The first stage (Fig. 5a–d) consists in the fabrication of a prepreg layer. Two reinforcement layers (either UD flax alone or UD flax-paper depending of the plaque type to be molded) are removed from the drying oven and placed on a Teflon sheet covering a steel plate (which is used for rigidity and heat transfer during molding), with the flax fibers aligned in the same direction for the two layers.