Thread: Rocker panel surface rust repair?

My car has pretty solid rockers. Recently the underside of the rockers and the pinch welds have started to have paint peeling off them with surface rust forming. The drivers side rocker has a small spot that has bubbling paint that has came up along the side and you can actually see it below the door. I poked around the its all still solid metal.


What do you think about this? I ordered por-15, por-15 metal prep, and Por-15 top coat gloss black.

Should i sand down the rockers to bare metal, spray the metal ready, apply the por-15, and then apply the por-15 top coat? My car is already black so I don't really care about it matching entirely but I think it'll be close. I just want to slow the rust down. I also thought about just por-15ing the underside of the rockers and then fixing the bubbled paint with my touch up pen for now. When I say underside I mean the part of the rocker that curves down and faces the ground and meets the pinch weld so it wouldn't be visible unless you looked underneath. I think my paint code is wa8555. Its gm black.

Also, what's the best sanding tool to use? A sanding block for rusty metal? An angle grinder? Orbital sander? What kind of grit sandpaper should I use?

What year car?

I wish it was in everyones profile..hint, hint.
I am no body man, I spray the underside spots in spring and fall with Rustoleum industrial black and say f**k it.

Some of the rough stuff you will want some wire brush action. The metal prep is some good stuff. Did you order the cleaner to?
Anyway if it's a smooth spot, yeah you will want to sand it bare. The problem is you are not spraying, which would cover 600-800 grit I believe.
You also would want some primer action on bare stuff.

Get some wire brushes both nylon and brass or stainless.

Perhaps PM Idrivejunk.
He is very helpful and a full blown bodywork artist

My car was garage kept and hardly driven before I got it so it was in great condition. I was stupid and used the pinch welds several times to lift the car (until I got smart enough to just start lifting at the center of the car under the front and rear subframes). As a result the paint was chipped off and surface rust started to form on the pinch welds. You can check out what I did on this thread http://www.grandprixforums.net/threa...78#post1465278. Por 15 should work the same if not better. I hand sanded, but I had just a hint of rust. If you have a decent amount of rust I would just hit it with a power sander down to the fresh metal and prep and paint. I also used a paint that was very close to the color of my vehicle ("Bronzemetallist") and you can't even tell. So black should look fine.

The bubbling paint has me concerned, usually it only bubbles when it comes from the other side of the panel. Maybe you'll get lucky and sand it out and it won't be a hole, but there's always a risk. If your rockers are still good I highly recommend spraying some rust inhibitor or old oil/transmission fluid inside those rockers. And I mean flood them if possible. Here's a thread describing what I did to get to the insides of the rockers http://www.grandprixforums.net/threa...87#post1465387 I ended up spraying even more myself later.

Finally I tossed on some mudflaps to keep rocks from dinging up my rockers. I installed fronts and backs, but the backs are optional for this purpose. Here's some pics on this thread http://www.grandprixforums.net/threa...97#post1474697

I have tons of used motor oil lol. Would that work? I have tiny holes on the bottom of the rockers,, how the hell do I spray the insides? I have no compressor...

You'll have to rig up something. I just bought cans of the Corrosion Free and used that to spray inside. I know Lowe's sells Fluid Film for $10 a can and it's supposedly a decent rust inhibitor. At least that will spray out of the can for you if you can't think of anything else. One can should handle both sides.

Duplicolor universal black matches 8555 decent but looks browner in strong light, and the gloss level is obviously less. Clearcoating and buffing both help that. 80 grit on a dual action sander is the universally preferred prep method for bare metal. Paint Over Rust type products are not designed to work on bare steel. Epoxy primer is the only choice for pros on that. Get rid of the rust by using multiple applications of an acid based rust treatment product and wire brush. Rattle can etch primer allowed to flash dry and followed by black paint is the hobbyist-in-driveway choice I would prefer. Products not using a catalyst can't be expected to live long and are more easily damaged than the original finish so leave as much of that as you can. If you rustproof with oil, I hope you don't live on a dirt road or mind carrying around solvent and rags for when it migrates to the exterior finish.

Do you know if the por-15 metal prep spray will work on bare metal to help por-15 to adhere to it? I read somewhere that was one of the purposes of the spray. And I think I've seen YouTube videos where they spray it on clean metal without rust and then they paint the por-15 and the por-15 sticks on with no problem.

Best thing for treating and stooping surface rust is "OSPHO" (phosphoric acid), then paint as desired.

Already ordered por a few days ago. Has anyone ever used this stuff as a finish on rockers? I see cars all the time here with black coated rockers but can't find a pic online lol. I always see por on pickup truck rockers

I see people use all sorts of products on their rockers but never see por-15 unless it's when they're welding on new rockers and they use it on the insides. I never see it used as a finish on the outside. But I doubt it'll hurt anything as long as I use the por-15 top coat

i figure it may hold a few years and by then I'll know how to weld and I can just replace them once they get super rusty.