Old Hamilton studio bridge cracks

[Robert Goodale]

Dan Eumurian wrote:

> List,
>
> I'm not picking on anybody, but I've run across four Hamilton studios
> dating back a couple of decades or so with wedge cracks throughout the
> long bridge, and buzzing strings. None of the four had Dampp-Chaser
> systems when I first saw them, although I installed a system in one of
> the three, which was in a church.
>
> In the church piano and in one of the home pianos, I lowered tension,
> repositioned stagger pins, treated with CA glue, raised pitch after a
> few days, and tuned, but in both cases the problem came back.
>
> I didn't know at the time about using tape to cover the center of the
> bridge, so I got some glue on it, which I tried to clean off. Is it my
> technique, or was there a period of time when this problem was common?
> Should I recap, replace, or advise the church to look for a different
> instrument? Thanks for any ideas.

Dan,

I have run across this problem many times, often on Hamiltons.  Typically
I remove all of the strings in the effected area.  This doesn't mean you
have to de-string, just loosen, remove the strings from the hitch pins,
and set them aside.  If we are talking about the bass bridge string a wire
through the hitch loops to help keep them in order.

Next pull all of the pins.  I like to replace the pins when I do this just
because they are cheep, easy, and makes me feel better about the repair,
so I throw the old ones away.   When replacing always use the same size
that you remove.  NEVER use the next size larger thinking it will make a
tighter fit.  Unlike tuning pins the difference between bridge pin sizes
is substantial.  It will split the bridge further and give you all kinds
of interesting false beats to swear over.  Also- get the full 1" long
pins, not the virtually useless short ones.  PianoTek has some I really
like.  If the bridge is in good enough shape that you can see where the
pins should be you might want to make a pattern.  If it is exceptionally
bad, however, best guess will probably suffice for a Hamilton.

Next fill the voids with epoxy.  I highly recommend West System,
(available at PianoTek).  Be sure to get the 24 hour cure, not the
quick-set stuff.  The viscosity of this is perfect because of its thinness
which allows it to penetrate deep into the damaged wood.  If necessary
mask around the bridge so that it doesn't make a mess.  To completely fill
the voids you may need to do this two or three times.  If the bridge is
split so bad that it has spread out sideways then you can use clamps to
hold it together during the process.

Assuming there is excess epoxy everywhere you will want to use file and
whatever else to shape it back to the proper dimensions.  You will need to
re-drill the pin holes.  Work slow, the heat from the drill will soften
the epoxy and clog the bit.  Be certain to drill the pins at the correct
angle or you will be cussing at yourself the entire time you are redoing
the job.  Next re-dag the bridge top surface.  I prefer to use gray liquid
teflon.  After brushing it on use a bass hammer to burnish it to a nice
polished texture.  Next you will need to re-notch the bridge with a sharp
chisel.  Recall that the notch should start at exactly half way through
the pin hole location.  Finally, grind the pins down to the proper height
to match the rest.  If I was doing a complete piano I would use a belt
sander but if you are just doing a section then use a file.

String'er up and and you should be in business!

Good luck,

Rob Goodale, RPT