In this production method, two smooth products are obtained by using two molds, male and female. RTM fiber etc. between two separate molds designed for RTM. reinforcements are placed and the molds are closed. From a pre-prepared injection point, a pressure controlled RTM Machine injects the resin into the closed molds. Compared to hand lay-up, productivity and product quality are higher with RTM. With this method, large and complex parts as well as sandwich products can be molded in a single process and different wall thicknesses can be achieved in different areas. As a result of the exothermic reaction, the heat generated due to the hardening of the resin will also heat the mold, providing an advantage in molding time. Since the resin is cured in a closed environment, the RTM method releases less chemical vapors into the environment.