If someone says welding, you probably think of torch welders joining metal and imagine someone working on a large building or vehicle frame. Welding PVC fabric with radio waves is actually how the very best inflatable outdoor movie screens are built.
Essentially, a focused beam of amplified high-frequency radio waves fuses overlapping layers of movie screen fabric from inside to outside.
RF welded bonds are super strong, reliable and long lasting. The work takes longer and much more skill than sewing.