I have an idea for a new swim platform. It will require using 2x6's. i was thinking of making the 2x6's out of fiberglass wrapped around 2 inch pink foam. how many layers of 1708 will be required for supporting weight between a 18 inch span
well i dont know how many layers it would take for strenght around foam.
I would wrap a 2x4 a couple time and then clamp the ends to sawhorses or set weights on the ends of each board. the fiberglass will dry, and the would should be pretty stout at that point.