>>2936372
So enamel paint is great for metal, wood/basically any surface the product says you can use it on. It is hard, glass like, but that makes it brittle. While that is fine for static loads, it's a very bad thing for dynamic ones and you need to make sure you use a flexible primer. Furthermore, metal is an absolute bitch to paint and you need to make sure you get every bit of rust off. Chemical/electrolysis/sanding is a must and you can't wait too long or it will flash rust. Average Joe who doesn't know now "primes" after this step, which would normally be fine for an indoor cast iron whatever, BUT the problem is primer is also porous as to allow paint to adhere to it properly. This is find for wood, wood can breath, plastic doesn't give a shit either so long as it isn't the melting plastic type of primer.paint. Metal? Metal will SUCC the moist air in between the primer and start rusting again. What you needed first was a "sealer", preferably an epoxy based one which you would prefer because it's chemical dry and more durable as dynamic metal primer.
TLDR order of operations for cars :
>patching/(epoxy based) sealer to banish the rust from primers mouth breathing
>primer because pigment doesn't glue well to surfaces
>paint because primer can't be both and look good.
>(optional) Topcoat to protect the paint from your knuckle dragging, UV damage and give further sheen/deepness to the paint
And if you use "paint and primer in one" you and the can it comes in should be taken out and shot. Enamel also takes week-month to cure proper
>>2936463
And now you know what most cars come in ugly 80's remote colors now.
