Abstract: A molding tool comprises a mold component having a body, a molding surface thereon, and at least one passage internal to the body for conducting a heat transfer fluid from an inlet thereto to an outlet therefrom, the passage comprising a roof spaced from and located proximate the molding surface, a floor spaced from the roof and located farther from the molding surface than the roof, the roof and floor being joined to define a passage cross section, wherein the roof extends within the tooling body so as to substantially conform in size and shape to one or more contours of the molding surface and at least one of the area of the passage cross section and the offset distance of the passage from the molding surface varies between the inlet and outlet. Advantageously, the passage comprises at least one support pillar to constrain deflection of the molding surface during molding.