Epoxy Reinforcing of Action Parts

[Dave Nereson]

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  ----- Original Message -----=20
  From: Farrell=20
  To: Pianotech=20
  Sent: Saturday, March 29, 2003 2:10 AM
  Subject: Re: Epoxy Reinforcing of Action Parts


  A man after my epoxy reinforced heart! Please explain the items below:
   =20
  ----- Original Message -----=20
  From: "Bill Ballard" <yardbird@vermontel.net>
  To: <pianotech@ptg.org>
  Sent: Saturday, March 29, 2003 12:03 AM
  Subject: Epoxy Reinforcing of Action Parts


  > Dear List,
  >=20
  > i'm working on a 1906 Krakauer 5'10" grand, restringing with =
original=20
  > board and block, new shanks and hammers, and lots of=20
  > refurbish-whatevering in the action. New shanks were a must because=20
  > the wood was fracturing right at the bushings (must be reed maple, =
or=20
  > a let-off rail problem. But I stayed with the original reps.
  >=20
  > It turns out all action parts or what looks like American Beech,=20
  > which after nearly 100 years is quite brittle. (That's why the=20
  > fractured shanks.) The reps did better, although the week spot is =
the=20
  > joint between the jack fly and tender.

  What is the "jack fly"? I imagine the "tender" is the foot part?

  You didn't ask me, but I think I can answer a lot of these -- "Fly" is =
a factory term for the jack.  Yes, the tender is the part that hits the =
regulating button. =20

  > I fond out quickly that I=20
  > wasn't going to be able to cradle the jacks the usual was.=20

  Please explain "cradle the jacks" - I am not familiar with this term.

  I think he's referring to centering the jacks in the repetition lever =
windows (by supporting the wippen from underneath the jack center pin =
"fork" on the side towards which you want to move the jack, and tapping =
the top of the jack with a small hammer to bend the center pin). =20

  > The back=20
  > of the jacks shear off through the CP hole.=20

  Can you clarify this at all - can't quite picture? =20

  But the old wood is too brittle, so instead of the pin bending, the =
jack just splits and shears off at the center pin hole. =20

  > Bending the pin and=20
  > rotating it to vertical isn't going to work. (The bent pin puts a=20
  > gouging stress on the bushing, and shows no sign of ever loosening =
to=20
  > proper friction. Also the orientation of the pin appears not to be=20
  > stable.)

  Again, please explain/clarify. Why are you bending pins? What pin - =
center pin? Rotating to vertical? I don't have a clue as to what you are =
describing.
  Bending pins to center the jack in the rep. lever hole (other =
alternatives are  to install a new jack and hope it's straight, or plug =
the center pin hole with ??? and re-drill it, which I've never tried.  =
Or put in a whole new wippen).  Yes, center pin.  By vertical, I think =
he means centered in the window, as opposed to the jack rubbing on the =
wippen because of a jack center pin hole drilled crooked (or jack =
warpage, or sloppy bushing).

  =20
  > But there are jacks which will need cradle, and no matter how low I=20
  > set the psi on the air nailer, the jacks fracture when I tap them to =

  > cradle them.=20

  Air nailer? To "cradle" a jack? What is this process? Please describe =
in detail.

  Never heard the term, but imagine that "cradling" is centering the =
jacks in the window.  The tops of the jacks are given a light but firm =
tap with a small hammer, just enough to bend the pin and make the jack =
move laterally maybe 1/64 or 1/32, 1/16 max.  "Air nailer" is a bit of =
humor. =20

  > So my next best guess is to impregnate the beech at the=20
  > jack's elbow. That should render the jacks strong enough to take a=20
  > cradling tap.

  You can put epoxy between wooden parts. You can add epoxy to the =
exterior of parts. You can "impregnate" a material with thin epoxy if it =
is quite porous. Beech is pretty darn dense stuff. You will not be able =
to "impregnate" beech with epoxy.

  I'm very curious about the questions above. I look forward to your =
descriptions.

  Terry Farrell

  > Does anybody know how to do this? It's going to be a great piano.=20
  > I've promised to get it back to the  church for Easter.
  >=20
  > Bill Ballard RPT
  > NH Chapter, P.T.G.
  >=20
  > "Lady, this piano is what it is, I am what I am, and you are what =
you are"
  >      ...........From a recurring nightmare.
  > +++++++++++++++++++++
  > _______________________________________________
  > pianotech list info: https://www.moypiano.com/resources/#archives

  As far as impregnating beech with epoxy,  I don't know..... I would go =
for all new jacks.

          David Nereson, RPT
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