Hi y'all,  I have perplexing problems with rebuilding a "rebuilt" 1938
Spinet Ampico.  The piano was restrung with new hammers maybe eight
years ago.  A friend bought it from the Cleveland area and brought it
back to Buffalo.  When a roll was put in, it would rush through sections
where there were lots of notes being played, but weakly played other
sections.

The previous rebuilder popped all the pneumatics off the stack and
removed the pneumatic cloth off of three sides, leaving the hinge side
with original cloth "glued" in place.  He used spray glue to reattach
a strange material that inevitably didn't adhere well to the wood.

The hinge end had two beads of some kind of cement to remove any
leakage where the two types of cloth met.  He put small pieces of
Polylon over the original black pneumatic cloth.  The pneumatics were
glued back on to the tiers with a clear "plastic" glue that hardened
to rock consistency.

The valve blocks were taken apart and valve facings were replaced
with a gasket type of leather, not cabretta!  I replaced all the valve
facings and gave them .032" travel.  A heavy, harder leather was used
to seal the valve blocks.  I changed that leather to cork gaskets.

The expression units had bad valve facings in them and I replaced them
with appropriate material.  The expression pneumatics seem to have been
done well so I didn't touch them.  The crescendo, sustain and soft
pedal pneumatics seem to have been done correctly.  The pump has been
recovered with a material too light for the job at hand.  I temporarily
put a heavier material over the creases to seal any leaking joints.

The exterior flap valves on the pump had a leather which looked like
miniature shag carpeting.  I removed that and put on a decent flap
leather.  (By the way, he pulled off the metal rods which go lengthways
under the flat valve material.)  The interior flap valves seem to have
been untouched.

The pump, which is a "grasshopper-cricket" type of pump had the same
treatment as the pneumatics: new material on three sides and the fourth
side had a new cloth added to the hinge, with a seam of glue at the
edges.

With a gauge on the pump I can get a pattern of 60-60-65-70 inches of
vacuum produced by the pump.  With the Tempo at zero and 2,4 & 6 open
on both sides I can get close to 20 inches of vacuum at the stack with
blank paper over the tracker bar.  Once notes start playing the vacuum
drops to 8" to 15" of vacuum.  I have been contemplating the addition
of an external reservoir on the back of the piano.

The piano plays quietly and plays all notes (but the treble end hammers
need hardening).  I have also been thinking about biting the bullet and
rebuilding the pump with correct cloth and check the internal flap
valves.

Should the travel in the valve blocks be reduced?  Where is that 40" of
vacuum disappearing to?  I hear no audible leaks from the stack.  There
was a leak in the treble expression unit where the rear mounting screw
was leaking vacuum outside through the hole.  That should be sealed
with sealer and leather gaskets at each end of the hole.  Any thoughts?

Thanks very much for any input!

Best wishes,
Mike Walter
mikew_14086@yahoo.com.geentroep [delete ".geentroep" to reply]