To make it look good is to make it look factory and to make it look factory the fender needs to be trimmed evenly all the way around - not just the front and back.
The opening measures 90cm (cars are metric and so are my measurements) inside diameter and the outside diameter of the flat face of the fender is 99cm. I cut 4 cm off to leave a 5mm lip and total inside diameter of 98cm. For comparison, a stock Ford F150 has a fender inside diameter of 99cm.
The key to this project was this little tracing tool. It took a few iterations to come up with a shape that sits flat and square on the fender and can trace the line precisely without relying on a steady hand. It took over an hour to make the tool but then only seconds to draw the lines, and they were perfect.
The fender is covered in clear masking film because it is much tougher than masking tape.
Ready to cut. Did I mention there are no dings or rust in this body?
This is a 36 tpi blade for thin metal. I cut through the plastic and metal in one pass.
The blade isn't long enough to cut all the way through this flange and it will buck if you try. I used a hacksaw blade to finish it.
The highlight shows the 5mm of flat surface not being cut away. I felt cutting it away entirely would give it an unfinished look.
Taping the dangling end in place while cutting keeps it from flopping around and bending before the cut is complete.
By going slowly and stopping frequently I kept tight to the line and it needed minimal sanding.
To me, this is how the car should look from the factory. The sheet metal is super flimsy now so I will back it up with epoxy fiberglass this weekend and build up an inside flange, then I will modify the wheel well liners and put them back in.
The back is going to be much harder and require welding. I'll do that over the holidays.
