a method of forming fiber reinforced polymer matrix composite structures having a low volume fraction of fiber reinforcement and carefully controlled thicknesses is provided . the method enables the production of composite structures having a fiber volume fraction of less than about 0 . 5 through the use of vacuum bag molding , thereby eliminating the need for expensive closed molds , the method also eliminates the occurrence of “ racetracking ” of uncured resin during the resin infusion process .