If the factory primers adhesion is that great - Why not just Utilize it .....???


Your not going to get a better adhesion & if your already most of the way there - I would consider finishing it up with some 220 & spraying on a Poly primer & block it out...........

Some primers adhere better to other surfacers than others so be sure to double check if a Epoxy, Poly, 1k laquer , or 2k Urethane would best suit your needs ........

If its to bare metal - You would have to etch it first or use an Epoxy & then primer again .........


I guess its up to you how confident you are about the Exhisting primer