bridge repair advice

[Carl Meyer]

Realizing that I haven't seen this bridge, I can visualize what you may be
up against.

I question the need to fully separate the broken piece.  I always have
trouble getting it back where it should be.  Wood slivers appear out of
nowhere and mess up the fit.

I'd pull the bridge pins (only the row that is involved) and try to clamp
the piece together.  If it looks okay, then use a thin epoxy (I like Epotec
301, but others are almost as thin), warm the bridge with a hair dryer
before applying, and then clamp for a day or so.  I wouldn't put the pins in
because you won't be able to get them in if the hole is full of epoxy.  And
the clamps will be in the way.  I'd redrill for a fairly loose fit so as not
to split you new job, then put in the pins and add a small drop of epoxy
around the pin after heating it (the pin).  Some have used a soldering iron
held to the pin for just a minute and the epoxy just disappears down the
hole by capillary action.  I haven't actually tried that but since epoxy
gets much thinner  with heat, and heat accelerates the curing  I'm sure it
would work.  I'd only be concerned that the heat shouldn't be excessive.

I don't know what the ultimate cure time is, but some epoxies are specified
as having a cure time of three hours, reaches 90% of its strength after 24
hours and full cure after 3 days.  Some only give a cure time.  Many do not
even specify a hardness.  Epotec 301 has a shore D hardness of 81.  I just
looked at several other spec sheets and no info on hardness.
I'd give it a few days.

Hope it works for you.

Carl Meyer  Assoc. PTG
Santa Clara, California
cmpiano@attbi.com

----- Original Message -----
From: <Tvak@AOL.COM>
To: <pianotech@ptg.org>
Sent: Tuesday, January 01, 2002 7:34 AM
Subject: bridge repair advice


> Next week I'm going to attempt to repair a cracked bass bridge by gluing
it
> back together.  Never having done this before, I'm hoping for some advice
> from those of you who have tried this before.  The bridge, on a 1935
Monarch
> upright, is cracked and separated along the bridge pins.  I plan to
separate
> fully the loose piece, remove the bridge pins, epoxy and clamp the bridge
> together, and re-insert the bridge pins before the glue sets.
>
> Any comments or advice would be greatly appreciated.
>
> Tom Sivak
>
> P.S.
> This is kind of a no lose situation, in that the cost of replacing the
bridge
> is prohibitive to the owner.  (I got estimates from 2 RPTs who encouraged
me
> to try gluing the bridge myself.) They got the piano for free; no pianists
in
> the house;  oldest child is 5, so the piano hopefully was to be used for
> beginning piano lessons in a couple of years.  So if the repair doesn't
work,
> not much is at stake.  It's a good situation for me to venture into the
> unknown.