Abstract: A liquid-tight paperboard container having at least one radiused corner is disclosed, together with a method for manufacturing it. The container includes a sidewall member having a bottom edge portion folded under a bottom piece to define a flange which is sealed to the bottom piece by means of heat and pressure. The region of the seal between the flange and the bottom piece is defined by a knurled surface on the flange. This permits the formation of a high quality, reliably liquid-tight container using relatively low pressures. In addition, the portions of the bottom edge of the sidewall member adjacent the radiused corners of the container are preferably provided with slits or notches to limit the buckling that occurs during the process of folding the edge under the bottom piece. By doing this, in combination with the use of a knurled for sealing, containers having corners with unusually small radii of curvature be reliably, easily and inexpensively manufactured.