Greg Martin writes:
Likely the issue was not a plywood (or also know as Plyscore at the time)
but actually an application error... but at the time there was likely little
know of the issue of application or were not properly relayed to the end user.
When you butt plywood edge to edge and don't leave a gap the aforementioned
condition results... apparent delamination at the edge, which could have been
avoided if properly applied. The sheets must be gapped or the top veneer
can't expand and that causes the top veneer to separate from the veneer below and
causes the top veneer to wrinkle or as Tony puts it "curled" or it may check
or as Tony puts it "cracks" These are all installation errors.

I'm sure Greg is right. The PFE documents did refer to "curling, checking and cracking," but as it happens the shop sketch I saw did have about a 1/8 inch gap between the plywood sheets. Is that an inadequate gap, Greg? That gap was in addition to the T-section metal seal strip (with the "leg" of the T down between the sheets).
As for it being an "installation error," I have no doubt that PFE followed the instructions of the Douglas Fir Plywood Association --
whatever they may have been <g>.

Tony Thompson Editor, Signature Press, Berkeley, CA
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