Abstract: To form a seam of attractive appearance, a heated platen having a shaped lip acts to engage and press the central surface of an adhesively-backed sheet of a polymeric fabric against the top appearance surface of a panel and the peripheral edge of the sheet into a groove formed in the surface, the platen activating the adhesive and the lip forcing a potion of the adhesive inwardly adjacent to the sheet edge against one wall of the groove. An insertion blade presses a portion of the sheet edge towards the bottom of the groove, the blade acting as a heat shield to space and protect the other wall of the groove from the heated platen.