Subject

Building a male mold for a bimini is very straight forward.

A basic 4x8 sheet of 3ply, 1/2" plywood is about 42 lbs.

Divinycell foam is about 6 lbs/ft3.

Trying to fabricate a bimini using plywood will end up being a top
heavy slug and totally change the sailing characterstics.

You simply don't want to go there.

Lew