Abstract: The assembly (10) includes a plurality tubes (30) configured to fit into the trenches of a preformed seat cushion assembly (14). The plurality of tubes (30) rotate about pins (56) and force a fabric bag (12) and an adhesive layer located between the seat cushion assembly (14) and the fabric bag (12) into the trenches. Steam passes through the plurality of tubes (30) and out a plurality of holes (32) which are spaced along the plurality of tubes (30). The steam melts the adhesive layer which subsequently bonds the fabric bag (12) to the seat cushion assembly (14) within the trenches of the seat cushion assembly (14). A vacuum (40) is used to create a pressure differential between the passageways within the plurality of tubes (30) and the atmosphere, i.e., the seat cushion (15). The pressure differential is used to remove the steam and any water from the fabric bag (12) and seat cushion assembly (14) to prevent water damage thereto.