Repairing scratch - Is clearcoat sufficient? (Fingernail does not catch)

[Bornin1992]

Hi, all,

After work I came out to see someone scraped my rear bumper and (not surprisingly) did not leave contact information.

I cleaned the area with lacquer thinner, clayed it, and was able to via wet sand fix all of the damage done except for the vertical scrape. However, because my fingernail does not catch it, I am unsure how to proceed. The vertical scrape is basically level with the surrounding paint such that I could not imagine adding a singular layer of basecoat (let alone a clear-coat layer) without it being significantly more raised than the surrounding paint. Does this mean clear-coat is sufficient?

I have in my arsenal the following equipment: Griots Garage G9, Meguiar’s Ultimate Compound, D300, and M105, as well as Griot’s Garage Fast Correcting Cream and Correcting Cream. For pads, I have Lake Country SDO’s in Orange and Blue, and Lake Country flat yellow pads, and Meguiar’s microfiber cutting disk.

I am uploading some photographs, one of which was taken before polishing after wet-sanding.

Any suggestions would be most appreciated! It is a metallic paint, and I am hopeful I can get away without using base-coat

Thanks!

[dgage]

Didn’t see your pictures but you could use some paint or clear to build up a bit and then polish flat. However, be very careful on a bumper as the plasticizers added to the paint for covering plastic make the paint thin and susceptible to heat damage. So work carefully with any polishing you do and remove the pad often to ensure no heat builds up.

The other thing I’ll say is sometimes it is best to just leave it good enough as messing with it more could make the damage more noticeable than it already is.

[Bornin1992]

Didn’t see your pictures but you could use some paint or clear to build up a bit and then polish flat. However, be very careful on a bumper as the plasticizers added to the paint for covering plastic make the paint thin and susceptible to heat damage. So work carefully with any polishing you do and remove the pad often to ensure no heat builds up.

The other thing I’ll say is sometimes it is best to just leave it good enough as messing with it more could make the damage more noticeable than it already is.

Thanks for your response. I forgot to upload the photos when I posted the thread: are you now able to see them? I just don't know if clear-coat is good enough, and, unless I am misunderstanding the process, if I try first with the clear-coat and it doesn't work, I'd have to remove that clear coat to add the touch-up paint...No?
And because it's already basically flush, not sure how to build it up? Apologies if my response comes across as rude as I think it might be, not my intentions at all.

[2black1s]

Hard to tell from the pic but I think you're talking about the scraped edge. I can't tell if what's left is the base coat or the substrate. If the base coat is still intact, then clear only would be the appropriate repair, but if the substrate (or primer) is exposed then you need some color before applying the clear.

Easiest way to test would be to wet the area with some mineral spirits. The wet mineral spirits will give you a preview of what the clear will look like and from that you will be able to determine if you need to add some color first. You could also just try the clear and if you don't like it wipe it away with solvent before it dries.

[Bornin1992]

Hard to tell from the pic but I think you're talking about the scraped edge. I can't tell if what's left is the base coat or the substrate. If the base coat is still intact, then clear only would be the appropriate repair, but if the substrate (or primer) is exposed then you need some color before applying the clear.

Easiest way to test would be to wet the area with some mineral spirits. The wet mineral spirits will give you a preview of what the clear will look like and from that you will be able to determine if you need to add some color first. You could also just try the clear and if you don't like it wipe it away with solvent before it dries.

Thanks for your response. I will purchase some mineral spirits, apply it to the area, and post a photograph. Also, I have circled the scratch in question, though I suspect you were correct.
Meanwhile I have two questions:
First, I am slightly confused (and perhaps my confusion will be resolved after applying the mineral spirits), about how will applying the mineral spirits help me determine if I need to add color first. I have referred to your article Discerning Paint Chip Touch-Up, and, while it is not written for scratches, I assume the similar process will be followed for general touch-up applications, meaning I will need to wet-sand. Obviously I cannot wet-sand with the mineral spirits - will not the scratch remain the same, just slightly glossier? Again, it might be my question will be answered after trying it.

Second, is it possible this scrape could be corrected via wet-sanding with a lower grit (say 600?) sandpaper? I used 2000, and it did nothing. I just really am confused with this one because it basically is flush with the surrounding area. I mean I can kind of tell a difference, but I really think that is because I can see where the damage is and am trying to feel a difference. Put otherwise, I do not think a blind person, without knowledge of any damage, could feel a difference.

[2black1s]

Meanwhile I have two questions:
First, I am slightly confused (and perhaps my confusion will be resolved after applying the mineral spirits), about how will applying the mineral spirits help me determine if I need to add color first. I have referred to your article Discerning Paint Chip Touch-Up, and, while it is not written for scratches, I assume the similar process will be followed for general touch-up applications, meaning I will need to wet-sand. Obviously I cannot wet-sand with the mineral spirits - will not the scratch remain the same, just slightly glossier? Again, it might be my question will be answered after trying it.

