I made a post a few months ago asking how to best paint a bumper with spray cans (and answers were helpful), but wasn't sure which route I was going to go and kind of got away from the project. Now I'm wondering how would I paint this bumper If I wanted to do it the right way? I am a beginner and the bumper isn't worth much as it's been damaged and repaired quite a bit.. A replacement bumper would be too much money for now and I would like to sell the car soon. I did want to do an at least okay job as I think the bumper can look decent If I wanted it to.

The bumper is plastic of course and black in color. I did sand most of it with 80 grit to get rid of paint chips and cracks.. I know now that that's overkill. I am lost as to what to do next though. There is still some black paint on part of it, so I didn't know if I needed to sand that or just sort of scuff it or what. I got 2 answers on that. Someone told me to hit the existing paint with 400 grit, someone else said to just scuff it and clear it. But I don't see how I would match it to the new paint I planned on putting on... I'm honestly just tempted to sand it off so I don't need to worry about somehow blending it with the new paint.. Although maybe that's easy..

Other than that I just am unsure of the steps. I guess I would go from 80 to 150-180 grit paper, then maybe 220, then prime it. Then sand and 400. Then either base coat or prime again and 600? Someone mentioned I might need a sealer.. Would I just spray that on top of the final primer I do, then BC? Also, can I use spray can primer or should I use spray gun stuff? I think I did sand through to the plastic on a few small parts, would that be worth adding adhesion promoter and would I put it on before the primer?

Only other thing I would wonder is what spray gun would be best for beginners and would it be hard to adjust the air settings? Biggest question is whether this is even really worth it.. I thought I may try using a spray gun just for the experience and to get a slightly better result than cans. But with runs, stuff I may run into, and extra money, Im not so sure. Sorry for the long post, not necessarily looking for every question to be answered, but just for a few thoughts. I tried looking online and this forum, but believe it or not I just can't find a solid guide. Ive only seen a few for bare plastic bumpers and they were sort of vague.

Did you look at the first blue highlighted post in this Fiberglass and Plastic category????
viewtopic.php?f=13&t=24768

Great link to post Darrell.

You will want to get all those 80 get scratches out first of all.
I suggest using 150 grit, then moving up to 180 or 220, but finish with 220 and feather everything out.

You do not need to remove the existing paint and strip it to bare plastic if some existing paint is good.

Unless the paint is only good on the sides and you only sanded with 80 grit on the face of the bumper.
I suggest sanding the whole thing with 220(after 80 grit scratches have been removed), then spraying adhesion promoter and spray primer.

Now, if the paint is good on the sides, then you can just prime the face of the bumper, sand the sides with 800 and blend your paint then clear all of it.

Serf, he said he has absolutely no idea how to blend, and he's doing it with spray cans, which have the lowest possible concentration of solids.

OP, you sanded a plastic bar with 80 grit? Your punishment follows and I can guarantee that you won't ever do anything so silly again.

First the good news. If you try and sand those scratches out by going through the grits you'll end up with holes in the bar before you get it smooth. So don’t.

If the bar has been repaired multiple times before then who knows what is under the paint; could be filler, spray bog, urethane repair, anything. So if the paint is sound on the top, leave it alone except for a light, but even sanding with P400 just to give a key for your primer. Don't try to sand the paint off and don't try to change the shape. If there are stone chips we'll come back to those later.

Where your repair is, or where you've already sanded with the P80, mix some fine filler and apply with a flexible plastic applicator so that you just fill all the scratches. You'll have to press firmly to get it in but don't overfill. You want to be able to still see the plastic in between the scratches. This way you won't lose the shape. Extend the filler just past the scratched area, using your applicator to feather the edges out. A tip: if the instructions for the filler say use 2-5% hardener, only use 2%. This way you'll have longer to work it nice and smooth over the area. Don't apply the filler outside in the sun. That's two tips - I'll send you the bill later.

Once the filler has set hard sand it back wit P180 on a firm but flexible block. Really, at this point you just want to knock down the ridges you left when spreading the filler and any high spots. Once done identify any low spots using a guide coat and light sanding. Clean it off and apply another light, thin coat of filler over the whole repair surface, again extending out just past where you were before. Sand again until smooth and uniform. Blow it off and fill any pinholes or minor imperfections, including any stone chips elsewhere on the bar, sanding down only until level. Now guide coat and sand again to check for any problems. Now sand with P240 and P320 to get rid of the P180 scratching, making sure that you feather out all the edges.

Prime, sand and paint.

As for your other questions, really, search the site. Answers are all there.