I'm fixing up a 3 point hitch for my tractor. Over the years it's developed little spots of rust and the rest of the factory paint has faded slightly (grey). I soaked everything in evaporust and all of the rust is gone. Wire brushed where the rust was to remove any loose paint. So I am left with 95%+ solid factory paint and a bunch of bare metal spots throughout. The majority of the spots are 1/8" or less.

So should I prime all the pieces and if so will there be any issue with the primer adhering to the factory paint. I'm just using rattle can rust oleum, probably the "clean metal primer"

 

Absolutely you want to prim, paint is a top coat, primer is the base coat that protects the metal.

No issues with primer on paint.

Try the rusty metal red primer, for all my auto fabrications that is what I use and it holds up well for a rattle can material!

 

I agree - it's best to use a primer. I also like the rusty metal primer although most any rattle can primer will do the job. If the finish paint is going to be grey I'd get a grey primer as it won't be as hard to cover. As long as the existing paint has been scuff sanded there shouldn't be any issues with adhesion.

 

If you used a rust conversion coating you must use some type of oil based paint on those converted areas. For farm implements I usually use spray can paint. If it's a big area and I have time I will prime. Otherwise I just top coat and put it to work. Still priming is a good idea. Some implements are powder coated and you can get better adhesion by scuffing the area so the primer/paint can get a mechanical grip.

 

Thanks, I've scuffed everything and will coat everything with primer in order to make sure all the little dots where rust once was are covered. I've used the rusty red before, usually where I have existing rust and don't want to prep too much. The Evapo Rust pretty much eliminated all rust. Rustoleum "clean metal primer" says it's for clean or slightly rusted metal so I'll use that. Thanks for the feedback.

 

Bare wood and bare metal should always be primed.