Film: Tricks & Advice
You’ll get the nicest result and finish on the final insulation if the insulation under the PVC end is straight and properly fitted. You can fix PVC Elbows and foil in several ways
Danmat is recommending gluing of PVC foil and Elbows in the overlap.
Bends and foil are held temporarily by a Wire. Then glue foil and Elbows under the overlap with PVC glue. Overlap it put on the back side of the pipe. Wire is to be dismantled afterwards. Finished work.
Rivets in the same color as vinyl and elbows pushed through both layers of film in the overlap. Deliberately placed on the back. Rivets may want. covered with tape.
All shock and longitudinal joints maintained with tape. Overlap it put on the back side of the pipe.