Isostatic molding process and seal

In a process for the isostatic forming of plastic liners within hollow bodies having generally flat-faced flanges disposed about openings thereof, the method comprising providing a flanged hollow body to be lined, the body having at least one generally flat-faced flange, the flange having a generally radially extending planar surface and a centrally disposed opening therein, disposing within the body a powder to be compacted to form a lining, disposing a flexible membrane within the body and the powder to be compacted, the flexible membrane maintaining the powder in a desired position, supporting and sealing the membrane adjacent the flanged opening of the article with a flanged end cap, hydraulically sealing the flexible member to said end cap and subsequently immersing the body in a hydraulic liquid and applying pressure thereto sufficient to compact the powder to a desired degree, subsequently removing the end cap and flexible member to provide a compacted-powder lined body, the improvement which comprises providing an end cap having an annular recess formed in a mating surface thereof, the recess having a radial cross-sectional configuration which is generally rectangular, disposing a generally resilient liquid impervious annular sealing member within said groove, the annular sealing member having a radial, generally rectangular configuration such that when the sealing member is disposed within the groove, the sealing member projects therefrom and when the flanges of the end cap and article to be lined are forced into contact, the sealing ring is deformed to fill the groove and any adjacent irregularities in the flange of the body to be lined.