fender undercoating question

[gideup]

On my 65 FB I have removed the outer fender and I am in the process of scraping off the old inner coating that is on the back side of the fender and chassis. My question is how to restore the metal and coating. The metal for the most part is in really good condition. Should I prime and paint then put underbody coating on or should I just put the underbody coating on. There are some areas of surface rust. Should I coat over the rust or remove it to bare metal, prime paint and then undercoat?
thanks to all

 

[allcarfan]

i would sand out the rust...or blast it out...then wipe it with acetone and spray it with truck bed liner out of a can.

 

[5.0n66]

I would consider priming first a must....scrub down metal really well and then etch with metal conditioner then primer.... undercoating has alot of pinholes and it could get ugly pretty quickly since the undercoating has enough thickness to hold water in the pinholes up against the metal

 

[Platonic Solid]

Por15

The same way I did my Rear Wheel Wells.