Dunnage air bag

A dunnage air bag is formed from two rectangular sheets. Each sheet is formed by a polyethylene layer adhesively bonded to a liner board layer. An air valve is mounted through one of the sheets to enable the dunnage air bag to be selectively filled with air. The sheets are disposed in overlying offset relation, with the polyethylene faces of the sheets in contact. A rectangular bladder is created by heat welding the polyethylene layers together, through the liner board layer, in a rectangular heat weld. Offset flaps of the sheets are then folded over on fold lines disposed interiorly of the heat weld and adhesively secured in order to reinforce the bladder and minimize stress on the heat weld. In alternative constructions, the polyethylene layer may be dimensionally smaller than the liner board layer such that a strip of liner board remains exposed along one or more peripheral edges of the polyethylene face of the laminate sheet. Consequently, subsequent folding and adhesive securement of the offset flaps during manufacture of the dunnage air bag results in liner board to liner board adhesive bonds rather than liner board to polyethylene adhesive bonds.