Wet Sanding Reveals Strange Ovals in Paint?! (Pics Within)

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DownFlyer

New member
OK I'm really stumped on this one.



I was following the Paint Clinic article to fill in a stone chip on my hood. Today I was wet-sanding down the overfill area with 2000 grit sandpaper.



Here is the chip before re-filling it:











Now I wet-sanded and these weird ovals appeared near the chip. Is this a remnant of some old chip-repair from the previous owner? I am really confused.







The only thing I can think of is that I removed the old touch-up paint from the chip using a very small amount of lacquer thinner so I could re-start it properly after reading the Paint Clinic article. I'm pretty sure that I didn't dab it anywhere else. Though I don't even know if that could cause something like this.



What the heck is going on here? Did I mess up??
 
trig said:
It looks like you sanded way too much. Are you sure you used 2000 grit?
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Without a doubt, I only bought 1500 and 2000 grit. I re-checked and it is definitely 2000 grit. The sandpaper itself is almost smooth like paper.
 
the smaller greenish ring looks to be the same color as the green primer at bottom of the chip. The other ring could be where the clear and base coat meet..



My vote is that u wet sanded into the primer. Did u buff it yet?



Why did u wet sand such a large area? If I filled that chip I would only try to wet sand the chip.
 
It could be the second layer of a previous touch up, but if you were to purposely sand through your paint, that's exactly what it would like.



Consider it ruined and try polishing it. Maybe you and I both are completely wrong...If you did sand to far, you can't screw it up much more by trying to buff it out again.









Edit: Looking at the pictures some more, I'm really leaning towards you pusing to hard with your middle finger as you were trying to sand it, but like the poster above me mentioned, that's way to much to sand in the first place. I would sand no more than 0.25" past the EOP of the chip.
 
David703 said:
the smaller greenish ring looks to be the same color as the green primer at bottom of the chip. The other ring could be where the clear and base coat meet..



My vote is that u wet sanded into the primer. Did u buff it yet?



Why did u wet sand such a large area? If I filled that chip I would only try to wet sand the chip.
Click to expand...



That ring really isn't so green ... it's a trick of the camera.



I have not buffed it yet.



The chip is actually pretty small and honestly I was a little clumbsy with the sand paper and the lighting was poor so I did not accurately see the right spot. I probably should have removed the hood deflector first so I could get at it more easily.
 
trig said:
It could be the second layer of a previous touch up, but if you were to purposely sand through your paint, that's exactly what it would like.



Consider it ruined and try polishing it. Maybe you and I both are completely wrong...If you did sand to far, you can't screw it up much more by trying to buff it out again.









Edit: Looking at the pictures some more, I'm really leaning towards you pusing to hard with your middle finger as you were trying to sand it, but like the poster above me mentioned, that's way to much to sand in the first place. I would sand no more than 0.25" past the EOP of the chip.
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Fair points, though I'm wondering why it was such a nice round oval. If I sanded into the primer, then wouldn't it have been a different and much more rough shape?
 
DownFlyer said:
Fair points, though I'm wondering why it was such a nice round oval. If I sanded into the primer, then wouldn't it have been a different and much more rough shape?
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Not necessarily. Judging by the color of the car (I don't know what the car is, but I haven't seen a *new* color like that in forever), I'd say it's what - 10-15 years old? If I'm right, did you measure the paint thinkness before hand? Painting several years ago is nothing like it was today. Paint thickness could have been a mess way before you started tearing into it.



My honest-to-goodness assumption from looking at the shape of the entire part you sanded, is that you had your pointer finger over the chip, as a control finger, and you were unintentionally using too much pressure with your middle finger. Rub your hand like your sanding with it on your desk, trying not to put too much pressure down with your pointer finger and you'll see what I mean. This is why you sand very, very little in cases like that, and use like no pressure, especially since the paint you intended to sand down was fresh and most likely softer than the original.



I'm no pro, hell I'm not even an amature, but I've screwed up similar projects (thankfully no cars) and that's exactly what it looks like.





It may still be repairable, but I'd buff it out before thinking about doing anything else.
 
David703 said:
the smaller greenish ring looks to be the same color as the green primer at bottom of the chip. The other ring could be where the clear and base coat meet..



My vote is that u wet sanded into the primer. Did u buff it yet?



