A manufacturing method contemplates performing vacuum-assisted resin infusion to enclose an elongated core within a cured composite laminate without employing a mold. Not relying upon an external mold enables the process to be efficiently performed for core shapes that are manufactured in low volumes. Typical resin infusion processes utilize flow media that induces bag bridging during vacuum draw in order to provide gaps facilitating resin flow. However, popular flow media also tends to impart directional aggregate forces during vacuum draw, which forces can deform the core since no mold is being used. To avoid unequal and non-dispersed directional forces from deforming the elongated core, a flow media is employed that is configured to disperse and/or reduce such forces. Some such flow media may be knitted so as to allow overlapping strands to slide over one another. Other flow media may ensure that strands are interleaved so that no one strand or group of strands is disposed outwardly of other strands along a substantial length of the strands, thus dispersing bag bridging forces in several directions and avoiding directional aggregate forces. However, such flow media may have inhibited resin flow relative to popular high-flow flow media, and thus new strategies have been developed to ensure appropriate wetting of fibrous reinforcement. An adjustable brace can also be employed to restrain the elongated core from deflecting during application of vacuum and/or resin infusion.