NOTE: This guide is only for scratches that have NOT gone all the way down to the bare metal/plastic (seems to be the most common, at least that's all I've ever gotten!). If the scratch you have actually has depth to it (able to catch fingernail in it when sliding finger over), and has NOT reached bare metal/plastic, this guide is perfect for you.
PURPOSE: I had never attempted to repair a scratch on a car before. I read as many things as possible via google searches and auto detailing websites/forums. While this gave me a good idea of the general theory, there was a LOT of different/conflicting information from source to source. The only way to cut through these varying methods was to just jump in and do it! I wish to save other people the frustration and confusion I went through because even with all that I read and studied - it was really only the trial and error that got me to where I wanted to go. Hopefully with this guide, you will have MUCH less trial and error to go through to repair that pesky scratch you've been eyeing.
SUPPLIES: Wax & Grease Remover, Touch Up Paint, Fine Tip Artist Brush, Multi-grit Sandpaper Pack, Rubbing Compound
-Wax & Grease Remover: They have these in various forms. Some come in a bottle like a pasty goo. For my purposes, I went with a spray can form. This is VERY important! The wax you may have on your car will not allow for the best adhesion for the touch up paint. You want the best adhesion you can get! Even if you do NOT wax your car, get this anyways. There can be other contaminants in the scratch area other than wax that will interfere with adhesion.
-Touch Up Paint: Cars will have a code for the paint used. To find this code on a 2014 Mirage, open up the front, passenger side door and it will be located on a mini-white sticker in the door jam. There will be a section labeled 'Body (clr)' and for my Infrared color, the code turns out to be 'P19' - If you have a place by you that will mix automotive paint, provide them with this code and they'll be able to mix a batch up for you. For me, I went the online route and got a small 1oz bottle of touch up paint from Paintscratch.com - there are various other online sources that will match car paint codes, so choose whichever you like.
-Fine tip artist brush: The brush provided as part of the bottle lid for touch up paints are UTTERLY useless! They are WAY too thick for scratches. Could be good for stone chips though.. Go to a hobby shop, or look online. Get yourself a fine tip artist brush, otherwise, you'll be applying paint unnecessarily all over the place. I found great success with a 0000 liner brush (yes, that's a quadruple zero size, meaning very fine. They also have 0, 00, 000, go either for 000 or 0000). I've read a lot of good things about using toothpicks..I dunno - I tried it - didn't work! I put the paint on the toothpick, put the toothpick to the scratch and the paint would not go on at all, it just stayed on the toothpick! Artist brush will work guaranteed.
-Multi-grit Sandpaper Pack: Sandpaper comes in various grits (roughness). The higher the #, the more fine it is. The lower the #, the rougher it is. This is where I ran into a lot of varying recommendations. Some said to start at 1000 grit, then move on 1500, 2000 until you finally get to 3000. The basic gist was that you start with a courser grit and move gradually to finer grits to blend the paint. I found this to be unnecessary. I just used 2500 grit exclusively and it worked out well! 3M makes sandpaper packs where there will be sheets of various grits, so this may be what you want to get if you want to experiment with different grits.
-Rubbing compound: After sanding, you will need a way to deal with the scratches left behind (as fine as they may be). For my application, I used Meguiar's Ultimate Compound. I LOVE this stuff!
Above pic shows the scratch I wanted to touch up. Someone who will remain nameless left this unfortunate accident on my gas lid door. It's quite noticeable..I had to do something about it. As you can see, the scratch is white, signifying that it has only breached the base coat layer of the paint without going all the way down to the metal of the gas lid door. If it had gone down to bare metal, I would have needed to use primer before applying touch up paint, but in my case it is 'only' a moderate scratch so I only need to apply touch up paint. Make sure you apply out of direct sunlight! Ambient temperature should be where you are comfortable in a short sleeve shirt and shorts. Extreme cold/hot will make for bad paint application experiences.
Above pic shows the scratch with the paint applied and dried. So, before you apply the touch up paint. I would wash the area first (car wash soap). Once the scratch and surrounding area is clean, follow the instructions on the wax and grease remover you bought to really decontaminate the scratch. Once that is done, use that fine tip artist brush to apply the touch up paint. Many sources recommend multiple applications of very thin coats..however when I tried to do this, I found that I would have an IMMENSELY hard time getting the paint to transfer over from the brush to the scratch. The paint would just stay on the brush (even worse using the toothpick method!), not getting in the scratch! I actually had to purposely take a little 'too much' on the brush to make sure it would actually transfer over. Your experience may vary with how thin the touch up paint you purchase actually is. My experience comes straight from using the paint from the touch up bottle from Paintscratch.com - no additional thinners/reducers added.
