Marine Plywood VS AC Fir Plywood
There are two plywood adhesives: Interior, which doesn't stand up to frequent wetting, and Exterior, which isn't affected by long-term wetting and would typically be called waterproof. Marine grade uses exterior adhesive. This is the same adhesive as used in AC Exterior grade plywood.
With marine grade, the lowest grade veneer that can be used is "B," which means that there will be no voids on the surface or in the interior plies. Marine grade can be sawn without getting an interior void on a freshly cut edge. The edges will be totally solid. AC plywood will have no voids on the “A” side and can potentially have interior voids.
There are a number of species of wood used for marine grade plywood. Douglas Fir is certainly the most popular but other species are often used in marine grade plywood. You can get the same performance from exterior AC plywood in nearly all cases.
Marine grade has no natural decay resistance. It has no chemicals added to enhance decay resistance, unless it has been subsequently pressure treated. Marine grade has no special waterproofing in or on the wood.
Most boat builders that still use plywood in the construction of the transom in a fiberglass boat use AC plywood. Nearly all plywood that is incorporated into the fiberglass construction of a boat is very likely AC plywood.
There are certainly many applications in boat construction that we would recommend Marine Grade plywood but when it is going to be encapsulated in fiberglass AC is a much cheaper alternative that works just as well.
With marine grade, the lowest grade veneer that can be used is "B," which means that there will be no voids on the surface or in the interior plies. Marine grade can be sawn without getting an interior void on a freshly cut edge. The edges will be totally solid. AC plywood will have no voids on the “A” side and can potentially have interior voids.
There are a number of species of wood used for marine grade plywood. Douglas Fir is certainly the most popular but other species are often used in marine grade plywood. You can get the same performance from exterior AC plywood in nearly all cases.
Marine grade has no natural decay resistance. It has no chemicals added to enhance decay resistance, unless it has been subsequently pressure treated. Marine grade has no special waterproofing in or on the wood.
Most boat builders that still use plywood in the construction of the transom in a fiberglass boat use AC plywood. Nearly all plywood that is incorporated into the fiberglass construction of a boat is very likely AC plywood.
There are certainly many applications in boat construction that we would recommend Marine Grade plywood but when it is going to be encapsulated in fiberglass AC is a much cheaper alternative that works just as well.