Mr and Ms Vdub wrote:light coat of rust paint seems to work fine, if not do small bits, prime then coat with any top coat rattle can, then move on, strip the whole lot, when your happy, then spray for the final time.
You have to be prepared to remove everything back to bare metal again or back to the filler if you put products on that are not compatible with the final topcoat product you will be using.
The two part epoxy primer is one of the best ways to protect as good as a topcoat and have a product that adheres very well. It is able to have any good products used on top of it. You can use body filler, polyester or primer on top of it. You must follow the manufacturers instructions, and that usually means a full sanding using 80# - 180# sandpaper before the next product going on top.
Also making sure the products used underneath are done properly will ensure the best final finish that will last.
Normally at work we
Abrasive blast
Do all metal repairs, metal finishing and lead fill work
Abrasive blast chassis and shell again
Two part epoxy primer and bake
Wait one week
Rub with 80 Grit
Filler work finished in 150#
Prime and polyester then bake
Rub and rub and rub finish to 320#
Putty then bake
Rub and rub and rub and rub finish to 1200#
Basecoat, topcoat, bake
wait one week
Rub with 1200# then 2000#
Buff, buff, buff, polish, polish,polish
One magic mirror finish with about 600-800 labour hours
There are a lot more steps involved that include inside panels, clean and strip wheels, cleaning lead work down to remove solder flux acid, painting separate parts like chassis, inside parts, partial panel assembly and gapping.