good roll-on paint?

Is there a good roll-on paint, such as using to paint armor? (raw steel)
last time I painted a bumper was horrible.
spray cans of primer, paint, and clear. 90% of the paint went into the air, not on the bumper.
It took forever.
And was hard to get into nooks and crannies on the inner side. Whereas a brush might work better.

Only concern about brushing is it might leave streak marks while spray doesn't
and if one side is brushed on too thick and then left to dry on card board, it could leave run marks either on that side or on the backside if it manages to slowly drip over.
meaning the finish on spray *might* look better.
Paint seems better than powder coat because it's cheaper and can be touched up when scratched.

for now, planning to paint a tailgate reinforcement. Then maybe one day sliders.
Might take a risk and buy any random cheap quart or so of satin black paint from Home Depot and some brushes, including mini roller

Seems a lot easier than huffing paint all day getting in your lungs, eyes, on hands, clothes, etc

 

Hmm I wonder why you had so many problems with the spray paint.
We’re you painting in the wind?
I love to spray paint.
I’m sure you could roll on some rustoleum

 

POR15 levels out pretty well but requires sandblasting to stick well (they have a product that they say works as a primer, but it doesn't). It is also not UV stable.

I also have used Rust-oleum oil based enamel. It too sticks better to sandblasted metal.

Both are quite thin, make a mess if put on heavy, but level out pretty well. Also, they both require multiple coats.

Edit: I replaced about 5ft of frame on an Airstream. I had the rails blasted before I welded them in. I painted with POR15 using 3 coats with cure time in between. After it was done, we decided to add outriggers to provide support to the bathroom (shower location changed in plans) and I had to use a grinder to get the paint off.

 

I just painted my bumper using rustoleum industrial high performance protective enamel. All of your fears will come true, but I kinda knew that going into it and expected it. After all, it's an offroad bumper. That's why I didn't care. I used brushes and sponges to paint mine, you might do better with alot of patience and a roller. By patience I mean:the time and willingness to do a number of thin coats. In the end, mine looks like a painted industrial handrail in semigloss black, but I like it. It'll take some abuse, and touching up couldnt be more simple. It's not perfect, but I was pressed for time, and expected it to come out as it did. It's also cheap, tough, and readily available at lowes and home depot. I paid a little less than $9 per quart, and a quart goes further than 4 rattlecans do. Just my .02

 

I painted my US Offroad winch mount with rattle can raptor liner but only the show faces. Everything else was brush on black rustoleoum. I think if I thinned it out a little bit the paint would level better but no one will ever see the part I did by brush

 

I used a rubber chip infused, paint-on bedliner for sliders (previous vehicle). Worked great.

You have to be OK with the textured look for this. I wanted the traction since they doubled as steps, and it looked/worked excellent.