Join Date: Oct 2000
Location: Portland, OR
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Re: Is Marine plywood a must?
Historical note: back in the 60's, the cost and construction of plywood sort of rose based on cost of glue and integrity of the layers.
Basic ply had voids and non-waterproof glue. A step up got you plugged (patches) on the voids. Next level was less voids and waterproof glue. The best product was better veneers with few plugs and waterproof glue, and was called "marine plywood". Cost more, but both the labor in added inspection of the veneers and cost of glue went up, too.
Sometime in the last 20 years (?) most plywood was laid up with waterproof glue, with the interior layers and their integrity adding or lowering the cost.
Then there are products that use just fibers and pieces of fiberous wood... and cost less.
Now we live in a world of "engineered" wood-derived products and prices range over quite a long scale, depending on required strength.
FWIW, if the wood in any project is just there for "coring", you can use less expansive ply and lay some glass and resin on both sides and encapsulate it.
Example --- for a couple of decades I have used honeycomb panels for all interior projects, joined with epoxy and glass where needed. (I salted away a quantity of this "scrap" paneling, in a lot of odd sizes, before the Boeing Surplus Store closed up. They used to dispose of it for fifty cents a pound..... Oh My.
Sure do miss that place!
1988 Olson 34, by Ericson Yachts.
Sail # 28400
Betamarine 25 (new 2018)
RCYC, Portland, Oregon
Last edited by olson34; 07-26-2019 at 12:34 PM.