That is not "epoxy" it is cheap polyester resin. It will crack at every joint after one season without the required fiberglass. A few layers of CSM faired with micro balloons, inside and out will make it look factory, then paint it with poly urethane (not poly acrylic) 2 part of decent quality. as one post said, generous radiuses help immensily. I generally use plywood but for a project this small some scrap peices of NidaCore or Devinacell from a local boat yard would be better.