question about deck work

[1962 31]

yesterday i cut all the 3/4 marine plywood for the deck i want to completely glass both sides with west system epoxy resin and light weight fiberglass mat. my question is do i have to worry about the sheet warping at all while it is drying? thanks in advance
Tom

[CaptPatrick]

Tom,

3/4" ply is pretty stable stuff & you should have no problem with warping during the epoxy glassing process.

The main warp potential can come from shrinkage of the epoxy as it cures. If you have a significantly different thickness of epoxy/glass between the two side of the plywood, the tendency will be for the heavier glassed side to cup, creating a convex crown to the lighter side.

If you keep the two sides equal, you'll have no more warping than may already exist before glassing.

The edges of the ply should also be glassed, not just encapsulated. The principle avenue for moisture absorption is the end grain, (edges), of the ply. Resins have almost no strength without the fiberglass to reinforce them. Simply encapsulating will eventually lead to cracking of the cured resin & moisture intrusion. Round over your sharp corners so that the glass is actually overlapped at those points...

Br,

Patrick

[1962 31]

thank you exactly what i needed to know now off to work