Hairline cracks in Treble Bridge

[Andrew and Rebeca Anderson]

It is possible that there is a beating in single strings caused by 
loose bridge pins due to cracking in the bridge.  Put a solid piece 
of metal up against that pin and if it quits, you've found it.  If it 
only loses volume, you're just damping it.  Re-seating the bridge pin 
in epoxy is a good solution for loose bridge pins where there is 
cracking (otherwise going up a size is good too and somewhat less 
permanent).  A quick and easy way I've tried on a cheap old grand is 
to use ultra thin CA glue and let it wick in around the pins and fill 
the cracks.  That has held up well for a year now.
Cracks in the sound-board, loose ribs, loose bridges, case parts, 
loose screws are all possible culprits.  Typically the effect would 
be local to several keys.  The other possibility is sympathetic 
resonances: an unbraided back-scale, loose glass in a picture frame, 
cd music cases nearby etc.

Keep us apprised of developments in the investigation, more detail 
helps to narrow things down to a solution.

All pianos require regular maintenance (more than tuning) to stay in 
good condition.  Certain cheap pianos may have inferior wood and 
other parts utilized in the construction and you should be wary of 
them over longevity issues.  The issue becomes one of cost of 
restoration versus resulting value versus cost of new 
replacement.  There isn't a big market for restored old uprights, it 
is hard to get your investment out of them.  Certain better named 
grands are holding their value better.  People always want a 
"baby-grand" in their living room even if it will only be a 
seldom-used piece of furniture.

Good luck and have fun,
Andrew Anderson