Restoring crown in old soundboards

[Alan Forsyth]

While the list is discussing soundboard crown at the moment, I thought I
might mention that a piano dealer sent a 100 year old Steinway grand with a
badly cracked soundboard back to the factory in Hamburg for restoration.
Well, £8000 ($12k) and 3 months later it came back sounding perfect. To my
surprise, I was told that, the factory did not install a new soundboard but
instead repaired the original by shimming, i.e. filing in the cracks with
those V shaped wedge fillets.
 When I was at piano college we were told that this is a method used to
restore crown "in situ" as it were. The theory, I suppose, is that if you
wedge more material into the panels, it will force the panels to bow or bend
back into shape. I have not yet had the opportunity to put this to the test,
but have any of you tried this method or think it feasible.

Regards
Alan Forsyth
Edinburgh
   "Madam, all pianos sound horrible, but if you play music on them they
sound very nice!"  (from my forthcoming book, "A Day In The Life Of a Piano
Tuner" by yours truly)