I have read a lot of posts and tips and tricks around getting straight crisp body lines when they are protruding corners (top of a fender for instance). Use the tape method below the line, fill above, block sand to the line then put the tape on top of the line and repeat the process. Then gently round the corner to the appropriate radius. I have used this method and it works.
But I have a crease body line that is indented (internal, pushed in) I am working on. It is a shallow angle crease, I think it would be easier if there was more of an angle between the panels. (It happens to be along the bottom of the rear window on the cab of a 2001 F150′ for those familiar). Anyhow, I taped the center of the crease from the bottom and blocked the top, then reversed the procedure blocked the bottom. But that results in a sharp Vee that does not have the appropriate radius at the bottom. So now I need to fill the Vee to get the radius. I am thinking I can tape along both the top and bottom of the filled area leaving a gap between the tapes. then block with a round block to get the radius right without sanding the top and bottom panels which have already been blocked.
This might work, but I am wondering how others do these type of body lines.
By way of background, I have painted half a dozen cars in my life, I’m a good welder and metal fabricator, decent mechanic, and engineer by trade. My body work is getting better over the years since my first VW bug when I was 16 yrs old.
Looking forward to hearing how you pros and those classic car guys get it right.