Abstract: A method is provided for accurately determining the volume of gas that has leaked through and around a cap having a mouth and a seal situated about the circumference of the mouth. The method includes the steps of positioning the cap within a testing neck on a fuel cap testing apparatus, fixing the cap in the neck to create a general sealing engagement between the seal and the neck and to cause the seal to move into the neck, and "staging" the cap for at least 2.5 seconds. Staging refers to the necessary waiting period that must pass in order to allow the seal to complete moving into the testing neck. A test is then conducted for changes in pressure within the testing neck due to low-volume gas leaks through and around the cap.

Abstract: A method is provided for producing an end plate for a container having a continuous wall, with a novel end plate being produced thereby. The end plate includes a thickened plate which is disposed perpendicular to the continuous wall, with the thickened plate having a diameter less than the inner diameter of the cylindrical walls. A sheet having a peripheral down-turned flange is disposed above the thickened plate, with the down-turned flange having a diameter greater than the diameter of the cylindrical walls. An opening is provided in the sheet which is aligned with an opening in the thickened plate. An end portion of the continuous wall is bent outwardly to form a peripheral lip which has an outer diameter less than the diameter of the sheet. A seam between the continuous wall and the metal sheet is formed by inserting a stud into the opening and engaging a groove-containing roller to the down-turned flange and peripheral lip.