: No. Normally I wouldn't use any of them for frames on a SOF baots.
: The MDO is basically covered with paper. Great for printing
: signs, but it doesn't appeal to me for somthing that will be
: wet. MDF would be a bit more durable, but again, the fiberboard
: will swell when wet, and won't shrink back to the old size when
: it dries. If this is all you have then go with it, but seal it
: well with epoxy, and don't grouse about the weight.

: OSB is strong and would probably work, but it seems pretty flexible
: for its size. I'd use a piece of 1x1 solid wood t stiffen it on
: the larger frames if i needed to. It looks ugly, but that can be
: covered with paint. One side is rough. Tat side goes toward the
: ends, and that is the side you glue nd screw the stiffeners to ,
: so from the cockpit all you see are the smooth, nicely painted
: sides of the frames.

: Plywood is simpler and faster to cut and finish. The other options
: will take more time. If you are trying to save money on building
: a lot of boats, say for a Boy Scout troop, build one with the
: meterial as a test before you commit to all of the projects.

: Just my thoughts here.

: PGJ

MDO is fairly high quality plywood with a fiber lamiminated to each side. Think about it, most signs made from the stuff are outside for years, works fine on kayaks. Btw, the fiber surfaces finish really nicely, though you get a tan colored wood, almost looks painted. Oils well too.

MDF is much like a finer chip version of particle board, it's not to be used outside.

OSB isn't waterproof, much like MDF, bad idea on kayaks.

Bill H.