Plastics Welding

Hot air welding, is a plastic welding technique using heat. A
specially designed heat gun, called a hot air welder, produces a jet of
hot air that softens both the parts to be joined and a plastic filler
rod, all of which must be of the same or a very similar plastic. This is
done to molecularly weld similar plastics together to create virtually
anything that can be fabricated from tanks to brackets to trays.