Applying the mineral spirits will provide both gloss and clarity to the defect. The clarity will allow you to see the true color of the affected area. From what you see you should be able to determine if you will need to add color before the clear. As far as wet sanding goes, you don't really want to do any sanding until after you apply the clear coat.

When all is said and done with the Mineral Spirits, yes, the original defect will remain the same. You are only using the Mineral Spirits as a wetting agent to provide the clarity and gloss needed to determine whether or not color is needed. Once the Mineral Spirits evaporates the defect will remain exactly as it was previous to the application.

Like you said, I think once you do it you will see what I'm talking about.

Second, is it possible this scrape could be corrected via wet-sanding with a lower grit (say 600?) sandpaper? I used 2000, and it did nothing. I just really am confused with this one because it basically is flush with the surrounding area. I mean I can kind of tell a difference, but I really think that is because I can see where the damage is and am trying to feel a difference. Put otherwise, I do not think a blind person, without knowledge of any damage, could feel a difference.

Is the paint actually chipped or scraped away? Or are you maybe dealing with some transfer, or a smudge/slight abrasion to only the surface? If that is the case, I would try some compound by hand. Stay away from wet-sanding unless it's absolutely necessary.

When you say that you can't feel it, that indicates to me that you are dealing with some type of minor surface blemish. Again, if that is the case some hand compounding should correct, or at least improve, the defect.



Without seeing the defect in person, I don't really know what else to add.

[Bornin1992]

Applying the mineral spirits will provide both gloss and clarity to the defect. The clarity will allow you to see the true color of the affected area. From what you see you should be able to determine if you will need to add color before the clear. As far as wet sanding goes, you don't really want to do any sanding until after you apply the clear coat.

When all is said and done with the Mineral Spirits, yes, the original defect will remain the same. You are only using the Mineral Spirits as a wetting agent to provide the clarity and gloss needed to determine whether or not color is needed. Once the Mineral Spirits evaporates the defect will remain exactly as it was previous to the application.

Like you said, I think once you do it you will see what I'm talking about.



Is the paint actually chipped or scraped away? Or are you maybe dealing with some transfer, or a smudge/slight abrasion to only the surface? If that is the case, I would try some compound by hand. Stay away from wet-sanding unless it's absolutely necessary.

When you say that you can't feel it, that indicates to me that you are dealing with some type of minor surface blemish. Again, if that is the case some hand compounding should correct, or at least improve, the defect.



Without seeing the defect in person, I don't really know what else to add.

Thanks! Here are some photos of the defects:
Before mineral spirits:


After mineral spirits:
After:


I do not think it is a transfer, but I nevertheless tried using a LC Orange pad by hand with GG Fast Correcting Cream without success. What really has me scratching my head is the fact it is basically level with the surrounding area. Is it possible the paint could be removed and it still be level with the surrounding area, i.e. the fingernail does not catch?

Is it possible to use clear-coat on its own, and if it does not work, remove that clear-coat and apply colour? Or would that just make it still more complicated.

[2black1s]

I do not think it is a transfer, but I nevertheless tried using a LC Orange pad by hand with GG Fast Correcting Cream without success. What really has me scratching my head is the fact it is basically level with the surrounding area. Is it possible the paint could be removed and it still be level with the surrounding area, i.e. the fingernail does not catch?

Yes that is possible on an edge like you are dealing with if the paint was removed by abrasion rather than a scrape. A scrape would typically result in chipped away paint and would exhibit a distinct edge at the perimeter of the defect, whereas an abrasion could leave a smoother featheredge.

Is it possible to use clear-coat on its own, and if it does not work, remove that clear-coat and apply colour? Or would that just make it still more complicated.

Again yes. That was one of my suggestions in my first response.

[Bornin1992]

Yes that is possible on an edge like you are dealing with if the paint was removed by abrasion rather than a scrape. A scrape would typically result in chipped away paint and would exhibit a distinct edge at the perimeter of the defect, whereas an abrasion could leave a smoother featheredge.



Again yes. That was one of my suggestions in my first response.

Yes, indeed. I was wondering, though, if I could try with clear coat, let it dry, wet sand to level, and if not happy with results, remove the clearcoat and add some colour.

[2black1s]

Yes, indeed. I was wondering, though, if I could try with clear coat, let it dry, wet sand to level, and if not happy with results, remove the clearcoat and add some colour.

Not likely... You should have determined if color is needed earlier in the process. That's what the wet mineral spirits suggestion is for... It will tell you.

Also, earlier when I said you could use the clear as an alternative to the mineral spirits and wipe it away before it dries if you're not happy with the result, I failed to mention that that is really dependent on the type of clear you're using. If you are using lacquer, which most touch up paint is, this is not a great option. It only works well if you are using an enamel or urethane clear.