Buffing/polishing to blend scratch repair

[stoopid]

As some have read, I had an incident last week leaving a scratch in my fender. Details can be found here: Why we can't have nice things

The scratch is more like a knife cut, very thin and deep. Maybe 7" long. I can barely feel the scratch under my finger nail, but it's definitely through most if not all of the clear coat. It's also fairly dark inside the scratch, I did several runs of cleaning with a microfiber and even a soft toothbrush using 70% isopropyl.

After drying I applied my touchup pen, then polished using my harbor freight buffer and some polishing compound I already have. It worked so well it removed all the touchup paint (this was after 36 hours of drying and only light pressure).

So I cleaned the scratch again, applied another coat of the touchup paint and will be waiting 3 full days before my next attempt. I don't want to keep messing with and reducing the depth of the clearcoat so I'd like to get the repair with this next pass.

Now my question: what's the best strategy to blend this? I really don't care about color correctness obviously, it's not happening without paying a shop. I'd just like to get the surface blended so it's not obvious when looking at it in sunlight. I've never done it, but I'm wondering if careful wet sanding might be on order?

Pics of the touchup paint filled crack attached. The touchup repair looks better in person than the photos would indicate, I took the absolute worse angles I could find for purposes of showing the issue.

 

[MerlintheMad]

Wet sandpaper is risky as can be. You'll go right through to the metal/plastic before you realize it. Blending, I am afraid, is not really a viable goal with a specific touchup like this. I have a few. The worst one ended up under PPF, because I simply cut bait and said, "That's as good as I can do". The spot received several attempts (it was a rock that both my son and I saw coming, and bounced near the right headlight, clear through to the black plastic: car wasn't even three weeks old, and that was it's first road trip): each time I applied the touchup paint then waited a day or more: I never could make it blend, and what's more, sanding seemed to darken the touchup paint making it stand out even worse. Finally, that last time, I got enough touchup paint on a card to get a 1/4" wide artist's brush filled and made a single pass over the spot: now, as I said, I have a permanently preserved blemish, a reminder that "nothing in life has any business being perfect". The rest of my car is almost perfect.

 

[stoopid]

Wet sandpaper is risky as can be. You'll go right through to the metal/plastic before you realize it. Blending, I am afraid, is not really a viable goal with a specific touchup like this. I have a few. The worst one ended up under PPF, because I simply cut bait and said, "That's as good as I can do". The spot received several attempts (it was a rock that both my son and I saw coming, and bounced near the right headlight, clear through to the black plastic: car wasn't even three weeks old, and that was it's first road trip): each time I applied the touchup paint then waited a day or more: I never could make it blend, and what's more, sanding seemed to darken the touchup paint making it stand out even worse. Finally, that last time, I got enough touchup paint on a card to get a 1/4" wide artist's brush filled and made a single pass over the spot: now, as I said, I have a permanently preserved blemish, a reminder that "nothing in life has any business being perfect". The rest of my car is almost perfect.

I've heard and seen demonstrated using needles and other pointy ends to dribble paint into the crack as you describe, but certainly that's more skill than my hands and 47+ year old already diminished eyes can accomplish.

As a side note, I was just put in contact with a professional in the body shop industry who said just like you to not wet sand for the exact same reason. He said I could 'wool' buff and then polish, but warned that melting the clearcoat is also tricky for similar reasons to wet sanding - it's easy to run through that thin couple mils of clearcoat.

 

[Landshark]

try some Meguiars Ultimate Compound, then the polish ... the compound is a bit more aggressive than the polish, but not too bad. maybe even start by hand, then machine if you need to.

 

[MerlintheMad]

try some Meguiars Ultimate Compound, then the polish ... the compound is a bit more aggressive than the polish, but not too bad. maybe even start by hand, then machine if you need to.

I have Meg's rubbing and polishing compounds. In addition to sanding darkening the touchup paint, I experienced the same thing when going over the repair (touchup) with these products. I think that the touchup paint Kia sells (can't speak for Dr. Color Chip or other products) isn't really the same thing as the baked on paint of the factory: it is more like an acrylic and never gets entirely hard: so, when you rub it with anything at all, it picks up whatever is contacting it and changes color.

 

[stoopid]

I appreciate the ideas and input thus far. I'm going to try taping off the affected area, very close to the edge of the touchup paint, and mild go over it with the buffer. Then I'll polish lightly by hand and call it a day. Taping off will help reduce the wear on the surrounding clear coat and allow me control over the area I need to focus blending. That's the plan at least.

 

[AtomicGTL]

Not sure which touch up pen you're using but the original kia one is doodoo.

Go for scratcheshappen.com and get you those primer/basecoat/clearcoat little bottles with the tiny brushes. Easier to navigate than the pens imo.

 

[AtomicGTL]

I've heard and seen demonstrated using needles and other pointy ends to dribble paint into the crack as you describe, but certainly that's more skill than my hands and 47+ year old already diminished eyes can accomplish.

As a side note, I was just put in contact with a professional in the body shop industry who said just like you to not wet sand for the exact same reason. He said I could 'wool' buff and then polish, but warned that melting the clearcoat is also tricky for similar reasons to wet sanding - it's easy to run through that thin couple mils of clearcoat.

I think once you do apply all the appropriate measures (clearcoat/basecoat etc) and waiting a bit of time then getting a professional to buff/polish lightly the area may even out the situation. Doing it soon may strip again the process.

 

[stoopid]

I think once you do apply all the appropriate measures (clearcoat/basecoat etc) and waiting a bit of time then getting a professional to buff/polish lightly the area may even out the situation. Doing it soon may strip again the process.

That's exactly what happened, the touchup paint is junk. I'm going to get some clearcoat paint at autozone and call it a day.

 

[SRV]

The scratch is more like a knife cut, very thin and deep. Maybe 7" long. I can barely feel the scratch under my finger nail, but it's definitely through most if not all of the clear coat. It's also fairly dark inside the scratch, I did several runs of cleaning with a microfiber and even a soft toothbrush using 70% isopropyl.

You can remove the scratch by wet-sanding, and here's how: