I've seen a lot of postings lately on the "ifs, ands or buts" on the
question of whether or not to use hide glue. I've been experimenting
with it lately, and I guess at this point I'd have to say I'm amazed
with it! Of course, proper procedure must be followed, like any
adhesive, but it's hard to beat this stuff in _brute strength._
I use an antique oak swivel chair in my office (the one I'm sitting on
right now) which had four large stripped-out screw holes for retaining
the legs. Three were actually worn to the point of elongation.
I preheated each of the legs to about 125 degrees F., sized the holes
with diluted hide glue, filled the holes with thick glue and ran the
screws in about 90% of the way. I added toothpicks to fill up the
"worn side" of the elongated holes, before driving the screws in.
I let them sit for about three days, took the screws back out and
cleaned the excess glue off. I reassembled it today, and was able to
fully torque those screws -- if I tighten them any more, I'll probably
damage the screwdriver and (or) the screw heads.
This stuff is hard to beat. I've used epoxy for this purpose before
and it didn't perform nearly as well, and I would have had to use a
"mold release agent" on the screws to keep them from being glued in.
Okay, I've been talking about a chair, which is kind of "out of the
realm" of automatic musical instruments, but surely it's the glue of
choice for that simply because of it's ease of removal. I've used
PVC-E glues for player piano work before and, while it might be good
for gluing coverings on pneumatics and pouches, it's not even
appropriate for wood-to-wood joints because of the drying process.
It warps the wood in the process, and actually works against itself.
In numerous articles by Craig Brougher, and in his "Orchestrion
Builder's Manual", he speaks of the downside to water-based evaporation
type glues, in that when they dry they form a "lacy" pattern that can
be seen if you pull the joint back apart, and I've seen this as well.
Hide glue simply doesn't do that at all, and it's much stronger because
of its chemical bond.
Of course, glue quality can be a factor as well. The glue I'm using
now was formulated by Craig Brougher and purchased through John Tuttle
at http://www.playercare.com/ I highly recommend it!