Bridge Pin/Epoxy Question

[Tony Court]

----- Original Message -----
From: Farrell <mfarrel2@tampabay.rr.com>
To: <pianotech@ptg.org>
Sent: Sunday, June 11, 2000 1:58 AM
Subject: Re: Bridge Pin/Epoxy Question


> Tell me about tensile strength and CA glue. If CA is as strong or stronger
> than epoxy, I will use it next time. I use it for so many things and just
> LOVE it. What exactly is tensile strength? Is this the type of strength
> measurement we are concerned about for setting pins that are locked into
the
> bridge? How does CA glue compare with good epoxy in this strength
> measurement? I would rather use CA if it is as good. Lemmme no. Thanks
>
> Terry Farrell
> Piano Tuning & Service
> Tampa, Florida
> mfarrel2@tampabay.rr.com
>
> ----- Original Message -----
> From: "Tony Court" <Tony_The_Tuner@nationwideisp.net>
> To: <pianotech@ptg.org>
> Sent: Saturday, June 10, 2000 12:29 PM
> Subject: Re: Bridge Pin/Epoxy Question
>
>
> >
> > ----- Original Message -----
> > From: Farrell <mfarrel2@tampabay.rr.com>
> > To: <pianotech@ptg.org>
> > Sent: Saturday, June 10, 2000 1:03 PM
> > Subject: Bridge Pin/Epoxy Question
> >
> >
> > > Hi List!
> > >
> > > I am restringing my first piano. (yea!!!) Both bridges were in pretty
> good
> >
> > >
> > > My question is: What is the best way to get the epoxy into the bridge
> pin
> > > hole. I have done the bass bridge and used West System epoxy applied
> with
> > >
> > > Terry Farrell
> > > Piano Tuning & Service
> > > Tampa, Florida
> > > mfarrel2@tampabay.rr.com
> > >
> > >
> > I know epoxy is pretty good..........but it ain't half gooey!
> > I have had good results with C.A. glue esp for "fine splits".
> > I use the thin viscosity with an activator. Much easier to clean up
after,
> > and it has phenomenal tensile strength.
>
> >Dear Terry,
           This list is becoming something of a confessional for me!
I first got the idea to use C.A. from a friend who was subscribed to this
list a year or so ago, before I even had a computer. Allegedly there was
much talk of C,A at that time.
          At first, I was a bit skeptical, I think one of the uses at that
time was on  loose tuning pins,(don't quote me here). So I started reading a
bit about it, and have been looking for the books so I could give you some
hard facts in newton metres, and that sort of  thing, but I am unable to
locate the book, or bit of a book at present.......... willl keep looking
though! Bits that I found today did confirm that overall, epoxy is tougher.
But my recollection is that C.A had superior tensile strength, but was a bit
of a let down on shear strength.Tensile strength is what it takes to pull
the joint apart, and shear strength is the force applied sideways to the
joint(e.g twisting).
         I did do some experiments of my own though, and glued two pieces of
maple together......... on application of tensile force, the glue joint did
not break, but the wood separated leaving timber on both sides of the glue.
I also drilled a piece of maple to be a couple of "thou" loose on a tuning
pin, filled with CA and left it over night,(this is the time it takes to
achieve full strength).The following morning, the pin was at first stiff,
but with a little more "shear" force, the CA broke down. This convinced me
that it was not the stuff for loose tuning pins!
         However, Tensile force is the main force in bridge pins, and I have
been indebted to the list for a ripping good idea here! It's a real treat
when out tuning! I do use activator both before on the empty hole, then CA,
reinsert the pin, and a final blast of activator. I leave the string off to
give the glue a chance, but by the time I have "set the scale" I can put the
string on loosley, and tune it when I get there. It seems a good strong
repair, and I know from return visits that it lasts!  Having said all this,
for larger splits, if the piano is not of sufficient quality to warrant a
capping or replacement, I have been known to go back to the epoxy, and
insert screws between the pins to help close the crack!
Hope this hasn't worn your eye balls out, and proves of some use.
There may also be stuff in the list archives, and probably better than this,
judging by the high level of content generally on the list!
Regards
Tony.
> >
>
>