Method of shaping container bodies and corresponding apparatus

Method for reshaping a skirt (12) of a metal hollow container (1, 6) having an upper open end typically formed (10) with an opening (11) and / or less typically shaped end (14), in which a) said container (1, 6) is located in a mold of two mold halves (2) having an internal shaped wall (21), b) an internal pressure P of a fluid, typically air is set during a time interval DeltaT inside said container space, forming a cavity (15) such that said skirt (12) by expanding it against said shaped wall (21) is satisfied, defining said shaped wall (21) with an inner surface (210) lateral space (211) typically kept at atmospheric pressure, characterized in that an external pressure P 'of a fluid, typically air, in said contiguous to an external or upper surface (100) of said upper space (101) applies open upper end (10) and / or in said lower space (141) contiguous to an external or lower surface (140) of said shaped bottom end (14), so as to achieve, during said time interval DeltaT a deltaP pressure difference = | P-P '| low enough to prevent any distortion of said open top end forming (10) and / or said shaped bottom end (14), so that a shaped metallic container (1 ', 6' ') is formed, said difference pressure below 0.05 MPa deltaP for a thickness of 0,2 mm when the container is made of aluminum, or for a thickness of 0.17 mm when the container is made of steel.