Polishing the paint means to smooth the surface of the paint by polishing away material. Polished paint will appear clearer and more vibrant. Reflections will appear sharper and "spiderwebs" will be reduced. Waxing hides imperfections in the paint by covering them over to create a smooth surface, polishing removes them and lets the wax do a better job to let the paint pop. This can also repair stains that have etched into the paint like bird poop or vandalism. Polishing does remove a very, very thin layer of clearcoat or paint, so how often you polish is ultimately up to your preferences. I suggest once or twice a year. For polishing plastic or headlights to clear up cloudy lenses, see 1000q: polish headlights.
If your just purchased a used car and want to do a full detail, first clay bar the car to remove contaminants stuck in the paint.
Here's a quick test to see if your car could benefit from polishing. Take a bright light and look around the reflection. The reflection of the sun also works. Do you see lots of circular "spiderwebs" or swirled scratches? These can be polished out. If you can feel the scratches you need stronger treatment or a series of polishes over time to reduce them.
Where do spider webs come from? Harsh cleaning materials or towels, improper cleaning, or normal wear and tear create tiny scratches. I have never seen a used car that couldn't benefit from polishing unless that car was just polished!
Using a polish on the paint should be the extent of removing material from the paint under normal conditions Only if there is a noticeable scratch or severe dulling should you try using a light rubbing compound such as 3m finesse it over a larger area such as a panel. I have also tried Meguiars Step 1 scratch remover and find it to be similar to the 3m finesse it rubbing compound in strength. Turtle Wax's premium rubbing compound, (NOT the red colored paste in a can, that is way too strong, it's in a green plastic tube and is light green in color) is a little stronger than the 3m and Meguiars product and would be good for a first polish if your paint has some scratches and imperfections. If you have a scratch, isolate the use of rubbing compound to the affected area only. Polish is often called swirl mark remover but each brand and even combinations with different pads will produce different results. Even some paints tend to be softer than others. The turtle wax regular polish in a can is not very good for machine use because it is formulated for hand use and is only slightly lighter than their premium rubbing compound. It's decent for spot use on scratches. You should never put a hard rubbing compound such as turtle wax regular rubbing compound (the red stuff in a can) to an entire panel since it is best for spot use by hand only! Here is a list summarizing my guesses of strength, starting from lightest to harshest, please note that this changes according to what pad you are using and is my subjective guess. There are also many other brands that I have not tested, this list is my opinion only.
3m finesse it polish
turtle wax premium polishing compound (in a tube)
Meguiars Step 2 polish
Meguiars Step 1 paint cleaner - swirl mark remover
3m finesse it rubbing compound
Turtle wax premium rubbing compound (in a tube, is light green in color)
Turtle wax regular polishing compound (in a can, is white in color)
Turtle wax regular rubbing compound (in a can, is red in color)
I suggest a very light machine oriented rubbing compound for the first ever detailing if your paint has some imperfections. The turtle wax premium rubbing compound or 3m rubbing compound works well for a more dull finish the first ever application. Remember, t he premium turtle compound is in a tube, the regular is in a can, is red in color, and is way to harsh. After that, use light rubbing compound on spot scratches and then a full car light polish once or twice a year. Heavier rubbing compound is not appropriate and the more material you remove, the less you have to work with later. To put it into perspective, the entire thickness of the paint may only about 5/1000 of an inch think. It is better to polish less over a series of applications rather than more aggressively in one application.
If you use too hard foam or too hard compound, you will end up with holograms. These are spider marks that appear in one direction. You can't see them in dark light but in direct sunlight from the right angle or under certain lighting, it looks like streaking on top of the paint. If you get these, follow up with a softer polish and foam pad. To avoid these, do not polish until the compound is dry, it should always stay moist. More on technique below.
If you want good results, I would also recommend using a porter cable random orbit polisher and a spot treatment polisher. It's also sold under the Meguiar's name and as the ultimate detailing machine.
The advantage of a porter cable polisher is that it is suitable for use by beginners and advanced users. It makes it very unlikely to damage the paint unless you are being extremely aggressive and misusing the tool. Unless you are polishing only a small spot, I do not recommend polishing by hand unless you don't mind tennis elbow. Polishing an entire car by hand would take all day, which is not my idea of fun if there is a faster and easier way.
