Dunnage bag

In an expandable dunnage bag having an airtight bladder, a multi-ply tube formed of a plurality of bladder reinforcing sheets enclosing the bladder, and a valve extending through the sheets through which air is introduced into the bladder to expand the bag, the improvement comprising

• a moisture resistant coating on the outermost one of the sheets;
• a moisture resistant overslip surrounding each of two opposite ends of the bag, the overslips together surrounding only a minor portion of the bag, each overslip being made of thermoplastic material compatible with the coating on the outermost sheet and having an open and closed end, the closed end of each overslip being adjacent the outermost edge of the end of the bag the overslip surrounds and the open end of each overslip being heat sealed to the outermost sheet;
• the outermost sheet having at least one seam extending from one to the other of the two opposite ends of the bag, the overslips each covering an end of the seam and a moisture resistant tape covering the portion of the seam between the seam ends;
• portions of one of the overslips defining an opening through which the valve extends, the opening having a diameter substantially equal to the inside diameter of the valve, so that the opening defining portions tightly fit around the valve;
• a first clip through which the valve extends, the first clip underlying the opening defining portions of the first overslip and being in frictional engagement with the valve;
• a bag handle through which the valve extends, the handle overlying the opening defining portions of the first overslip and having a cap for sealing the valve;
• a second clip overlying the opening defining portions of the first overslip and being in frictional engagement with the valve, so that the opening defining portions of the first overslip are positioned between the first and second clips, whereby the overslips and coating weatherproof the bag by preventing moisture from pervading the sheets.