Details matter. The key to details like this roof rail, is being methodical, and taking it one step at a time. You have to start by establishing a surface to work off of first. In this case, it is the roof, and taping the top edge of the roof rail to the correct shape. Here are the remaining steps.
•Fill up to the two sided tape that was on the roof.
•Get that filler roughly sanded in.
•Fill the bottom half of the reverse curve with enough filler to sand the face of it, and the reverse curve part. You want to be able to square up that outside corner and get it straight.
•Block sand the face of it to the correct contour.
•Tape that front edge so it’s an even thickness for the length of the roof.
•Sand the revers part down to that tape line.
•Once your lines and corners are established, finish up some of the details, making sure the corners stay straight and sharp.
•Sand a radius back into all the corners.
