I have (and have had) a slew of cars that have needed touch ups, to complete repainting and so far, my experience with spray cans has not been very good. Most recently, I used Rustoleum Auto sandable primer on the fender of my 83 GL and on the hood of my 77 Mustang. This was only for rust prevention, to be finished this summer. This was last fall and already both have started flaking off. I noticed on the hood of the mustang (Which isn't even being driven. Just snowed on.) several flakes of paint are gone and the bare metal underneath has started to rust again. I sanded very well before applying the primer. I did only one coat since I will be finishing it in the spring.

 

Any ideas on what I did wrong? Or is there a better spray paint out there to use on a car?

Primer coats provide NO protection from rust you must cover with a paint coat to seal out air. If youre going to touch up later just use andy spray PAINT to cover the prime.

Doesn't quite make sense to me. My impression was the primer paint adheres better to the metal so the enamel or whatever paint will have a better surface for the final painting. Am I mistaken?

Primer does stick good.

But it provides no real weather protection. Needs some kind of top coat to seal it or it will actually act like a thin sponge layer.

At least thats how it's been explained to me by many different people. Some of them very good body repair gurus.

Primer does stick good.

But it provides no real weather protection. Needs some kind of top coat to seal it or it will actually act like a thin sponge layer.

At least thats how it's been explained to me by many different people. Some of them very good body repair gurus.

 

Gotcha. I'll get some good Krylon or something on top then. Thanks!

krylon is fairly good paint, but it will be cut down by gasoline if you are paintingnear the fuel cap.

 

the orange and white are krylon and the balck is the generic wal-mart rustoleum wannabe "color place rust control stuff"

 

so far with spray painting many of cars i have found the plasti-kote duplicolor to be the most durable.

 

you may want to consider a rust stopper such as por-15. i myself have never used the stuff, but i got ahold of a product calld 'rust-n-me' or something like that i scored from the shop at u-haul. it looks like washer fluid. i am prepping the rx with it now, just brush on and it chemically dissolves the rust and seals it.

 

the purpose of this product is to apply to rusty truck bumpers, and then wipe it off, it sticks to the rust but does not affect any paint, thus wiping off clean.

if you are aware, there are about 3 things to learn here in this thread:

1. there is primer

2. ther is primer/sealer

3. and there is paint

 

for things to work out desirable, you must use 2 and 3 pretty much in the same week. 1 is just plain bad and will result in rust, lifting, bubbling, etc.

 

too many "shoddy" or "do it yourselfer autobody" will do number 1. Sorry...you will learn just ask ANY prof body repair guy, i mean ANY one that is a pro.

most of the problem is surface prep. what grit paper did you use and did you use a surface prep solvent just before you primed ??? oils from sanding and your hands can affect adhesion. if you have bare metal you can try an acid etch primer, and wet sanding between coats with 600 grit wet paper, even if you grind all visiable traces of rust it almost always comes back.

i myself have never used the stuff, but i got ahold of a product calld 'rust-n-me' or something like that i scored from the shop at u-haul. it looks like washer fluid. i am prepping the rx with it now, just brush on and it chemically dissolves the rust and seals it.

 

the purpose of this product is to apply to rusty truck bumpers, and then wipe it off, it sticks to the rust but does not affect any paint, thus wiping off clean.

 

Sounds like phosphoric acid. Reacts with rust to form iron phosphate, which is pretty durable.

Sounds like phosphoric acid. Reacts with rust to form iron phosphate, which is pretty durable.

 

the smell and the reaction is similar to that of high strength toilet cleaner, like the kind you mix with foil in a pop bottle to make works bombs

the smell and the reaction is similar to that of high strength toilet cleaner, like the kind you mix with foil in a pop bottle to make works bombs

Yep, that would be phosphoric acid.

 

Check with the "Rat Rod" guys. What looks like primer on thier rides is actually satin black paint. Primer WILL rust through quickly. POR-15 won't, It's not cheap, but it will protect the metal, until you get to painting it.

Epoxy-based primer WILL keep the rust out for quite a while, sometimes years. But there are two things to remember;

1) You have to grind away ALL of the rust before you apply the primer.

2) It is a 2 part primer and it has to be sprayed with a spray gun.

That being said, go with the POR15 if you want a finish that is tough, easy to apply, easy to prep, and good looking. They also make it in different colors, and some types are not UV resistant and will break down in the sun.