: There's no such thing as non-waterproof plywood any more.

: Quite a few years ago that stopped. Waterproof glues and no more
: money than non-waterproof glues and the plywood manufactures
: have been using waterproof glues for over 15 years.
: however, what you get with marine grade plywood is no voids. high
: quality laminations and materials and perhaps better
: manufacturing and nicer face skins.

Jay:

When I did my initial testing on the Russian Birch, I threw in a piece of, what I assumed, was exterior grade fir plywood. After one hour boiling in the pot, the plies basically fell apart in my hands. Perhpas the plies just soaked up to much water, I don't know.

I cut all my frames from the Russian Birch and never came across a single void. The wood has swelled slighly after the testing and other than a graying in colur, retains inital shape and hardness. When I bought the sheet, it was not bowed or warped, as you often find with cheaper plywood. It cut extremly clean with very little splintering. It was finished both sides without even the smallest of knots. The thin, 13 plies I guess add to the stability. I'm guessing this is cabinet grade plywood.

Although I live in a very "marine" location where commercial fishing is still big part of the economy and offshore oils is booming like you wouldn't believe, there is no marine plywood to be had locally. For me to order a 1/2" full sheet of Okoume, it would cost me 169.99 for the sheet and 98.00 to ship it + tax. Finding out that a 30.00, 2x4 sheet of Russian Birch will fit the bill, is just gravy!!

Cheers,

Sean