Marine plywood description

[halmc]

I can get "marine plywood" from a local building supply house considerably cheaper than from on line folks cuz I don't have to pay for shipping, and because I have an existing business relationship with them.

But before I do so, I want to ensure that I'm getting the same quality.

Is there an industry standard description of "marine plywood"?

And yes, I know, some on line folks offer "free shipping" but with the local folks, I get to look at it before I pay for it.

TIA!

[MH Hawker]

To start off it will have 7 layers instead of the normal 5 and is considerably more rigid. It will also have no voids in it any knot holes will be replaced with a plug normally a football shaped looking thing. Both sides will have a finished look. Mine ran 65.00 a sheet.

[wijames]

To start off it will have 7 layers instead of the normal 5 and is considerably more rigid. It will also have no voids in it any knot holes will be replaced with a plug normally a football shaped looking thing. Both sides will have a finished look. Mine ran 65.00 a sheet.

Is marine plywood coated or treated in some way or just better construction?

[HandymanHerb]

Both

Marine plywood is an expensive, water-resistant grade that is more tightly constructed and glued than ordinary plywood

[sunedog]

"Marine-grade plywood is a specially designed panel made entirely of Douglas-fir or Western Larch. The grade of all plies of veneer is B or better, which means it may have knots, but no knotholes. The panels are sanded on both faces, and are also available with Medium Density Overlay (MDO) or High Density Overlay (HDO) faces. The maximum core-gap size permitted is 1/8 inch. Its exposure durability rating is EXTERIOR and the glue used is a fully waterproof structural adhesive. It is considered a “premium” panel grade for use in situations where these characteristics are required, i.e., for boat hulls and other marine applications where bending is involved.

Marine-grade plywood is available in 4x8-foot sheets of 1/4, 3/8, 1/2, 5/8 and 3/4-inch thickness. Sheets up to 5x12 feet are also available. Available grades are A-A, A-B, B-B (face-back), MDO and HDO.

Marine-grade plywood is not treated with any chemicals to enhance its resistance to decay. If decay is a concern, it should be pressure-preservative treated to an appropriate standard."

http://www.apawood.org/level_b.cfm?cont ... prd_marine

I bolded the type above to highlight it is not treated lumber like you find at Lowes. Treated plywood won't rot, but it is usually curvey as hell because of the wet treating process so it's hard to work with. And it will delaminate.

* edited to add linky

[Bamaman]

You might find marine plywood for $65 or $75 per 4x8 sheet (3/4"). But you're not going to see the stuff at any $35 per sheet.

It's the only stuff to use in any boat. And it's actually a good value because it's going to last more twice as long.

If you look closely, there are plywood distributors in just about every mid size and large cities. They sell quite a bit of plywood for furniture and cabinet makers, and sometimes will be in the engineered truss business.

I'm in a city of 55,000, and we have a plywood dealership 2 miles from me.

[OK Toon]

I wish I could have found some of the $65-$75 price range marine plywood. I had to have 8 sheets to resurface part of my boat dock and the best price I could find locally was $96 per 4'x8'x3/4".