The present invention provides a configuration of a computer-chassis containment or other electromagnetic device method for manufacture in which a “one-hit” solution may be implemented to provide adequate electromagnetic interference shielding (EMC shielding) and is configured such that shielding gaskets, “spoons” or other excessive structures may be reduced or eliminated completely. Patterned sinusoidal “patterns” that are stamped, molded, cut, or extruded into one or more sides of a “box” provide sufficient EMI shielding, such that the need for gaskets is reduced or eliminated.