Delwin D Fandrich wrote: > That may well be, but it doesn't alter the physics of the situation. > > Regardless of what some of my esteemed colleagues have had to say here, > there is no repair method that has been described here yet that will result > in any lasting improvement in the acoustic performance of soundboard that > has been damaged by compression set. That is, the soundboard panel that was > crowned by what I have labeled the 'compression-crowning' technique. And > that includes most of the soundboards in existence that are exhibiting > multiple cracks and collapsed crown. I've already gone into the reasons why > this is so in a Journal article or two and have no desire to repeat all of > that here. > > Regards, > > Del Actually, I have done three pianos now.. old.. using a method that does indeed reintroduce all kinds of crown into the board... and the results of these three have been very pleasing. So far I have only down this on boards where the ribs are quite easy to loosen. I dont take them off the panel... I bore a whole as close to the center of the rib as I can get, and run a bolt through to hold it temporarilly in place... then I get the rib loose from the panel work some extra glue between them wedge the panel at the rib so that there is a lot of crown and let it dry. Repeat for all the middle ribs. You can see the ends of the ribs being pulled a bit in from the edges of the panel when you do this. Fill the cracks with epoxy when all the ribs that you are going to treat this way are done. Pretty easy to do, creates quite a bit of crown, way more then you can create by shimming... if you can get any at all that way. Tho I have no idea how long this holds up. The first one I did is still doing fine and is 3 years into it.. -- Richard Brekne RPT, N.P.T.F. Bergen, Norway mailto:rbrekne@broadpark.no
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