Wood veneer applications in surfboard construction : a study of impact resistance Bissell, Dave
Surfboards are manufactured with a shaped polyurethane foam core that is wrapped in fiberglass cloth, and sealed with multiple applications of a curing resin product. A graduating project was conducted to find a suitable method to replace the fiberglass with a wood based material, and perform tests to determine the comparable impact resistance qualities of the wood material with the standard fiberglass build method. The wood material selected was a woven veneer mat, made out of 10mm wide strips of Douglas fir veneer. Multiple versions of strip size and mat configurations were considered, with two final mats chosen: a densified, woven, 10mm strip mat, and a non-densified, woven, 10mm strip mat. Samples for testing consisted of a 6” x 6” x 1.25” 3lb/ft³ foam block, a fiber substrate (either a woven veneer mat or fiberglass) and a curing resin (either Polyester or Epoxy), with the fiber substrate bonded to the foam block with the resin. Samples were constructed according to standard surfboard building methods. Samples were tested using an Impact Testing Apparatus, which consisted of a vertically mounted piece of PVC pipe with holes drilled in the side at specific heights, and a plate underneath the pipe on which samples were placed for testing. A 320g steel ball was pushed through the holes in the pipe and dropped onto the face of each sample. Failure was determined to occur when circular cracks appeared in the surface of the sample that could be seen with the naked eye and felt with a bare finger, through which water could access the foam core in a typical surfboard. Samples made with Epoxy resin were approximately 150% stronger than those made with Polyester resin, when averaged across samples of all fiber substrates. Fiberglass samples were on average 115% stronger than woven veneer samples, ranging from a 50% difference between the strongest veneer sample and the weakest fiberglass sample, to 240% between the weakest veneer sample and the strongest fiberglass sample. The strongest sample used a 6oz – 4oz fiberglass combination with Epoxy resin, with the weakest sample using a Densified Woven Veneer mat and Polyester Resin. Densification of wood veneer prior to weaving made construction of the samples easier, as the material was more flexible and easier to weave, but resulted in weaker samples than those made with non-densified veneer. More veneer configurations should be designed and tested to further determine the viability of building a surfboard with wood veneer as opposed to fiberglass.
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