Help with DIY repaint of lower front clip

[JMak97008]

I have a 2006 300C SRT8. The car has a lip on the bottom of the front clip. When I bought it, the underside of that lip was pretty scratched up from being pulled over parking blocks or rubbing pavement when going down a steep drive into a roadway. Out on the ends, the damage isn't bad with mostly cosmetic scratches. In the middle, though, some heavier scratching even down to primer.

Im unwilling to have the whole front bumper repainted to address this and this is technically under the car, so I thought to tackle it on my own. I've bought some Duplicolor Perfect Match paint and clear for my specific color. I've thought that I would wash and dry the area and then, for my first time, wetsand by hand the area, then spray, clear, and throw some wax on it.

Regarding the wetsanding, I thought I'd use a block of some sort and work my way up from 1000 to 1500 to...and this is where my planning fell apart. Is 1000 too aggressive or not aggressive enough? I think I really just want to clean up the scratches, i.e., take their edges off and scuff up the panel to accept the paint,since again this is underneath.

I'd appreciate any advice on the grit I should use and any other suggestions.

I'll post some pics after completing the task this weekend.

[2black1s]

If I understand your situation correctly, it sounds to me that 1000 grit is not nearly aggressive enough.

I'd be starting with something like 220G to remove the bulk of the scratches to whatever level you are satisfied with, then work my way up. Probably 320G, then 400 G, and maybe 600G.

If you are painting over it there is no need to go any finer than 600G. Even stopping at 400G is appropriate for what you're doing.

I'd also use a sponge type backing, not a sanding block, to perform the sanding operations. Many urethane bumper covers and the like are just not flat enough and are too flexible to benefit from block sanding.

[JMak97008]

If I understand your situation correctly, it sounds to me that 1000 grit is not nearly aggressive enough. I'd be starting with something like 220G to remove the bulk of the scratches to whatever level you are satisfied with, then work my way up. Probably 320G, then 400 G, and maybe 600G. If you are painting over it there is no need to go any finer than 600G. Even stopping at 400G is appropriate for what you're doing.

Thanks for the advice.

I was hoping I was descriptive enough. Some of the same scratches are scrapes and some are minor gouges. Their edges look like those on some scratches your see on interior plastic where they're raised. I want to knock those down and get the surface prepped for that duplicolor perfect match spray paint.

Do you think dry sanding or wet sanding would be the right approach?

[2black1s]

Thanks for the advice.

I was hoping I was descriptive enough. Some of the same scratches are scrapes and some are minor gouges. Their edges look like those on some scratches your see on interior plastic where they're raised. I want to knock those down and get the surface prepped for that duplicolor perfect match spray paint.

Do you think dry sanding or wet sanding would be the right approach?

Dry or wet? Either will work but wet sanding provides many advantages.

If sanding dry the paper can clog and that will result in a less uniform surface. I only use the dry approach for very light sanding of small areas.

Wet sanding is the "standard" and most likely the correct approach for your situation.

The only advantages I can think of to dry over wet are: A little less of a mess; and you can see your progress in real time. When sanding wet, you cannot see your progress as well as you work. You have to clean and dry the area to get the whole picture.

[2black1s]

One more piece of information for you to consider...

The DupliColor paint that you have is most likely acrylic lacquer (most touch-up paints are) which is not very flexible and therefore not the best choice of paint for a flexible panel. It will work but it may develop cracks over time.

I'd consider checking with a body shop or an automotive paint store that can furnish a paint recommended for flexible bumpers.

[Rsurfer]

One more piece of information for you to consider...

The DupliColor paint that you have is most likely acrylic lacquer (most touch-up paints are) which is not very flexible and therefore not the best choice of paint for a flexible panel. It will work but it may develop cracks over time.

I'd consider checking with a body shop or an automotive paint store that can furnish a paint recommended for flexible bumpers.

:iagree: I would also consider removing the lip for ease of prep and spraying.

[JMak97008]

Thanks, guys. I'm taking the car to my mechanic on Saturday and he'll be putting it on a lift. My plan of attack was to, while up on the lift, tape-off the area, hit the area with 220, 320, then 400g paper, hit it with some filler primer, sand it, spray color, and then clear it. I think this will be sufficient as the entire area is under the car and I'm really just trying to clean it up.

[2black1s]

Good luck.

Let us know how it turns out.

[JMak97008]

So, I went with an abbreviated process and skipped the filler primer. I know that lower lip will get scraped up, again, so I just went with wet sanding with a medium grit block, then painting and clearing with Duplicolor's perfect match color and clear. I'm happy with the results despite not fully removing all the scratches or filling them in. I think now, I'll just hit it with hand-applied Megs UP and then UW.

Before:
https://i.imgur.com/ZCnZ34a.jpg
https://i.imgur.com/7SG8pNa.jpg

After:
https://i.imgur.com/dIO0wMP.jpg
https://i.imgur.com/nVA85RP.jpg