Quite possibly the key, particularly if it was cool as appears may have
been from followup. TB III is slower-drying than either I or II which
has advantages, but it does require longer before working. I guess I
may have overlooked that detail in initial reading.
Two good possibilities: the wood may be too wet, or
resinous, and the glue isn't 'taking'. Or, your plane
could need sharpening (the pressure on a plane
blade can collapse the little cellulose tubes, and they
won't wick up the glue if they're not open).
Scuff-sanding after flattening the wood will deal with possibility
number two. Epoxy or polyurethane or hide glue
might work better on resinous woods.
Lamination is in some senses an easier gluing task than
making glue-up chunks, because of the large glue area.
The runup to D-day saw a massive effort to glue up plywood
into gliders, and the early batches didn't hold very well. The
trouble was traced to the platen presses (that held the
plies together to make loose bits into solid plywood).
(from _The New Science of Strong Materials_, J. E. Gordon)
"... a proportion of aircraft plywood was ungluable. The joints
in such plywood, made with all due care, looked like
any other joints but had no strength..."
The effect is sometimes called case-hardening, and is
due to microscopic damage that prevents the glue from
penetrating into the wood to make contact with
the subsurface (strong, intact) wood fibers.
Sandpaper is a good treatment for the problem.
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