Paint prep question for new (raw steel) bumpers

So I decided to upgrade to some better bumpers for offroading and adding a winch. They both came in raw steel. I painted my sliders myself, so I figured I'd do the same for the bumpers. I have a question on how to deal with prepping the hard to get to and almost impossible to get to areas on the back sides. The sliders were easy since all areas were very accessible.
Any thoughts?

 

At-home prep: Drill with a small wire brush bit/attachment for as many places as you can reach. Sand blasting if you have the equipment (harbor freight has a bunch of junk for this). Hand sanding and elbow grease for everything else.

Commercial prep: Get it sand blasted. More money but best results. Just have to decide on the continuum from good to perfect where you are willing to go.

 

But how do you deal with the damned near impossible places to reach?
And what kind of abrasive is best for that useage.

 

Do the best you can, there really is no other answer. Sand blasting is going to take care of most places where even hands or tools can't reach. Blame the vendor for engineering it dumb if some areas are impossible, but don't lose too much sleep over it. You're gonna scratch it up and re-paint it again in a couple years anyways.

 

Sandblast,por15,and a good top coat especially if you live in the salt belt

 

I'm third on sandblasting & I went with powdercoating.

 

I'd use long-handled Q-Tips or rag-on-a-stick/coat hanger ( I double up the coat hanger to get a more rigid handle) with liberal amounts of acetone or mineral spirits to get to the hard-to-get places. Maybe use a spray bottle, too? Cover it with POR-15 or Steel-It metal coatings then paint to your liking. I used POR-15 and am satisfied with the results. You can leave some rust with POR-15. The acronym is for Paint On Rust. Painted it with Rustoleum rattle can. The paint gets salt blasted every winter and has to be redone in the spring, but the POR-15 is still going strong. It'll get scratched because nothing will stand up to rocks. I see no reason to get a powder coat. It'll just get scratched to bare metal anyway. Ask Spaz how hard it was to redo his powder coated sliders. I was quoted $600 to PC my minimal rear bumper.

 

Thanks!
I’m not worried about the outside, it’s the hidden inside areas I’d like to keep from rusting! I like the coat hanger idea!

 

The important thing is to get all of the grease and oil. POR-15 takes care of the rest.

 

you could try a product like this.
https://www.eastwood.com/eastwood-internal-frame-coating-plus-with-nozzle.html

i'm not entirely convinced that it's the most durable product, or will outlast any other finish. the main benefit is the included hose that should allow you to better coat the impossible to reach area's. and anything that's coated in something at least has a far lesser chance of rusting.

 

Like Dave @Stoney Ranger said, get all of the oil off first. I'm really happy with the Steel-It on my sliders, but you have to sandblast to get a rough enough surface for it to adhere well. I don't know what POR requires for surface prep besides being clean.

As for cleaning, Steel-It recommends Xylene. It ain't cheap, and the smell will kill ya, but it does work well. Oh, and it's probably just as flammable as mineral spirits or acetone.

I used Herculiner (bed liner) on my front bumper. The roll-on shyte was terrible to work with (holds well, though), the spray seems to be holding up well. Fleet Farm sells it, Farm and Fleet might, Menards, Ace Hardware, Tractor Supply, and several auto parts suppliers.

We'll have yer head spinning in no time!

edit: The Herculiner smell will knock you on your azz too!

 

I've had tons of luck with Ace Hardware 's self etching primer

But the POR15 approach seems to be the most top notch

 

The POR-15 "kit" comes with a degreaser and a metal etch to give the coating a surface to "bite".