Speaking of mysteries, I just figured out a way to roll PE parts. I had a part in the engine exhaust that needed to be rolled so I could glue four mounting brackets thst keeps things aligned. What I did was find a drill bit that was the same diameter I needed and one just a hair larger. Using the plastic (lack of better words) bending wedge that comes with the Bending tool I purchased, I laid out the piece needing rolled, laid the plastic tool underneath the PE part and slowly started rolling the larger drill bit perpendicular to the PE part while maintaining a slight up angle (Less than 20 degrees), with the bender. You have to pull the bender as you roll the drill bit over the PE part. I did this a couple of time each time increasing the angle on the bending wedge. Then I turned the PE part around and start the same process so each end ended up curved. Then I went to a smaller drill bit to tighten the circle up. Surprising it worked and someone else probably discovered this long before me. I'll edit this later a post an image or two showing what it looks like and the parts I used. I couldn't take a picture why I was doing it because I did not have enough hands Darn-it.
Here are the images I promised, not very good but should give you an idea.
The first one shows how I used the drill bit and the bending wedge. Remember I pulled the wedge while I was rolling the drill bit over the PE piece. You can see the can cap to the left.
The Second image shows what the piece looked like after I rolled it a few times.
Finally the finished product (only took 3.5 hours to build)
Charlie