A method and system for closing and sealing an end of bag (100) taken from multiple bags each made of polymeric material and sealed at one end, conveying the bag along a hot air manifold (700) to heat adhesive material on a first section (202) of the bag to an adhesive state and to heat adhesive material on a stepped construction of the bag to an adhesive state, after the bag has been filled with contents and closed, and the bag creased to provide a fold line, a blade (606) to bias the stepped construction of the bag to follow along the manifold while the bag is being conveyed, a trailing end (606) of the blade to fold the bag and to be followed by applying clamping pressure to form an adhesive-to-adhesive seal, which seals the end of the bag through which end the bag has been filled with contents.