In general, cured laminated fiberglass cloth is stiff and will not flex much without cracking and breaking. This is typical when using a 5:1 epoxy resin and polyester resins. The tensile elongation for traditional 5:1 epoxy resin is 4.5% with slow hardener and 3.5% with fast hardener. Our Totalboat High Performance Epoxy Resin (2:1 mix ratio) is more flexible than 5:1 epoxy resin and polyester resin.