Epoxying tenor bridge

[j. kehe]

----------

> Date:          Fri, 15 Nov 1996 15:27:36 -0500
> From:          SGrossner@aol.com
> Subject:       Epoxying tenor bridge
>
> I am rebuilding a Starck grand, not a
> great piano, but the long treble/tenor bridge has myriad cracks and loose
> pins. In the past, I would take the pins out, squirt marine epoxy in
there
> and hammer in the pins, wiping away the excess.

If the cracks are not too wide and the pins not wobbly, this is a viable
alternative for a customer who wants to keep costs down. I would (1) insert
*new* pins before the epoxy sets up and (2) would *not*  file the b.p. tops
and (3) would brush the notches lightly with a brush slightly wetted with
lacquer thinner to clean up.

>This worked pretty well for
> bass bridges, but I am concerned about compromising the surface of the
treble
> bridge with residue-affecting the tone, etc.

Cleaning up with the lacquer thinner should solve that problem.

>A rebuilder in Chicago here once
> suggested damming off the entire bridge say with duct tape and literally
> submersing the entire affair in epoxy (I am using Abatron wood
consolidant
> from Milwaukee)
<snip>

Can't speak for others but this sounds like a terrible mess!

<snip>

> Should I
> spray a release on the bridge such as teflon?

Spraying a release would also penetrate into the cracks and cause problems
with the epoxy fill.

> The alternative is to take out 360 odd bridge pins and put em
> back in with dubious results. Usually the epoxy finds some subterranean
> cavity to fill and retreats from the bridge surface before it hardens.

But thats exactly what you want it to do.  If you use a slow set epoxy with
at least a 30-60 minute pot life, keep filling up those holes (do a section
of say 20 unis. at a time) with the stuff and then tap in the new pins. I
use a scrap piece of bass string leader to dab in the epoxy. Clean up the
squeeze-out with the brush/lacquer thinner. If there are any dubious
results, it's because the bridge should not have been epoxied in the first
place. Generally my rule of thumb is, if I can stare down into the crack or
pull the pins out by hand, I recap instead of repair.


Kind regards,

jack kehe
chicago

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