NOVELTY - The reinforcement (1) for molding a fiber based layer, comprises a thick and aerated internal layer (2) made of fibers, external layers (3, 4) disposed to one another in the internal layer, and an intermediate layer between the internal and external layers. The external layers comprise fiber sections (3a, 4a) with a thermofusible surface. Some of the sections penetrate according to their length in the internal layer and partially adheres between the glass fibers of the internal layer. The internal layer comprises continuous glass fibers (2a) randomly oriented as a mesh.    USE - The reinforcement for molding a fiber based layer is useful for manufacturing wind turbine blades and other composite parts.    ADVANTAGE - The reinforcement exhibits high flexibility and high strain capacity, effectively molds a fiber based layer without risk of fraying or degradation of the edges of the fiber based layer, and provides good penetration of the resin during molding thus desirably increasing the mechanical properties such as tensile strength and bending resistance of the composite parts.    DETAILED DESCRIPTION - The reinforcement (1) for molding a fiber based layer, comprises a thick and aerated internal layer (2) made of fibers, external layers (3, 4) disposed to one another in the internal layer, and an intermediate layer between the internal and external layers. The external layers comprise fiber sections (3a, 4a) with a thermofusible surface. Some of the sections penetrate according to their length in the internal layer and partially adheres between the glass fibers of the internal layer. The internal layer comprises continuous glass fibers (2a) randomly oriented as a mesh. The meshes of glass fiber have a content of 2400-4800 tex. The glass fibers are formed of an assembly of filaments having a diameter of 14-17 mu m, and have a content of 40-80 tex. The reinforcement has a weight of 400-1800 g/m2, and is present in the form of a web-conditioned continuous band. An INDEPENDENT CLAIM is included for a process for fabricating a molding reinforcement.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic cross-sectional view of a molding reinforcement.    Molding reinforcement (1)    Internal layer (2)    Continuous glass fibers (2a)    External layers (3, 4)    Sections with thermofusible surface. (3a, 4a)