Formaldehyde glue

[Clyde Hollinger]

Ken,

I can't answer your questions about the formaldehyde glue.

For a 1/4" separation the most important thing is to stabilize the
separation so it doesn't get worse.  With this crumbly glue you talk about,
I would probably tell the client that doing the job right will be very
expensive, and give a quote for replacing the pinblock.  I would also say
that I am relatively confident that the piano can be repaired for a lot less
than that, but unfortunately I can't give a guarantee.  If he's willing to
take the risk, pull the crack together with clamps the best you can, fill it
with epoxy, and bolt it together good.

NOTE:  Whenever I don't guarantee my work -- for example, a soda straw
repair of a hammer shank for a client who won't pay the labor for a new
shank on a wornout piano -- I inform the client orally and also put it in
writing on the invoice.  I have to cover my own backside.

Regards, Clyde

Kenneth Zahringer wrote:

> I was recently called to check out a piano that another technician had
> declared untuneable.  Well, he was right.  The pinblock had completely
> separated from the back beam - end to end, top to bottom.  I looked in
> the gap and both surfaces were covered with what looked like a flocking
> of glue.  I scraped some of the glue from the underside of the block, in
> back, and it crumbled in my fingers - full of air bubbles, I think.
> Once it crumbled, though, the remaining granules were rock hard.  The
> manufacturer said at the time this piano was built they were using
> formaldehyde glue in this joint.  The warranty expired some years ago,
> so it's up to the owner and me to fix it.  I would like to do this
> without disassembling it, replacing the block, and restringing it.  It's
> not that old and the pins are still fairly tight.
>
> My problem is that old glue.  I know there is no way I could clean all,
> or even most, of it out of a gap that's barely 1/4 inch wide.  And the
> granule are so hard I'm sure they would prevent the two surfaces from
> being clamped together effectively.  Does anyone know of a way to soften
> or dissolve formaldehyde glue?  Can it be "reactivated"?  If it were
> softened or partly liquefied, would it interfere chemically with other
> glue, like Titebond?  Based on what little I know about formaldehyde
> glue, I'm not sure I want to use it in my shop.
>
> Ken Zahringer, RPT
> Columbia, MO