a fiber - reinforced plastic structure is obtained by weaving fibers in one direction about one or more spacing members located angularly to the fibers . the fibers may be either warp or woof stands , the spacing member serving as woof when the fibers from warp strands , and as warp when the fibers form woof strands . the removal of the spacing member leaves relatively large open channels forming , in effect , a multi - wall hollow structure . the resultant structure may be partially or completely treated with a plastic resin system prior to or after the removal of some or all of the members . the solidified resin reinforced structure may be filled with a foam - in - place plastic , and it may be stacked in layers to provide additional thickness with reinforcing fibers running in different directions for additional strength . some fibers may extend from one ply into an adjacent ply or into more remote plies . the hardened structure may also be stacked to provide a honeycomb configuration and may be sliced into thin sections with sheets of additional fiber - reinforced plastic material on each side or each end to produce a structure of high strength - to - weight characteristics .