Need help. (was Sanding Bridge Tops)

[Farrell]

The bridge should be glued to the panel. The screws are there more to hold 
the bridge in place while the glue dries/cures than anything else. When I 
glue a new bridge to a new soundboard I usually remove the screws after the 
glue has dried.

If, as you indicate, the piano has had a long history of bass instability 
(does the pitch go up and down, or just down over time?), you should be able 
to see whether the bass bridge has moved - you should also be able to yank 
on the bass strings at both ends of the bridge and see if the darn thing is 
glued to the panel. Get a good flashlight and a pair of glasses (if needed) 
and closely examine the footprint of the bridge. Yank on that thing - you 
can easily pull on the strings at the bridge hard enough to lift the bridge 
from the panel if it is loose. You can do all that without tearing the thing 
down. If you can see that the bass bridge is indeed loose, then sure, remove 
strings from the bridge, clean glue joint, apply some appropriate adhesive, 
position, and run in some properly sized screws from the back. I'd let the 
glue cure and then go back a re-install the strings and tune (don't take 
strings off tuning pins, just loosen strings and pop them off the hitch 
pins).

Let us know what you shake out of this adventure!

Terry Farrell

> List, I need your help.
> Today I tuned a Young Chang U-121 upright piano, purchased 20-25 years 
> ago.
> I found the bass very out of tune, uneven.
> Customer tells me her previous tuner had problem with bass, but couldn't
> explain why.
> Piano was twice in storage for considerable time, and 2 years ago moved 
> close
> to me, from about 1200 km. away, interstate.
> I closely examined piano, and in trying to tighten bridge screws from the
> back I found them to be stripped. I then explained to the customer that I
> thought this to be the problem and would work out a quote for my next 
> visit.
> Customer has just emailed to say bass out already.
> Can anybody confirm or deny my suspicions here, and advise on a fix for me 
> to
> quote.
> My thought: Loosen bass strings off bridge (do  need to loosen all strings 
> to
> prevent plate cracking), replace bass bridge screws with larger size, try
> injecting glue behind bridge, then replace strings, chip-up, and tune.