Apparatus for making a polyolefin tank within a metallic tank

A fixture closing the flanged fitting of a metallic tank when forming a rigid polyolefin tank within the metallic tank by a rotational molding technique, said flange having an outer peripheral edge, comprising a pair of semi-circular collars having a side wall and a bottom wall, said bottom wall having an inner face and an outer face, the bottom wall of each collar having an inner peripheral edge engaging the outer peripheral edge of the metallic tank fitting flange to provide a continuous surface for the flow of polyolefin during the molding process, a semi-circular ring member secured to the outer face of the bottom wall adjacent to the inner peripheral edge portion thereof, a portion of one face of said semi-circular ring member sealingly engaging the underside surface of the metallic tank flange and extending across the peripheral edges of said collars and flange, and a bolt assembly clamping the semi-circular collars together on the flange of said fitting to form a continuous collar around said fittings.