[pianotech] Pinblock Cracks, CA or Epoxy

Joseph Garrett joegarrett at earthlink.net
Mon Nov 5 09:44:55 MST 2012


David B. Said: 
"Thanks for all your responses folks. 
The client at first sent me the photo, and I did think that as sometimes 
happens, it would only be a spliit in the birdseye veneer, and indeed I 
emailed that thought to him. 
However, when I got there, using a fine broach as a 'depth guage', I 
found that the splits had depth varying from about a quarter of an inch, 
to three eigths of an inch. 
The piano had been in exactly the damp-to-dry scenario. The house was 
unoccupied and damp for years, then everything including the piano, put 
in storage while the house was gutted and renovated (with electric 
underfloor heating), then brought back into a warm dry house. 
Actually, the tuning pins were fine, in terms of tightness, although, as 
you may see from a close look at the pic, oblong. Yukl yuk yuk. The 
piano was about 400 cents low in some parts, and 200 in the bass, and we 
settled on tuning it at 300 cents low to see how it went. It hurt me 
to pull the bass down, but it seemed the best option.
 I did feel that with the epoxy, it might be difficult to get good 
penetration, and that this might be easier with CA, but I wondered if 
epoxy might be stronger at holding things together. 
I've explained to the client that we will need to keep an eye on how the 
piano performs over the months, in its now warm and dry environment.
 A photo is attached. Plus you can see photos of part of the journey to 
his house on my Blog at pianopinions.tumblr.com
 
Best regards,"
 
David,
I think you are being Ultra conservative with your approach. What you need
to know is: 1. those pianos have a Low Tension Scale to begin with, (by
design) 2. The piano string/pinblock system functions at it's best, AT it's
designed tension. i.e. there will be better stability and tunability at the
designed tension. Leaving or puting the piano 300 cents low is a mistake,
imo. 
If it were me, I would have raised the pitch to 100 cents flat in the
initial session, to see how the structure took it all. Then, have at it
again, within 3 months. At that point I would attempt to tune it at it's
Designed Pitch, A=435cps. I doubt that anything bad would occur using this
process. IF there were problems, then I would attempt to fix them. (i.e. If
it ain't busted, don't try to fix it!<G>)
 Since I've had extensive experience with these pianos, I feel confident
that this is the best approach. Also, it is my opinion, you have not done
any harm by lowering the bass and raising the treble. At this juncture, you
have merely broken the crusty corrosion that I've found on most, at the
string termini.<G>
BTW, Epoxy, not only has greater "strength" than CA, it will, somewhat,
bond with the glue existing in the joints of the "Pinblock", better than CA
would. At least this is what I have experienced with usage of both. Neither
is the be all for every application, as some would like us to believe.<G>
Best Regards,
Joe

Joe Garrett, R.P.T.
Captain of the Tool Police
Squares R I



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