I must say that I am pleasantly surprised at the number of responses
to my article "Cabinet Maker Hates Hot Glue".  (It generated almost
as many responses as phonograph turntable speeds!)

The subject of gluing has so many facts, figures, opinions and errors
that it seems a lifetime is not enough to master it.  It reminds me a
bit of the old parable of the Blind Men And The Elephant where everyone
has a different opinion.

I am surprised to read from Dan Wilson that he heard hot glue became
"a safe thing to use" in the 1930's because of the thermostatically
controlled heater.  I always thought that the 1930's was the virtual
end of hot glue in industry.  I believe there is plenty of literature
about grades of glue and methods of use that were available in the
1800s.  I have heard that furniture found in Egyptian tombs was
assembled with hot glue (and it is still going strong!)

Let me express some of my own personal feelings on glue:

White glue actually has a use or two.  Under some conditions, layers
of wood (like veneer) that were glued together begin to separate.  If
you thin the white glue with a little water, you can begin to inject it
between the layers.  At this point, keep squeezing the layers together
and then releasing them.

As the wood flexes back and forth, capillary action takes over and
draws the glue in deeper than you could ever get otherwise.  Keep
applying more glue and keep squeezing-releasing until you are satisfied
that no more glue can be absorbed.  At this point, clamp it overnight
under wax paper and you have a great repair.  Veneer is usually meant
to be permanent anyway, so all is well.

It is my understanding that yellow carpenter glue does not take well
to thinning, and hot glue would be a nightmare here.  Franklin Hide
Glue (with urea) might be able to be thinned down, but I have not
tried it.

On the other hand, white glue is worst glue on earth for repairing
bushings.  Hot glue has a fast tack and an easy removal, and this is
why it should be used here.  If you use white glue on bushings, like
piano key bushings, there is no tackiness and the cauls have to be
left in the keys overnight to keep the bushing cloth against the wood.
Now the white glue soaks through the bushing cloth and gives you hard
bushings, and you are worse off than when you started.

And the nightmare is only beginning.  There is no easy way to remove
this mess, and hours will be spent cutting and picking the mess out of
the keys.  Some wood is bound to be lost, so bushing with hot glue now
will not help you; you must repair the keys first.  See what I mean?
So when I hear of two people arguing if white glue is good or not,
I wish them luck.  If you are not going to be very specific, you are
wasting your time -- and everybody else's.

And if the field were not complicated enough, new materials are
appearing all the time.  The relatively new cyanoacrylic or "crazy
glue" materials can be a blessing or a curse.

Incidentally, here is a tip, which I may have got from Craig Brougher's
fine book on Orchestrion Building: These crazy glues can be used with a
second chemical to speed the drying.  It is tricky to use this, and the
suggestion is to soak a tiny sponge in this chemical, call the
"accelerator".  Keep this small sponge in a plastic squeeze bottle.

After applying the crazy glue, the squeeze bottle sends vapors of
the chemical out, rather than spraying a liquid.  It gives you more
control.  I haven't used this yet, but it sounds great.  I use crazy
glues to harden screw holes in wood so the screw doesn't strip as
easily.

I also agree that the MMD Archives are an absolutely priceless mother
lode of information, and am curious why more people do not use it.
Here is a suggestion (easier said than done) for this topic.  Somebody
(not me) should make up a computerized, cross-indexed glue guide.

Obviously, it cannot be all-inclusive, but the important thing is
that it is a central source, and it can grow over time.  If someone
looks up "Valve Blocks" or "Piano Hammers" they will see why hot glue
is a necessity, and will be told why white glue is an abomination.
On the other hand, if someone looks up "White Glue" or "Contact Cement"
they will see when it is acceptable and when it isn't.

I do not expect this guide to change things overnight, and the good
craftspeople will always have taken it upon themselves to educate
themselves.  Still, I think there is a use for this type of list.
We all started off wet behind the ears, and if we can prevent some
eager newcomer from getting yellow glue all over Grandpa's nickelodeon,
then it will have been worth it.

Randolph Herr