Note that the porter cable random orbit polisher is probably the best tool out there for home use. It's reasonably priced, works very well, and is compact enough to get into tight spaces. Unlike the cheapo 10" large random orbit polisher you can find at discount stores, the porter cable has a large, dual axis orbit and a free floating head. The 10" orbital polishers do not have a very good motion and you will find that they are not very effective at anything other than removing wax. The porter cable is also not a rotary buffer. Rotary buffers rotate on a single axis and are much more likely to damage your paint due to uneven polishing. The reason power drill or a sander attachments don't work well is because they're too fast. The ideal rpm is around 1000-5000 rpm and going too fast will dry out the compounds and cause uneven results.
A good spot treatment polisher is the mother's powerball for paint. If you only have a powerball mini, that will work for spot treatment. It is a foam ball that you attach it to a drill. It's the right size for polishing out the scratches under the door handles and for the lights. The powerball for paint is a softer foam and is the correct tool for paint, the powerball mini is a hard foam and you should use it with softer polishes to avoid holograms.
Below is a porter cable polisher. I didn't put the microfiber towel on the ground - you don't want it to pick up dirt! Also below are some of the compounds that I like to use. If you skipped the section above, the turtle wax can products are for spot use by hand only because they tend to be too rough for machine use.
Below: a porter cable random orbital polisher, 1 wash bucket, 1 chenille sponge, 2
polishing pads, and 1 microfiber cloth. I also suggest a few more cloths
and 1 rinse bucket.
First wash and dry the car. As simple as it seems, there are tricks to properly washing your car. See 1000q: wash and wax your car for more details. If the car is dirty, you will only rub contaminants into the paint and damage your polisher pads and paint. Tape over rubber trim or anything else you don't want stained white. Black rubberized trim or the black trim around the sunroof tends to become stained white if you don't tape over them.
Working on a section at a time, apply
polishing compound to the polishing pad and spread it over the dry (or nearly
dry) car to
splatter once you turn the polisher on. You want to use enough compound to
cover that section with a light coat, not enough to be flinged around when you turn on the buffer.
Remember that the car should be freshly washed and dry, a few water drops are
fine. If there is a lot of water, be
prepared to have a lot of polish get flinged around and to waste a lot of
product. Always use more polish rather than less. Not enough polish causes the
applied polish to dry out and causes excess wear on the pad. Once the
polish dries out, it is no longer effective and can cause holograms. Over time,
you will learn how much polish is appropriate. The amount of polish
pictured below was enough for the both doors and a little bit on the roof.
If you have some scratches, use a powerball mini or powerball for paint for spot treatment before doing the whole car.
If you just washed the car, the ground will also be wet. The extension cord that you are using is on the ground and covered with dirt particles. Make sure to avoid letting that dirty cord touch the paint, or else you will cause lots of scratches when you try to polish the paint! The dirt may also get caught on the polishing pad and cause more scratches. I suggest putting the cord over your shoulder. Your clothes will get some splatter on them, so wear work clothes that you won't mind getting dirty.
I suggest moving in a back and forth overlapping pattern which will cover the entire section evenly. You did smear the compound around, right? Otherwise it will get wasted when it gets flinged all over you and onto the ground. Try left-right, then diagonally one way, then the next. There is no need to press down on the polisher as only very light pressure is needed to let the pad do its job. If the pad stops rotating, you are either pressing too hard or need to add more speed. The speed adjustment goes from 1 to 6. I find that 5 is the maximum that you really need to use. 6 will cause excess vibrations, make it harder to control the tool, and build excessive heat. If you find that the compound is drying out too fast, add more compound if the problem is insufficient compound or spritz a few drops of water on the paint to keep it wet. The picture below is the initial application, polish until the compound starts to dry to a haze. You don't want it to dry to the point where it is flaking off.
When turning the polisher on or off, I suggest holding it gently on the
surface of the paint. This
prevents an over speed of the pad. It's less stressful on the bearings and
helps prevent compound that's already on the pad from getting flinged
off from no resistance and high speed.
For the corners or under the door handle, use the powerball mini and follow up with a polish. The powerball mini is a hard foam and is best for spot use.
Be careful not to pause on ridges or corners as this will cause more material to be removed from those spots. Many cars have ridges or raised areas on the hood. Because they are raised, the polishing pad will apply more action to these areas and remove material much faster than from flat areas. If you plan on having your car looking its best, it will need occasional polishing. It won't go through the paint as long as you are very mild, but remember that the ridges and high spots will prevent the low spots from getting polished. More aggressive pads and compounds can go through the paint if there's a very sharp crease or raised area and you sit on it for a while. The newest BMW and other cars have sharp creases in the sheetmetal, so avoid polishing the raised folds at all.
