[pianotech] epoxy problems

[Douglas Gregg]

I have had an avid interest in adhesives since I did a term paper on
them in advanced chemistry bach in 1962. Jeez that was a long time
ago.  My wife calls my passion the "adhesive of the month club". I
have a few favorites.

 West System just came out with a very strong yet flexible epoxy that
their techs could not even believe. It is G-Flex. It is a bit slow
setting but great for things like rib repairs to soundboard or moving
wooden parts under high stress. Usually strong adhesives that set slow
and are strong are also brittle. Not this one. It has good penetration
too.

 As stated before about the green piano bridge, I like JB Weld and
Marine Tex black for high compression resistance, machinability and
heat resistance up to 240degrees F. It can be used to repair an
autoclave door flange. Very little creep but it is a bit thick and
won't penetrate too well unless warmed up.

I use Weldbond for all kinds of things. I carry  a small bottle of it
in my tuning kit.  It looks and handles  like Elmers white glue but is
much, much better. It was designed to glue tiles on the space shuttle.
It is great for wood. You can even glue wood to metal, glass,
concrete, and plaster with it- or any of them to each other. It dries
clear.

An elastomeric that will stick to nearly everything including those
molded high density polyethylene kids toys that resist any other glue
including epoxy. It is the Welder. It works like a contact adhesive
(rubber cement or Goop)  but is  stronger and will not yellow or
become brittle like Goop. Great for gluing felt and leather. Fix your
shoes with it too.

Another that is a bit hard to find is a CA glue called PascoFix glue.
It is anaerobic ultra pure medical grade CA glue. It can be used in
dentistry. Anaerobic means that it sets quickly even without oxygen
present, like tight fits, under water, inside the body, etc. It can
glue where some CA glues fail miserably. It can even be used to glue
rubber patches on tires. There is an accessory Pasco filling powder
that can be piled up on a part to fill in a missing portion like a
broken plastic part and then be polymerized with a drop of  the
PascoFix. This polymerized powder (now a very hard solid) is very
strong, can then be machined back to any shape and be as strong or
stronger than the original part. I think the powder is acrylic powder.
 This stuff is amazing. It has saved me a few times by reproducing a
plastic part with missing portions that was otherwise unavailable.

Happy gluing.

Douglas Gregg BS, DVM, MEd, PhD, over-educated nerd
Classic Piano Doc
Southold, NY