Adhesives

[Clyde Hollinger]

Friends,

Last week for the first time I used Vagias plastic replacement heads (the first
time I tried this) on an old upright piano that has relatively little value.  It
needed nineteen keytops and should have had a full set of new plastic keytops,
but that didn't seem advisable here and the client didn't want to spend the
money.

Vagias recommends spraying the backs of the keytops with white lacquer, which I
did, then using water-based contact cement.  I was unable to find any, so I used
Weldwood Contact Cement, which is not water-based.  I spread it thinly with a
small (3/8") flat brush on both the keytop and the wood of the key and let it dry
at least ten minutes, then pressed them together.  There was a brush in the
bottle but I was unable to control the amount of glue when I tried to use it.
Again, the plus here is the instant bond and no clamping needed, which is also of
course a minus if you don't get it right the first time.  I was quite satisfied
with this method of gluing the keytops and may continue using it for those
one-at-a-time replacements.

Up to this time I had usually used CA and accelerator, which as Bill mentioned
results in a very weak bond.  Thoughts, anyone?

Clyde Hollinger

Billbrpt@AOL.COM wrote:

>  I wanted to confirm that Susan's discovery in
> which Aliphatic resin glue (sometimes called "yellow glue" or Carpenter's
> Wood Glue, a popular brand name is "Titebond") and CA adhesives can work
> marvelously well in combination with each other.  Using the combination can
> be the best choice in certain circumstances.
>
> I congratulate Susan on this discovery and think it is a good example of the
> type of practical repairs that she is known for describing in detail.  It is
> also a good example of how two substances which any common sense might have
> said were incompatible can actually work together very well.
>
> Gluing back on an ivory which has come loose is a commonly needed repair but
> a simple, clampless method that will really hold and not discolor the ivory
> has been difficult to find.  I had read about this idea and decided to try it
> recently.
>
> I used yellow glue which I normally carry with me but using white glue would
> tend to discolor the translucent ivory even less.  I spread the yellow glue
> on the wood of the key as thinly and evenly as possible and leaving only a
> scant amount at the edge.  I spread the heavier viscosity, "slow" setting CA
> glue sparingly but evenly on the ivory, avoiding the edges.
>
> I put the back edge in place lined it up then pressed it down very firmly
> with my two thumbs and held it for about a half minute.  I sensed that it was
> curing but I did not disturb it    I did try it later and it seemed really
> thoroughly stuck.  I only hope to find this repair holding up years later.
>
> When I have used CA glue alone, it takes too long to set up.  It would need a
> light clamp.  When I have used CA glue with the usual accelerator, it would
> seem to work well but the bond always proved to be very weak.  The ivory
> would always pop off again, sometimes the very next day.  If I would test
> one, I could usually pry it right off.
>
> Susan's suggestions about rubber button gluing make very good sense too.  CA
> glue alone on buttons doesn't set up fast enough.  Using the accelerator is
> difficult (not to mention dangerous and toxic) and it seems that in certain
> cases, it causes the glue to just "fry up" into something that doesn't have
> much holding power.
>
> In this case, the water based white or yellow glue serves as an accelerator
> but a slower one.  I tend to think that the joint is still not fully cured
> until the moisture from the white or yellow glue has been fully absorbed,
> just as is the case when using it the standard way.  But the holding power is
> evident in a nice, comfortable working time rather than a few fleeting
> seconds.
>
> There are other difficult circumstances where this has worked well too.
> Replacing the defective Corfam or other synthetic hammer butt and catcher
> coverings.  I would readily recommend it for quick and sure repairs that
> involve gluing felt to any surface, hammer butt felt replacement for example.
>  Put a dab of slow CA glue on the wood, spread some white or yellow glue on
> the felt, press and hold a few seconds and move on.
>
> I can also see glue combinations working in gap-filling bonds.  Any knowledge
> or experience with this anyone?