METHOD FOR MANUFACTURING A HOLLOW BODY, IN PARTICULAR A FUEL TANK

A method for manufacturing a hollow body, typically a tank, from a plastic material. The method comprises the steps of: - molding a preform into shells in a molding tool; - joining an insert to an inner surface of a shell of said shells, the insert defining a sub volume within the hollow body to be made; - joining together the shells to form the hollow body by closing the molding tool and applying a main pressure (P1') to a main volume enclosed by the shells. It is proposed to apply a sub pressure (P2') to the sub volume whilst applying the main pressure (P1') to the main volume, such that a pressure difference between the main volume and the sub volume is bigger than 0,20 bar (P1' - P2' > 0,20 bar) and smaller than 3,00 bar (P1' - P2' < 3,00 bar).