A generally rectangular rigid pressure pad for use in the formation of the bottom of a carton formed of infolded panels of a paperboard having heat sealable surfaces, the pad having first and second opposite surfaces (142 and 122), first, second and third side edges (121, 123, and 125), and including a longitudinal centerline extending through the thickness of the pad normal to the opposite flat surfaces of the pad, first and second transverse centerlines (129 and 135) extending between respective opposite sides of the pad, a cross-sectional plane parallel to the opposite flat surfaces of the pad, the first surface of the pad being adapted to engage and apply a sealing pressure against the infolded bottom panels upon capture of the infolded bottom panels between the pressure pad and a mandrel, characterized in that: the pressure pad has surfaces, which engage the infolded panels, that define four quadrantal regions (150, 152, 154, 156), the pressure pad having four generally triangular-shaped quadrantal pressure portions configured to apply sealing pressure against the infolded bottom panels, each of the quadrantal pressure portions substantially corresponding to a respective one of said quadrantal regions (150, 152, 154, 156), each of the quadrantal pressure portions having one of their apices (158, 160, 162, 164) disposed at the center of the pad and each of their other apices disposed at a corner (172, 174, 180, 182) of the pad, an opposite two of said quadrantal pressure portions being of a size less than the other opposite two of said quadrantal pressure portions, at least one of said quadrantal pressure portions including a first sculpted projection having a flat outboard surface disposed substantially parallel to the cross-sectional plane of the pad and extending to a first height from that surface of the pad facing the mandrel and defining a platform for establishing a separation distance between the pressure pad and the mandrel, each of said quadrantal pressure portions having a sculpted surface including at least a second projection extending from said sculpted surface of the pressure pad and defining a flat outboard surface which faces the mandrel and which is oriented in a plane that is essentially parallel to the cross-sectional plane of the pressure pad, and which extends to a height which is less than said first height and being a function of the wall thickness of the paperboard. the pressure pad has surfaces, which engage the infolded panels, that define four quadrantal regions (150, 152, 154, 156), the pressure pad having four generally triangular-shaped quadrantal pressure portions configured to apply sealing pressure against the infolded bottom panels, each of the quadrantal pressure portions substantially corresponding to a respective one of said quadrantal regions (150, 152, 154, 156), each of the quadrantal pressure portions having one of their apices (158, 160, 162, 164) disposed at the center of the pad and each of their other apices disposed at a corner (172, 174, 180, 182) of the pad, an opposite two of said quadrantal pressure portions being of a size less than the other opposite two of said quadrantal pressure portions, at least one of said quadrantal pressure portions including a first sculpted projection having a flat outboard surface disposed substantially parallel to the cross-sectional plane of the pad and extending to a first height from that surface of the pad facing the mandrel and defining a platform for establishing a separation distance between the pressure pad and the mandrel, each of said quadrantal pressure portions having a sculpted surface including at least a second projection extending from said sculpted surface of the pressure pad and defining a flat outboard surface which faces the mandrel and which is oriented in a plane that is essentially parallel to the cross-sectional plane of the pressure pad, and which extends to a height which is less than said first height and being a function of the wall thickness of the paperboard.