Welding v's. Gluing
Why is welding better for inflatable manufacture than gluing?
Welding is a better process because it will last indefinitely. Glued parts are subject to the glue getting “tired” and letting go. The process of welding, fuses two like coated materials together, and there is no adhesive interface. A welded lap seam is stronger in a shear direction than the base fabric. A glued lap seam is stronger in that direction too until the glue gets “tired” and will let go.
What makes the glue let go?
Plasticizer migration is what is responsible for adhesive bonds losing their strength over time. The plasticizer is the same thing in the coating that keeps the UV radiation from destroying your boat. This is one reason why PVC boats last so long under UV, but also the reason why the glue can let go after a number of years. This migration process is accelerated with heat and Humidity.
How long will the seams last?
In general, the further North your boat is used within Australia, then the quicker the glued seams will let go. In the far North you may only get 2 years before the glue fails, otherwise 7 years is the approximate life span. Whereas a welded seam should last indefinitely.