False Beats

[Carl W. Meyer]

I must add my two cents to this thread about ca, epoxy, bridge pins and
tuning pins.
There was a demo I think at the convention at Toronto several years ago. 
It was about filling tuning pin holes (after sealing the bottom) with an
ultra thin epoxy. Epo-tek 301 has a viscosity of 100 centistokes.  That's
thin.  It is also expensive since it was developed for optical use.  Being
thin it will fill all cracks and also find where you didn't seal the bottom
good enough. It cures overnight and cures hard.  I've used it several times
for a complete pin block, drilling the epoxy out and using larger pins.  I
have also plugged several complete blocks.  I made up a drilling machine
with a cheap 5 speed drill press modified to allow full 2 inch stroke with
less than one half turn of the handle.  I've seen these drill presses for
as little as 39 dollars.  I mounted this on a piece white board and slid it
in a tray made with white board spanning across the piano.  It is
reinforced especially on the rear and rests on the rim of the piano at both
ends and slides for and aft on a couple of terry cloth towels.  The drill
assembly slides left to right.  Talcum powder helps.  I then cut my own
plugs with a 3/8 plug cutter and cold gun.  Find just the right size drill
that will give a slip fit.  You may need to use a 6 inch long metric size. 
If the holes in the plate are larger than 3/8 you will have to use a
centering jig for the drill.  I've used epoxy and titebond.  They both seem
to work.  Now redrill with a .250 or .257 and string the piano with 2/0
pins or what ever fits.  BTW, I just use ordinary supply house stock to cut
the plugs.
If you epoxy a pin in a block, don't worry about the pin breaking.  Steel
is harder than any
epoxy.  I've never had a problem.  They always break loose. 

The advantage of ca glue is that it sets up fast.  The disadvantage of ca
glue is that it sets up fast. The thinner ca glue is the faster it sets. 
I've used it for bridge pins, but I find it hard to use and I worry that it
might just seal the top of the hole making further applications impossible.
Due to air at the opening it would tend to set up first there.
I have a bridge to do soon and I plan to use the very thin epoxy and heat
the pins and bridge with a hair drier. Epoxy gets even thinner with heat
and will capillary into the void and allow plenty of time to clean off the
excess.  Epotek 301 cures overnight.  Ca glues fast set up time is great
when you need it, but I like to have plenty of time for other work.

I did find a thin epoxy made by Resin Formulators, but it's not as thin as
the other.  Cheaper though.  I use epoxy and ca ever chance I get.  My
theory is "don't screw it, glue it"!

Carl Meyer  




> [Original Message]
> From: Richard Brekne <Richard.Brekne@grieg.uib.no>
> To: <pianotech@ptg.org>
> Date: 9/21/00 3:45:04 PM
> Subject: Re: False Beats
>
> 
> 
> Newton Hunt wrote:
> 
> > I prefer to CA bridge pins without strings to prevent
> > contact with the string and buildup of CA in places hard to
> > get to.
> 
> I assume you mean in general that removal of bridge pins for application
is
> unneccesary then ?
> 
> >
> > I consider it important that the CA be allowed to work
> > itself down to the bottom of the pin hole and then rise to
> > the top of the bridge thereby filling the hole entirely and
> > holding the full length of the pin in the hole.  If you have
> > a miniscus ring stand for a few seconds without diminishing
> > you know the hole is fully filled then use a tissue corner
> > to wick up the excess.  Otherwise you may not get the full
> > benefit of the CA project.
> 
> Seems like when it dries out it both soaks into the wood and contracts a
> bit. Is this correct ? And if so would a second application do the trick ?
> 
> > On the Nordska I would remove an offending string and see
> > what is under it
> 
> I have read a few posts about what to look for so I am cool on that much..
> Still wondering about the affects of CA glue on the wood of the bridge
> itself. Seems like it soaks in, and this sorta tells me that there might
be
> some effect on the general stiffness / hardness of the top say half a
mill.
> Perhaps this is benificial ?? might help protecting against humidity ??,
> might affect the sound ?? any thoughts Newton ?
> 
> >                 Newton
> 
> --
> Richard Brekne
> RPT, N.P.T.F.
> Bergen, Norway
> 
> 



--- Carl W. Meyer, Santa Clara, Ca.
--- cmpiano@earthlink.net