"Labor and frustration doing it a second time will easily make up the difference of dollars spent up front..."
Good point, I'd just as soon not have to tear my bench seat apart again... Can you fill me in on the resin part, though? Available at a local hardware store? Brush on a couple of coats and you're good-to-go? Thanks in advance...
The reason marine ply is so expensive is that not only is it pressure treated, but it uses higher quality wood, so there are no gaps in the plys, which makes it consistant. MDF accomplishes the same thing, but in a different way.
If you use regular ply, I think Roz is telling you to get some resin from West Marine, and coat all the surfaces to keep water from penetrating the wood. Good interior shops will do the same thing to seats- it makes them last longer (prevents dry rot from moisture).
If you want them to last longer than the rest of your boat, use some fiberglass!