Self etching (also known as self etch) primer is the stuff to use. It is acidic and etches into the metal for a strong bond. Other primers can be scraped or chipped from the metal.
Apologies for my English - I have been learning another language for the lest 2 weeks and can't seen to write in my first language now.
Yes I would agree there, Etch Primer is the best way to go, I've been using it on all my projects for the past 20 years or so.
The best ones I've found use both a Paint and an Activator - they are quite thin when mixed and are best sprayed on in 2 or 3 coats. The first coat will be barely visible. One thing that is very important - you must use an Air Fed Mask when spraying, this stuff is bad for you if you breathe it in.
just remember primers are not water proofing.
if fact they soak up water.
i just blast a aerosolve paint over primer to hold it.
use white as its nutural
JayKay Paint over primer.... with the not intended color you want the auto to be, Is that what you are saying? Primer soaks up as you say to make a better bond with the paint. Because the paint will only stick on the surface it's applied to. and a painted surface even sanded is not as good as a primered surface, because primer will soak into paint if sanded correctly, then letting the paint soak through the both of them.