Pinblock Separation Repair & Pitch Change

[Farrell]

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Good point John. Here in the Sunshine State I have seen quite a few =
termite-infested piano in my few short years in this business. I have =
also ripped apart a couple of them. It seems to be much like rotten wood =
on a boat - if you see a very little evidence of the affliction, safe to =
assume there is about 100 times more damage that you can't see.

Terry Farrell
  ----- Original Message -----=20
  From: John Ross=20
  To: Pianotech=20
  Sent: Tuesday, September 30, 2003 3:58 PM
  Subject: Re: Pinblock Separation Repair & Pitch Change


  Hi Richard,
  At 200 cents flat, I don't drop the pitch.
  I used to use 1/2" carriage bolts, but in a discussion on the list, =
that was considered overkill. So 3/8" will be good enough.
  We don't have a termite problem up here (Canada), but I think I would =
check out the piano further, for a termite problem.
  Someone had brought a piano up from the US, with a termite problem in =
the keys. They appeared to have just a little hole, but in fact had been =
hollowed out in places. Much more damage than indicated.
  Regards,
  John M. Ross
  Windsor, Nova Scotia, Canada
  jrpiano@win.eastlink.ca
    ----- Original Message -----=20
    From: Richard Strang=20
    To: 'Pianotech'=20
    Sent: Thursday, October 30, 2003 5:50 PM
    Subject: RE: Pinblock Separation Repair & Pitch Change


    Thanks for the info, Terry. I have to go make that very repair to a =
piano shortly and was contemplating whether or not to lower the pitch =
first. It this case, the separation is about 1/2"  in the bass and about =
1/4" in the treble. Those pesky little termites are in there, too. I =
think they are causing the problem. They are not in the pinblock, =
though, so the piano is in tune, though 200 cents flat.
       I was also wondering what size bolts to use, 1/4", 3/8"? What do =
you recommend?
    Thanks.

    Richard
      -----Original Message-----
      From: pianotech-bounces@ptg.org =
[mailto:pianotech-bounces@ptg.org]On Behalf Of Farrell
      Sent: Thursday, October 30, 2003 8:09 AM
      To: pianotech@ptg.org
      Subject: Pinblock Separation Repair & Pitch Change


      Differing opinions regarding the benefit of lowering pitch prior =
to drawing a pinblock/backpost separation back together have been =
expressed on this list. I am one that generally feels more comfortable =
lowering pitch. I thought it might be of benefit to put some numbers on =
potential pitch changes.=20

      Yesterday I did one of these repairs on a late model (1980s) =
Baldwin Acrosonic console. It had an approximate 1/4-inch separation =
between the pinblock and the backposts and deadwood back assembly. The =
separation had been "repaired" in the past with something that appeared =
to be silicone bathtub adhesive - surprisingly (?) the separation =
appeared to have widened since the application of the silicone. The =
piano was tuned at that time (and presumably tuned at standard pitch).=20

      Prior to my repair the piano was fairly uniformly 75 cents flat. I =
dropped the pitch to between 200 and 250 cents flat prior to any =
clamping. I yucked in West System epoxy thickened with #403 Microfibers. =
(A fine fiber blend, is used as a thickening additive with =
resin/hardener to create a multi-purpose adhesive, especially for =
bonding wood. Epoxy thickened with microfibers has good gap-filling =
qualities while retaining excellent wetting/penetrating capability.)  I =
drew the gap closed slowly going back and forth among the six 3/4" pipe =
clamps (of which two got bent pretty good!). The separation appeared to =
close very close to 100%.

      I then checked pitch again. Piano was fairly uniformly about 75 =
cents flat. Therefore, it appears that closing the 1/4-inch gap resulted =
in a pitch increase of approximately 150 cents.

      I will be going back to the job on Friday morning to install a few =
through bolts, remove clamps, pitch raise and tune. If there is anyone =
out there that perhaps has not seen this repair done (or whoever for =
whatever reason) wants to see a few photos, I will take them Friday =
morning. Let me know.

      Terry Farrell
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