Once you're done, wipe off the polish with a microfiber towel and wax the car the scratch - free way, as seen in the article: 1000 answered questions: washing and waxing your car.
Final polishing note
Don't try to take a scratched up car and try to make it 100% perfect the first time polishing. If there are light scratches, you may just have to be happy making it less noticeable for now. When it's time to polish the car again, you can give those scratches some spot treatment and polish the car again. Do less now otherwise there won't be anything left to polish away later! If it's not noticeable from a few feet away, I would leave it alone for now.
After you have used the pad, put it into a bucket of clean, soapy water. Let it soak for a while, then wash and rise clean. Let it dry completely before you use it again. Don't try to machine wash the pads or else they can be damaged! With proper care, the pads will last a long time, so get good pads and take care of them.
If you have serious scratches or marring of the paint, you have to determine if rubbing compound is more appropriate. For most people, a light rubbing compound designed for machine use would be appropriate for a first polish. Never use harsh rubbing compound because it is not designed for machine use and will probably dull your paint!
If you still have questions on whether or not your brand of rubbing compound is appropriate, the answer is NO! It's always best to be conservative when removing material. Using more polishing compound for a longer period of time is a better than using less rubbing compound for a shorter period of time. Rubbing compound could be slightly or much more aggressive than polishing compound depending on the brand or formula and will remove material more quickly. And since you follow rubbing compound with polishing compound, it's another reason to be conservative. If in doubt, always start with the least aggressive compound first, then determine if more polishing or rubbing is needed. I would suggest using a Meguiars step 1 or Turtle Wax premium rubbing compound with the powerball mini for spot treatment.
First, determine the severity of the scratch and see if rubbing compound is appropriate. If you drag a fingernail over the scratch and you don't feel the edges, take a step back and try to polish out the scratch first . If you drag a fingernail over the scratch and your fingernail gets caught by the scratch, the appearance of the scratch can reduced by rubbing compound but not eliminated. If you see that the scratch goes through the paint into the primer or metal, you must have the scratch repainted or touched up. Remember that your goal may not be to erase the scratch completely as it may not be possible, first try to reduce the appearance of the scratch, then decide from there if it's worth it to remove more material.
If you determine that the scratch can be reduced with rubbing compound but doesn't need touch up paint, wash and dry your car first. Because rubbing compound is more appropriate for spot application, I recommend using a clean towel to apply the rubbing compound and to rub the area. If there is an improvement in the scratch, try rubbing the scratch some more and seeing if there is more improvement. If there is no more improvement, you have already rubbed off all the edges and should now clean and polish the area.
The best way to treat small scratches is with a powerball mini and light rubbing compound designed for machine use. This will fix or reduce the appearance of 95% of scratches. It might not end up perfect but it'll be close enough and not noticeable. This is the easiest and most cost effective solution.
If you determine that the scratch is too deep to be rubbed out, you can try touching up the scratch with paint. Personally, I would rather live with a not noticeable scratch than a large area with a botched touch up job, so be conservative whenever possible. First, sand the scratch with light grit sandpaper, 1500-2000 grit should be enough. You do not want to sand the area around the scratch, so I suggest taping off the paint around the scratch. Wipe the area clean with rubbing alcohol to clean the scratch of dust. Then, using a pin, apply touch up paint to the center of the scratch. Never use the paintbrush that comes in the bottle because it will leave a big blob. The paint will move into the scratch through capillary action and fill it in. Overfill the scratch slightly. Once it dries for at least 24 hours, sand the scratch flat and polish or use rubbing compound as necessary. This is a similar technique as in 1000q: paint chip repair. The difference is that a scratch is narrow and can polished out most of the time. A chip is too wide and large and cannot. Black, silver, and metallic seem to be the most difficult colors to touch up, so if you want a perfect repair, I would suggest taking it to a body shop and seeing what their opinion is. Normally, their opinion is to do the most expensive repair that is worth their time.
Here are some before and after pictures with flash and without flash. They are all from the same angle and with and without flash so that you can see that this is not a camera trick. I took the pictures under a fluorescent light because fluorescent lights let you see all the scratches. These scratches are from improper car washing and an automated car wash that uses brushes instead of a "no touch" car wash. It received a clay bar treatment and then polish. This didn't produce satisfactory results so it received light rubbing compound for machine polishers, then polishing again. It wasn't perfect but it was a huge improvement.