I have a curved pipe. This pipe will ultimately be fabricated as a thin-wall stainless steel pipe. The pipe will be approximately 4" in diameter and 6' long. I would like to know how to cut a slot 1" wide the full length of the pipe and keep the same exact curve. Also, the curved pipe does not curve uniformly, it has a decreasing radius as you move to the two ends of the pipe.
Here is a top and side view of the pipe: