On 7/9/2011 12:48 PM, Existential Angst wrote:
....

Well, this is the crux of my point. If indoor ply WERE sufficiently
"encased" in poly, or some epoxy/plastic coating, COULD it become
weather-proof? And at what cost?
....

The coating _will_ fail at some point owing to the tendency of wood to
move (and it will, though the coating will slow down moisture changes it
will still change) and in the application there's going to be structural
movement as well.

It's hard to imagine HD supplying ANYTHING of quality.
My understanding is that even reputable power tool companies (Bosch et al)
make HD versions.
....

WalMart does that; afaik the BORGs don't; at least for the major
distributors. "House" branded stuff is, of course, different.

As for lumber, Boise-Cascade, Georgia-Pacific, etc., are same products
at wherever they are. As Swing says, what's different is what specific
products they're carrying--much of the box stores' inventory is imported
rather than the name brands so have to be observant. But, that's also
becoming a trend elsewhere as well, sadly. If it has the APA (formerly
American Plywood Assoc., now still use the APA initials but titled the
Engineered Wood Assoc.) grade stamp you can infer the panel from
wherever obtained will meet the standard for that grade (and that there
won't be a great deal of difference in how much "better" one vs another
is at that grade owing to competitive pricing pressure).

It would be useful likely to go review what those stamps on the sheets
actually mean and the definitions behind them.
http://www.apawood.org/level_b.cfm?content=prd_ply_main

Specifically towards your objective might be--

http://www.apawood.org/level_c.cfm?content=pub_ply_libmain

Look for

Plywood in Hostile Environments, Physical Properties and
Applications,Research Report 132. Information provides guidance for
engineers and designers with attention to questions on the physical
properties of plywood and their application in extreme conditions.
Initial research written in 1975, udated in 2008.

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