Maybe 18 years ago, I "fixed" my turbo inlet pipe. It was cracked at both ends along the seam and on this one end the crack traveled off to the side. I had heard that it isn't possible to glue polypropylene or polyethylene, so I scuffed the surface to get some sort of mechanical bond. I also applied fiberglass (?) window screen to reinforce those cracked areas. I used some sort of epoxy - I forget what brand. Years later, I found an '85 Turbo in the junkyard with only 50K on it and bought that pipe to use. I was surprised that the glued pipe held together all that time.