Formaldehyde glue

[Delwin D Fandrich]

----- Original Message -----
From: <Wimblees@AOL.COM>
To: <pianotech@ptg.org>
Sent: October 29, 2000 7:39 PM
Subject: Re: Formaldehyde glue


> In a message dated 10/29/00 8:15:04 PM Central Standard Time,
> zahrprice@earthlink.net writes:
>
> << 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
>   >>
>
>
> From what I remember, formaldehyde glue is "nuked" to cure. They heated it
> with microwaves. I guess that is the way it has to be dissolved too. It
would
> appear that this piano might be a lost cause.
>
> Willem

Ken & Willem,

Half of the pianos that have been discussed over the past however-many years
with pinblock/back separations had been assembled using phenol-formaldehyde
glue.

No, it cannot be 're-activated.'  Not even with 'microwaves.'  (Actually, it
is usually somewhat lower in frequency than microwave.)

But, if you follow the most common instructions -- fill the crack with epoxy
(I prefer one of the main-line epoxies with just a bit of ground cotton
fiber to add some cohesive strength, you still want it reasonably pourable),
pull the thing together as best you can with clamps and install
through-bolts (making sure that the through-bolts go through the vertical
back posts) -- you should have not further problems from the piano.  At
least not from that part of it.

Del