On Sunday, April 8, 2018 at 2:21:04 PM UTC-4, wrote:
On Thursday, July 7, 2011 at 3:52:24 PM UTC-5, Existential Angst wrote:
Awl --

I'm looking to make a 4 ft x 6 ft base for some apparatus, out of 1/2"
plywood, for outdoor use.
It works well indoors, but I'm wondering if I can make it *truly* waterproof
for outdoor use, with enough coats of poly, epoxy, or some clear plastic
coating-type finishes I've seen.

Not that familiar with wood/coatings, beyond having done my floors with a
water-based poly+catalyst, with mixed results.

Also, I know there's HD 1/2 plywood, which you can break across your knee,
and there is real 1/2 ply, from a lumber yard. Are there even
harder/stiffer grades? I'm not necessarily looking for furniture-grade
plywood, but maybe that is indeed the stiffest. Cost, bang for the buck is
a factor.
Maybe other "engineered products"?

Appreciate all input.
--
EA

First off, working with plywood needs to consider more factors than working with 100% mill type lumber woods.

First off, working with posts that are 6 years old needs to consider more
factors than working with posts that are current and may actually still
be monitored by the original poster.