How to Sand and Polish a Car so the Paint Looks Good as New
Do this at your own risk. This technique is not guaranteed to work with every car. However, it will work on 90% of vehicles made after 1990 or that have been repainted within the last 15 years. Before taking any action, read this guide thoroughly and make sure you understand every step. If you have any questions, I will be around to answer, so go ahead and ask.
This is what is done at most auto body shops after a car is painted to ensure top-quality finishes. However, the purpose of this guide is to help anyone with an old paint job to revitalize it without spending the $300-$500 or more that the average shop will charge for this job.
You Will Need:
- A lot of spare time. This might take you a couple of days to finish.
- Sandpaper, the wet sanding kind. The grades you will need are 2000 and 3000 (preferentially the foamy type) and possibly 1200 or 1500.
- A sanding squeegee
- A couple of micro-fiber cloths
- A bucket, water, and liquid soap
- Medium-grade rubbing compound and fine grade polish
- A hand-glaze product and an applier
- A buffer tool, a buffing foam pad (white, harder foam), and a finishing foam pad (black, softer foam)
You can get all this things at an auto parts store. You might be looking at spending about 150 dollars (if you buy a buffer), but you will have a tool that will last you many years and enough supplies to do three complete buff jobs or more.
Step One: Evaluate
There are many different ways to go about this, depending on the current state of your paint job and your goal. If your paint is very dull and has many small scratches, you might want to go all the way, starting from step two. If it's in pretty good shape but you want to give it that extra shine to make it look good as new, then you might want to skip steps two through four and get straight to buffing, although step four is always recommended for that deep and slick professional look. If it's somewhere in between then you may start on step three.
Step Two: Test and Wet Sand With 1200 or 1500 Sandpaper
This step is only recommended if your paint job is around 12 or more years old, has many small scratches, or looks like it was poorly painted. Before you go and sand the whole car, do a test on a small area; a lower corner in the rear bumper is a great place to do your test.
Should you use 1200 or 1500? It depends on how bad the paint is. Both are very similar sand grades, but while 1200 is faster, it might be harder to get rid the scratches it will make. It is up to you; I use 1500 most of the time in cases that need it. Moving on:
Fill a bucket with water and a small amount of soap, cut your sandpaper sheet in two halves, hold it horizontally and cut a vertical line right in the middle. Let one half sit in the water for about five minutes before you begin, then wrap your sandpaper around your sanding squeegee. If you cut your sandpaper correctly it will fold in three equal parts. Now start sanding your test area by laying your squeegee flat on the surface and sliding it left and right a few times then moving down and repeating the pattern. You can use your squeegee to dry a small area very quickly. Do this from time to time to check your progress. If you can sand to a perfectly flat finish without the color coming off (you will notice the water getting tinted if this occurs), you are good to go.
Do this to the entire car. Make sure not to overdo it, as you could ruin your paint. If you notice that there's color coming off, it's time to stop and move on (you should move on way before that happens). Avoid sanding in places where you won't be able to polish with the buffer, such as edges, around plastic or rubber trims, and around door handles. Rinse and and clean every part after you are done with it. We are ready to move on to step three.
Step Three and Four: Wet Sand With 2000 and 3000 fine grade
The purpose of step three is to make any scratches caused by the 1200 or 1500 sandpaper to disappear. If you skipped step two, you will need to do the test described in that step except with 2000 grit; if your paint is fairly new, you can go straight to step four.
You will spend about the same amount of time wet sanding with 2000 as you did with 1200 or 1500 grit, but you will need to be more careful and keep track of the parts you are done with. For an untrained eye, there won't be a noticeable difference between the two types of scratches, so just make sure you sand evenly and thoroughly, though, once again, be careful not to overdo it. The sanding pattern is the same as in step two. Don't forget to rinse and clean each part before and after you are done.
Step four is basically the same as step three, but you will be using a 3000 fine-grade sandpaper. This step can (in theory) be skipped if you have a rubbing compound that will buff out 2000 grit scratches, which works mostly on lighter color cars. However step four is highly recommended if you want the ultimate finish. Another plus is that you will spend less time buffing if you do it.
Step Five: Polish
Get ready, the best part is about to start. At this point, you might be sick of wet sanding, but you are about to find out why it was worth it. Start by making sure your buffing pad is perfectly clean and properly attached to your buffer. Make sure to avoid getting the cable in the way since it might cause a serious accident if it gets trapped by the spinning part of the buffer. One way to make sure you prevent this is to pass the cable over your shoulder, keeping the slack behind your back. This will also help you avoid scratching your paint with it.
Add rubbing compound and start buffing. Do this in sections of about a square foot at a time, for best results. Use an orderly motion: left to right, right to left and then down and repeat the pattern. Repeat this step until you are satisfied with the result, it usually takes about 2-3 passes to obtain an awesome shine. Never use too much speed or too much compound. Most buffers have a revolutions regulator, which you should set at mid speed. After you are satisfied with each part, do a final pass, lowering the revs a little.
After you are done buffing, switch to the black finishing pad. Do a slow pass with a finishing grade polish and make sure to dampen your pad a little now and then to avoid burning the paint.
Clean every part after you are done with it. Make sure you clean every edge very well before the polish hardens up; I recommend that you use a damp micro-fiber cloth. You can use an old toothbrush or clean paint brush to clean the places that are hard to get into, but be careful not to use too much pressure in order to avoid scratching.
Step Six: Hand Glaze
By this point your car should look awesomely shiny but it might show the pattern that you followed with the polish if you see it under direct light. That's the reason why you will need to do this step. I recommend that you use a silicon-based hand glaze product rather than a wax-based one, simply because it gives me better results and it seems to have a longer lasting effect. Either type you choose will give your paint a thin protection layer and a little extra shine. Make sure you do this in the shade; direct sunlight might cause the glaze to dry too quickly and stain your freshly buffed car.
Apply a small amount directly on the first part you will glaze (a few drops is enough), then use the applier with gentle pressure to rub and smear the product evenly on that section of the car, working square foot by square foot. When the applier feels too dry to continue, add a little bit more product, but only use a few drops each time. When you are done smearing the product, let it sit for a couple of minutes. Now use a clean and very slightly damp micro-fiber cloth to clean it off. Repeat the process with the other parts until you are done with the whole car.
Congratulations, you are done renewing your paint. If you want it to last in this condition for much longer, you should hand glaze your car once every couple of months.
It's time to take your car for a ride. Be ready to receive some compliments from your friends and to turn a few heads. Good job!