Abstract: The reusable welded hermetic enclosure and method provides a laser weld between a cover and a chassis to form an enclosure or a laser weld between two parts to form a hermetic seal. In either event, one part has an open mouth with a sloped or tapered external section surrounding the mouth to receive the larger mouth of the other part. The mouth of the other part is sloped or tapered to conform to the sloped or tapered external section of the first part. The parts are pressed together for an interference fit to eliminate gaps and the laser weld connects the sloped or tapered sections. When the materials to be welded are of low silicon content aluminum, it is necessary to include a filler ring of an aluminum-silicon alloy containing a predetermined silicon content between the sloped or tapered sections. The cover and the chassis are reusable after opening. The filler ring is sacrificed during the removal of the cover.