(Following compliments of Drew Eckhardt, drew@Colorado.EDU)

On wrapping material: You have the choice of fiberglass cloth in various weights, cloth pre-impregnated with resin before you laminate, and mixtures of fiberglass and carbon fiber or kevlar which will get you the stiffness of more fiberglass without the weight.

On edges: Carbon steel. Go for a solid edge all the way around instead of the cracked, segmented edges companies sometimes use - it's too easy to blow out the segmented edges although they purportedly provide for a more even flex.

On the core: Most boards use either a vertically laminated wood core, or foam core. You'll want to use the vertical wood, since it won't break down over time and has a better feeling flex. To hold the bindings on, some companies laminate steel inserts between the wood strips, others go for an aluminum or titanium plate laminated in the binding area. The former affects overall flex less.

Of course, all of this is a gross oversimplification. Flex, camber, and sidecut shape all interact with how a board handles, and no one gets it right the first time - expect to make several molds, and ride them, and go back to the drawing board.

There are also little things which have a significant effect on how the board rides - i.e., vibration damping materials like rubber in the nose and tail, and sometimes between the sidewall and edge.

Sidewall geometry will affect edge hold, flex, and durability.