Mike Knudsen asked, "How old is plywood?"

This will be difficult to answer without strictly defining "plywood".
Is veneer over a lumber-core considered plywood?  Or do we speak only of
built-up veneers which have the grain set in opposition.  I will assume
the latter, and run with it:

The answer to "how old is plywood" may actually lie in antiquity, because
even Bronze Age societies used overlay techniques on a wooden form.  And
splitting wood has been a problem all along!

I possess a Billhorn folding reed organ which was built in the 1890s and
is made to a large degree with built-up veneers.  I cannot say exactly
when reed organ builders began to use plywood (equal thickness veneers,
with grains crossing), but I have not found any in the organs prior to
circa 1875.

> Also, how do folks feel about using plywood in "authentic" restorations?

In my humble opinion, if the original was not plywood, then plywood
disqualifies as "authentic".

> .... [plywood] has its own problems with splitting and delaminating,
> but probably takes end-grain screws and nails better.  And it shouldn't
> warp.

I can agree with Mike's statement, but only because plywood is slightly
better for end-grain fastening than solid wood -- and that's if you drill
correct screw holes!  There are techniques and hardware for getting
around this problem.

Plywood offers significant advantages over solid wood, _when the
application is appropriate_ .  Plywood is more resistant to some kinds
of warping, but you must use it intelligently.  For greatest stability,
the finish used on one side should be applied to the other.  Else the
finished side shrinks/expands at a different rate than the unfinished,
so it warps.

If you want to experiment with modern materials that resist warp and can
be machined and carved in ways plywood cannot, try MDF (Medium Density
Fiberboard), which is amazingly dense and has no grain.  It takes paint
or veneers nicely.  It's also extremely flat, so layers in say, a pipe
toeboard/pipe channels system seat so tightly, you don't need a gasket.

Regards,
Robert Linnstaedt