I am working on this as we speak what i am doing is fixing a car that some one else painted and the sealer has cracked and looks terrible .I want to fix with out painting the whole roof over .
step one tape roof off in the jamb twice.
step two using a small file scrape out old stuff to the metal carfully.
step three sand with 180 on homemade paint stick the thick 5 gal bucket type cut down.
step four treat with por-15 metal ready
step five paint with por -15 paint small brush works well .
step six retape and seam seal with hytec sealer from eastwood.
step seven smooth with solvent dipped paint stick
step eight retape & paint.(use no primer on seam sealer that is why it cracks prematurely)
step nine clear coat
step ten buff roof close to jamb to blend in .
this is what i am doing to fix a mistake .hope this helps with your project.....CJ
ps step eleven