Richard, I am not quite sure what you are trying to say that you did! Was it the expantion of the epoxy in the ribs that gave more crown? If so a very interesting consept. To drill holes along the ribs to gain more crown. Joe Goss ----- Original Message ----- From: Richard Brekne <richardb@c2i.net> To: <pianotech@ptg.org> Sent: Sunday, December 26, 1999 3:03 AM Subject: A nice suprise fix > List: > > I thought I'd put this in the mix just for kicks and any comment > > I just "fixed" up an old german make (Krautzer or something like that, I can get > you the correct name and number if you like). This is typically the kind of piano > I just throw away, as its condition was just absolutely horrible. But > circumstances surrounding the ownership and some close personal relationships > convinced me to "paste" this thing back together. It is used in a home for the > retarded that has no chance of buying anything else, or even paying for the > repair.. > > The soundboard was extremely cracked up, ribs mostly pulled away, and this > horrendous warpage along one side of the worst crack. In addition someone at > sometime had tried to repair this board by screwing (countem) 149 screws through > the soundboard and into the ribs. Needless to say this was a miserable failure. > There was no downbearing anywhere along either bridge, and the board had no crown > left (perhaps even a bit of negative crown in the lower tenor area, hard to tell > because of the condition of the board) > > Anyways... I told these folks what I think of such pianos, and that all I would > do was to reattach the ribs, and fill the cracks with epoxy to stop all the > buzzing /distortion, but that they should not expect any kind of good quality > sound. It would be made functional and nothing more. > > I pulled the plate and removed all the strings, bored through the panel on each > side of all cracks along the ribs and forced the board back together glueing > with epoxy (west system epoxy). Along the crack that was curled badly, the panel > just cracked up some more, so those and all other cracks were filled with the > same epoxy. > > The interesting part tho has to do with how I reattached the ribs. There was > little holding any of them in place. I started at the top (treble) side of each > rib, wedged the panel slightly outwards before tightening the bolts and glueing, > then moved basswards. I noticed almost immediatly that each rib was being > "pulled" a bit towards the treble side. Each of the 149 screw holes were filled > with epoxy, and then tight dowels pushed into the holes to force as much epoxy > into any hidden loose spots between the ribs and the panel. When I got done with > the whole thing the lower end of each rib had moved quite a bit towards the > treble. The rib across the bass bridge moved actually about an inch. A couple > days of curring and I removed all wedges and measured the crown in the board. > Whoooaaa... tons of it. A string across the panel backside showed 2 mm in the > middle, and whats more it all looked really evenly graduated where ever I > stretched a line. After restringing there was just a bit of downbearing and > fairly uniform along the whole panel. (the lowest bass and lowest treble had the > least bearing, highest treble just a bit more, and the areas inbetween the most, > even through the treble / tenor break) > > Its up to pitch now, and sounds absolutely great. I couldnt believe the sound > actually. pretty clean, not a hint of that "old beat to shi... soundboard" sound. > Really strong, especially the bass has that nice big boomy sound. Nice crisp > high end, and no really bad spots or uneven spots anywhere. > > I suppose I will have to wait to see how long this pasting will hold up, but in > anycase it was the nicest suprise I have had in a long time. It does seem to > point at a method of re-introducing crown to an old panel tho, and I got another > beater with a particularily nice case that I can experiment on. <grin> > > Richard Brekne > I.C.P.T.G. N.P.T.F. > Bergen, Norway > > > > >
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