What's your favorite metal primer?

[bdosborn]

I need to prime and paint a steel tubing frame for the van bed. What's everyone using, or is a rattle can good enough? I think I used Rust Bullet on the trailer frame and it's held up really well but it's stupid expensive.

Bruce

[Capebuild]

When I primed my frame I used Cold Zinc Galvanzing spray from Rustoleum (rattle can).... where I've scratched off the black paint the zinc primer holds up pretty well. I'm happy with it.
John

[bdosborn]

Interesting, I never would have thought of that kind. Is there any compatibility issues with any topcoats?

Bruce

[MickinOz]

I'm a big fan of zinc rich primers/cold galvanising paints.
I've never had an issue with topcoat compatibility.
I will say though, I prefer to use brush-on zinc rich paints.
This is because the spray cans block so easily between uses.
I have found a small improvement, though.
You know how you turn a spray can upside down and operate the nozzle until it runs clear before you put it away?
With spray cans of cold galvanisng paints/primers, when you've done that, and the nozzle is clear, don't turn it back the right way up. Fit the cap back on, and store the can nozzle down. The zinc can't get into the delivery system and block it when you do this.
Don't turn the can the right way up until you've given it a good shake for the next use.

[tony.latham]

I used a self-etching primer from a rattle can on the last couple of trailers. I think it's good stuff for metal.

https://dfarq.homeip.net/self-etching-primer/

I've got a 2 x 72" belt grinder project going and I'll use it for that.

Tony

[featherliteCT1]

I used self etching primer on a piece of metal that still had patches of original paint on it in places. I sanded but did not remove the patches of old paint and then covered the entire piece with the self etching primer. I then painted the primed piece with an exterior coat of paint. The exterior coat did not adhere well to the areas over the patches of original paint.

The article linked to says ”The caveat with this type [of primer] is that you need to remove the old paint.”

Now I know why my paint failed.

[bdosborn]

I'll give the acid etch a try. I'm using all bare metal so old paint wont be problem. Thanks everyone for the tips.
Bruce