Since for my case, I had to go about with a thicker application - I actually don't think multiple coats are necessary, however I did anyways just to be safe. The stuff was dry to the touch real quick! I just let it dry for 5 minutes and applied a second coat. Some sources were saying to let it dry for 15..that would've been serious overkill for this. After the second 'thick' coat, that's it, I was done!
NOTE: If you should make any mistakes and want to erase it, have some isopropyl alcohol ready (I used 70%). A cotton pad with IA will wipe the touch up paint clean off even if it has sat there for several hours (trust me, I did it). The IA will also serve to clean up your paint brush after you're done (water won't do squat/or very little).
ADDITIONAL NOTE: No, you do not need the clear coat. I bought it just in case, but I don't see how I could have applied it. With even the first application of base color I did, that left no room for a layer of clearcoat since I was already over the surrounding paint level at that point.
So now that you have the paint applied, VERY IMPORTANT!! - let it dry for at least a week! The next step is to wet sand the touch up paint down so it becomes level with the surrounding paint. You want the touch up paint to be as dry and hard as possible before you do this. I read how some people have wet sanded only after letting the paint dry for a few hours and it turned out fine for them..so my first try, I thought just letting it dry for 24 hours would be more than enough. Nooope! When I wetsanded another scratch I was fixing to practice on, waiting only 24 hours, most, if not all the paint came off :-( - If you wait a week, this will not happen.
Above pic shows the result after wetsanding the touch up paint down. So, after you apply the touch up paint, you will notice not only is it higher than the surrounding paint, but it is also rough and not smooth due to needing mutiple strokes with the brush. This is why we sand it down. I had never heard of sanding something down wet before, but apparently the water is to ensure smoother, more even sanding. My method to wet sand was to simply have the garden hose continuously letting a small stream of water down while I was going at it with the 2500 grit sandpaper.
For the sandpaper, I just cut out a small rectangular piece, about 2.5 inches long, with the width of my index finger. Many sources warned against using just your fingers, and that a sanding block of some sort was necessary. For large areas, I can see this being a necessity, however for a relatively small area, I found success just using my index finger. The key for me was to use the stream of water coming from the hose as the thing that would ensure even sanding since I would let the stream go under the sandpaper, and use the water's surface tension to let my finger know how deep/hard I was sanding down
VERY IMPORTANT: Do NOT use a lot of elbow grease, do not push down. This is a case of letting the tool, in this case the sandpaper, do most of the work. Just go over it with light pressure, using back and forth strokes and you'll be fine. Some sources recommend using circular motions or even cross-hatching (start with horizontal strokes, then switching to vertical). I dunno..I did not employ these techniques. They could very well work, I can only speak on what I used. I followed the direction of the scratch (horizontal in this case) back and forth.
Also, be sure to check your progress OFTEN. I would do 6 light strokes, and then stop and check, visually inspecting and rubbing with my bare finger to check how much of a bump was left to guage how much I had taken off. It will not take long, even with something as fine as 2500 grit. I was not sanding all day. I finished the actual sanding process in only 3 or 4 minutes, 5 maximum.
Once you feel with the rubbing of the finger that you have got it level, stop and take a microfiber towel to dry the area. Prepare youself for a sinking feeling in the stomach because that exact feeling of horror is EXACTLY what I felt the first time I saw it. I was like..'what have I done to my car??!!' As can be seen in the above pic, THAT looks scary doesn't it?? Don't worry, that is why we have the rubbing compound!
Apply the rubbing compound to the scratched up areas until all you are left with is a shiny, smooth surface! Voila, you are done! I don't have a mechanical buffer, I did everything by hand. It only took me 3 applications of going over with Meguiar's Ult Compound to get the 2500 grit marks completely gone. It was insanely easy, just follow the instructions on the back of the bottle. When I first tried on another scratch I initially was using for practice before the main event, I had used 1500 grit exclusively...this..can work too actually. Just be very careful during the sanding process b/c you're going to be done real fast and it takes quite a few more applications of Ult Compound to completely get rid of the 1500 grit mark left behind. I think it took me like 6 or 7 passes with Ult Compound.
FYI - I did not feel the need to follow up the Ult Compound with a polishing product. Ult compound really does deliver good cutting power while somehow leaving behind a nice, glossy, shiny finish too! That's not supposed to happen!
Above pic shows the result of 3 passes with Ult Compound by hand. Before, I was absolutely mortified of even the idea of bringing sandpaper to my car's paint job. Now, I am very comfortable doing it! I am SO content with the result I was able to achieve. I did not think I would be able to get even half the result of what I eventually achieved since I've never been into detailing cars and such.
Above pic is a close up of the finished area. I included this to show that at very close range, you can still see where the touch up job is if you know where to look. Apparently, no touch up job can be 100% which is why professional shops will apparently recommend to just re-paint the whole panel even if it's just one little scratch. For my purposes, this is something I can definitely live with and is an exponential improvement over just leaving the scratch as it was.