Stan wrote:
Boards are 1-1/8" thick.

Glue is Titebond III.

Current measurement in
my shop is ~40% Rh and in the winter it was in the 20s but it has gone
higher in the past week.

Wood was supposedly kiln dried but probably
sat in an open door barn for years. It sat in my shop for months
before planing and sat there for months after being planed and jointed
before I glued it up.

I noticed a very slight crack weeks ago but just
noticed the big ones yesterday, along with the severe curling. It is
just sitting out on my work bench.
Stan


Stan:

Hope you see George's answer by now.

Also - I think you are saying that you glued it and it sat for "quite a
while"???

BTW -- Seasonal change is what you mean. (Climate is long term... :-) ) FWIW

After you look at George's response think about.... Is it possible that
you had a number of factors at work?

A) it was "too cold"
b) Clamped too hard (Just tight enough to squeeze excess glue is best
b) The glue was old or bad or maybe not quite as good as possible...
c) A quick moisture change along with the above

It seems like "too much" of a failure considering that you tried to take
reasonable care.

Maybe your timing on the gluing was just terrible -- i.e. way too cold
--- and then the seasonal change hit and you got too much stress.

Also -- If I cannot immediately smooth and finish these types of pieces,
I have taken to sealing the wood ends quickly after gluing up long
pieces -- just to make sure that "rapid" humidity changes don't cause
problems.



--
Will
Occasional Techno-geek