration practices that people follow trying to
cut corners for what I consider temporary fixes.

Recent postings leave the readers with the idea that "sealing pouches"
an acceptable practice.  In reality it is not!  To clarify things,
93-year-old old pouches need to be replaced, not sealed with some
foreign material.

Pouches should _not_ be sealed with any foreign material.  Yes, you
heard right!  If a pouch is leaking bad enough to be inoperable, it
needs to be replaced.

When these machines were designed they took in consideration the length
of the tracker bar tubes, bleed size and the small leakage from the
pouch, etc., to determine the best performance of the pouch itself
(simply said).  There are only a few instances that pouches are sealed,
but again, very few.

This does not mean that all pouches should be sealed.  One of the
main characteristics of a pouch, and to get good performance, is the
"flexibility".  This is why zephyr skin is the chosen pouch material
for certain instruments because of its great flexibility, being that it
is so thin, .002"-.003", and it out-performs a regular leather pouch
and is chosen for its quick response from a smaller signal from the
tracker bar.

You will _never_ match the performance when you coat the pouch surface
with some foreign material.  You alter the flexibility of the pouch
therefore are taking away its performance. Also you have no control on
how the "sealing material" is going to act in different climates nor
can you control how much your putting on the pouch etc. Bottom line is
that you're not accomplishing anything by sealing them in the first
place! You're only creating negative effects.

The small amount of natural bleed that you have passing through a _new_
pouch does not affect the operation of the instrument.  And yes, by
sealing old pouches you can get the piano to play again but will _never_
have the response it should or the reiteration that's necessary for
a good sounding instrument and play all of the notes correctly.

Additionally, I hear of people replacing zephyr skin pouches with
"sealed leather pouches".  This is also a 'No No'.  If an instrument
was designed to use zephyr skin you cannot install regular pouch
leather and expect to get the same performance due to the criteria that
I mentioned earlier.

Some instruments have a low tracker bar signal due to longer supply
tubes, etc.  This is why zephyr skin was the chosen pouch material.
In some cases you won't be able to get the instrument working 100% using
regular leather pouches in these instances -- they simply don't perform
the same.

Zephyr skin is not always airtight, so why don't people seal zephyr
skin?  It's because zephyr is thin and flexible and even with a little
leakage it still operates great.  You would destroy a zephyr skin pouch
by sealing it, because that would make it thicker and harder to flex.

The same goes for a regular pouch.  When you seal a regular pouch
you're making it stiffer and harder to move and less responsive to the
tracker bar signal.

A pouch being 100% sealed is not as important as being flexible.
It can have some leaking although it can't sacrifice the flexing!
I'm explaining this in hoping it will give an understanding on the
characteristics of a pouch and how it can change by coating it with
something.

It's ludicrous to replace a pouch with new leather and then also seal
it -- all that is being accomplished is hampering the operation of the
pouch!

As for older pouches where the leather has worn or dried to the point
of not working, painting them with "gook" is not helping.  This goes
for vacuum and pressure pumps as well; the leather is already
compromised and is still going to deteriorate.

Sealing a new pouch is comparable to restoring a Corvette and taking
the out the V8 engine and replacing it with a 4-cylinder engine.  It
will run but it won't have the same performance as the original.  As
a restorer, it's unconceivable to have access to the pouches and seal
them instead of replacing them.

It's my belief, in most cases, that restored instruments that don't
operate in different climates is not due to the wood expanding and
contracting, like some lead you to believe, but rather due to the
pouches being sealed by a latex or rubber-based compound that normally
hardens, stiffens and or contracts when cold.  It's starting to become
too common to receive restorations that have been newly restored with
the complaint that the instrument does not perform well to find out in
most cases it's because of sealed pouches or inadequate valve travel.

Columbia Organ Supply carries maroon pouch leather that works great for
pouches.  After correctly replacing the pouches "unsealed", at this
point the pouches will be operating at 100%.  From this point forward
if there are any performance issues, you need to take a more in-depth
look at valve travel, etc.

I receive calls all the time on the issue of sealing pouches and
coating the outside of pressure or vacuum pumps, etc.  My only advice
is if you're considering getting a restoration done and the restorer
uses these practices then you need to turn around and run as fast as
you can in the opposite direction.

These musical machines deserve more respect than that, now more than
ever being that the younger generation is oblivious to what a player
piano is.  Extra care needs to be taken in restoring these instruments
to make them perform at their optimum in hoping to re-motivate people
and bring back awareness of mechanical music instruments as it once
was.  This can't be achieved by sub-standard performing instruments.

Hopefully in reading this post it would give the understanding on
why not to seal pouches.  Although I only touched on a few examples,
if anyone has any questions or would like more details I'm always
available to talk shop.  My hours are 7 a.m. to 7 p.m., 7 days a week,
Eastern time.  I will be more than happy to elaborate on this subject
or any other, for that matter.

I'm looking forward to reading the "replies" posting of people trying
to give excuses or to legitimize sealing pouches, pumps, etc.

As I have always said, "It's just as easy to do things the right way as
it is the wrong way."

Musically,
Robert Loeffler - Roberts Musical Restorations
Deland, Florida
http://www.robertsmusicalrestorations.com/