Why did u wet sand such a large area? If I filled that chip I would only try to wet sand the chip.
Click to expand...



+1



Looks like you sanded entirely too much.
 
This is not some old car... it a model 2007 year vehicle. I don't have a paint thickness measuring device.



OK so I buffed the thing out using SFX-1 and SFX-2... I got out a bright flashlight and it does appear that the OEM paint is too thin in that area and under bright light what appears to be primer is showing through.



I wrapped the sandpaper around a rubber eraser as described in the Paint Clinic article and honestly I was not too worried about sanding a larger area. Look at the pics shown, he sands quite a large area! I was not overly careful with the pressure either because it was such fine grit sandpaper and the article said nothing about oversanding, so I thought you'd have to be sitting there sanding it vigorously for an hour before 2000 grit would cut though the factory paint.



Any expects want to comment on whether I should re-touch this up? Or have I screwed it up enough that it should be repainted at a body shop?
 
DownFlyer said:
This is not some old car... it a model 2007 year vehicle.
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Lol, my bad man. What model car did you get with a purple tint? Last car I remember in a color similar was the old arse Monte Carlo's, I think...
 
DownFlyer said:
Any expects want to comment on whether I should re-touch this up? Or have I screwed it up enough that it should be repainted at a body shop?
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Anyone?



I would also consider solicitations from detailing people in the Toronto area who can fix this properly.
 
Just by looking at the pictures I'd say it's a typical problem with a blend job. The inner ring is just the new paint not really matching the old paint. There is a definate art to blending and I have much respect for those doing spot repairs after attempting this myself. I imagine the key to good blending is surface prep and getting the paint as close as possible to the original.



Anyways I had this exact same "ring" problem when I tried to airbrush a 4-5" section of a panel blind attempting my first blend job. I resolved it the other day on accident while I was prepping the panel to be fully repainted. I was sanding it with dry 1200 grit and all of a sudden the outer ring blend lines just dissapeared. The inner ring might always be there depending on what type of paint it is and how well it blends. My paint has blue flake in it and the touch up paint had less flake so the spot would jump out at you under the halogens.



Just read your most recent reply: Be careful when using the eraser and even 2000 grit. When using the eraser you are focusing on such a small area it's easy to sand too far. Having sanded my car (multiple times) the only time I've jacked it up is when I've used a small eraser. They can be very handy but they can also be very direct and destroy your paint job. Using a larger block would distribute the pressure more evenly over the surface so you're not sanding as hard.



There's nothing wrong with sanding a larger area just to fix a small chip. You can still focus on a specific area without putting so much pressure on it that you are sanding too hard. Most here will tell you to proceed with caution whenever you wet sand but it's been proven that compounding and even polishing can have a larger affect on your paint thickness. You can be extra cautious wetsanding without being a total pansy about it.



Since you can see primer though the paint it's safe to say you've went too far so why not attempt to patch the bigger area now? It's jacked up anyways so what's it going to hurt? Get that 1500 out and start sanding (with a larger block using even pressure) to see if you can remove some of those rings by going deeper.



Just a hobbiest suggestion here so proceed at your own risk...Also Pro's feel free to step in and correct my ramble.
 
DownFlyer, you went through the clearcoat, the color coat and dug into the primer. So, the panel is toast. The primer itself is a hard layer, so it will be as smooth as the attacking sandpaper. The problem is with wetsanding is pressure and finger marks. When you are inexperienced, try to act like a hovercraft; just barely touching the paint. After a few strokes, stop, wet the surface even more, wipe it down and inspect. The sanding marks should show a pattern, as you're starting to abrade the peaks of the factory orange peel away. So the paint is gonna be half shiny (in the valleys of the orange peel) and half matte (peaks). It looks marbled. Continue carefully, and when you reached the point where the sanded surface is totally uniform and matte, stop. Bring back the shine and done.



Finger marks are typical marks in the paint when you wetsand with your hand as the backing. The paper works under your fingers correctly, but between them the pressure is smaller, and this results in an ugly, wavy surface. Sometimes your fingers miss the target, aka the filled chip, and you sand down more on the side of the chip instead of hitting it directly. So, when you want good results, always use a nice, flexible backing, because it can follow the contours of the area. A rigid sanding block is only good for flat surfaces, and produces an attack point like yours.
 
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