It is important that the sealing of the polyester is as permanent as the polyester itself, which is why each product is hand-made on the patented Polyweld machine. Polyweld is a method of sealing the edge of the polyester sheets without using any adhesives, solvents or additives of any kind. Through heat, this method 're-extrudes' the polyester to provide a seal that is as strong as the original material, with a unique smooth, rolled edge.