Making a surfboard is like making a sculpture, says Harris. Both sculptors and board makers use different materials to build a 3-D shape. But unlike most sculptures, a surfboard needs to float. That means it has to be less dense, or contain less matter in a given space, than the water around it.
All new surfboards begin as a rectangular block of lightweight foam, called a blank. In the center of the blank is a long piece of wood that strengthens it. Board makers shape the foam using machines or by hand. A surfboard’s unique shape helps it ride a wave.
On top of the foam, board makers add a layer of strong woven material, often made of fiberglass. They coat the board with a liquid called resin that hardens as it dries. Most resin is made of plastic, but Harris uses resin that comes from plants!
The board is then sanded smooth. Finally, one or more fins are added to its underside to help it steer through water.