Unless the previous owner of your car polished the paint to a perfect finish and kept it that way your car can use a good polishing. That statement holds true for a new car or a car with new paint since high production demands rarely leave room for perfection before handing your car off to you.
While finishing technology has come a long way, automotive paints are still susceptible to scratches from improper washing, etching from bugs and bird droppings, pitting from brake dust, and oxidation from the elements. All of these things have diminished the appearance of your car’s paint.
Fortunately for you polishing provides for a very economical way of restoring or improving the appearance of your paint.
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What Do Polishes Do?
At the most basic level, a polish is rubbed against surface of a material such as paint and removes microscopic layers of the paint to even out the surface. It’s this evening out of the surface that removes the appearance of scratches or dullness.
A Little about Automotive Paint and Scratches
Most modern automotive paints are made up of at least three layers, the primer which is the base layer, the color coat which is the mid layer, and the clear coat which is the top protective layer. The clear coat layer on your car is the layer you will be polishing away and is extremely thin, roughly half the thinness of a piece of line paper.
Scratches and etching that only penetrate a small fraction of the clear coat can usually be polished out. You can see this represented in the above picture by the dotted line which represents the layer of clearcoat after polishing. These will be most of the swirls and star bursts you see when the sun hits your paint straight on.
If the scratches are too deep you’ll have to remove too much clear coat to even out he surface and hide the scratch which will weaken that section of clear coat. At best you’ll improve the appearance of the scratch by rounding off the edges of the scratch while polishing and reducing it’s visibility. These scratches are sometimes referred to as RIDS or Random Isolated Deep Scratches.
If the scratch penetrates the clear coat layer into the color coat or primer you will not be able to fix the scratch or improve its appearance much with polishing.
In general, if you can feel the scratch with a fingernail, you’re not going to completely get rid of it without removing a lot of clearcoat and may not be able to get rid of it at all.
If you can swing it, I recommend buying a paint thickness gauge to know exactly how much clearcoat you have and how safe it will be to polish it down a lot.
How Does Polishing Work?
Polishes work by means of abrasives. Abrasives are tiny particles suspended in a liquid or paste that scratch away layer after layer of paint until you reach your ideal surface finish. This, of course, means you need to start polishing with a clean contaminant free surface.
The suspension liquid in polishes acts as both a transport for the abrasives and a lubricant to allow the abrasives to be rubbed against the paint for an extended period of time. It also suspends the paint that you remove while polishing so the abrasives can continue to work against the newly uncovered paint.
The abrasives in polishes can have varying levels of aggressiveness. This allows you to use an aggressive polish to remove paint faster (which can leave it’s own micro scratching or micromarring) and then follow it up with a less aggressive polish to remove the aggressive polish’s marks for a flawless finish.
Some polishes even have abrasives that break down as they are worked to finish out smoother (more on this later).
Types of Polishes – Compounds vs Polishes
Polishes are broken down into two main categories, Compounds and Polishes. Compounds are more aggressive and used for removing heavy scratching, oxidation, etching, etc… but don’t always finish down to a perfect finish because they can leave behind their own micro scratching. Polishes are less aggressive and are used to remove really light scratches or the micro marring left behind from Compounds.
Some polishes are even broken down further into cutting polishes and finishing polishes. This is just a fancy way of saying more aggressive and less aggressive polishes.
Types of Polishes – Diminishing vs Non-Diminishing
Remember when I said some polishes have abrasives that start out more aggressive and break down as you work them to be less aggressive and finish out smoother? This is what is referred to as a diminishing polish. These are sometimes referred to as DAT polishes or Diminishing Abrasive Technology polishes.
The upside is these polishes leave behind less micro marring so you don’t have to follow them up with a finer polish. The downside is they can diminish before you’ve polished away your defect so you have to start over with fresh polish.
On the opposite side of the spectrum there is non-diminishing polish. This is polish that has abrasives that don’t break down and are a fixed aggressiveness. You’ll sometimes see these referred to as SMAT polishes or Super Micro Abrasive Technology polishes.
The downside to these is you’ll have to follow up with a finer polish if it leaves behind any micro marring. The upside is you can work the polish into the paint as long as you need to without it breaking down so you get more consistency and control. When I’m working on scratches in clearcoat I prefer non-diminishing compounds and polish.
What Pads are the Best for Polishing?
There is a lot more to this topic, which I discuss more about in my article The Ultimate Beginners Guide to Buffing Pads, but I’ll give the abridged version.
Pads are made in a variety of different materials. You can buy them in wool, foam, and now microfiber. Fibrous pads like wool and microfiber are the most abrasive because the individual fibers are an abrasive and provide more surface area for polish abrasives to stick to. Fibrous pads tend to leave behind micro-marring unlike foam pads.
Wool is usually the most aggressive and doesn’t finish down as nice (leaves micro marring) as microfiber and foam . Microfiber is usually less aggressive than wool but more than foam. Foam pads tend to be the least aggressive.
Both microfiber and foam pads are available in compounding/cutting pads and polishing pads. The cutting pads are designed to allow for more aggressive compounding than the polishing pads.
I recommend microfiber cutting pads such as Meguiar’s Microfiber Cutting Pad for the initial compounding of severely neglected paint. I then follow up with a microfiber or foam polishing pad such as Griot’s Garage Black Polishing Pad to clean up the micro-marring from the microfiber cutting pad. Some paints are so soft that even the polishing microfiber pad will leave micro marring and will need to be finished with a foam pad.
If the paint is only moderately neglected I recommend starting with a foam cutting pad such as Griot’s Garage Orange Correcting Pad and following it up with a foam polishing pad.
There is no standard of color between pad manufacturers. You’ll have to rely on the manufacturer or retailers description of each pad to know which is a compounding/cutting pad and which is a polishing pad.
What is the Best Polish for Clear Coat?
While this can, and should, be a whole topic on its own I’m going to try and simplify this decision for you. The gist of polishing is that you want to use the least aggressive means of removing the scratches you want to remove. This is so you don’t waste precious clear coat and shorten the life of your paint. Some clear coats are softer than others so you really have to be careful with how aggressive of a polish you start with. Your best bet is to pick a middle of the road compound and polish from the same manufacturer and series for your first foray into polishing.
My favorite is the Ultimate Compound and Ultimate Polish from Meguiar’s. On most clear coats Ultimate Compound is just aggressive enough to be able to remove most defects and the Ultimate Polish finishes it out really nicely when combined with a quality foam pad. On harder clear coats you can still remove most defects by using it with a microfiber cutting pad. On lighter colors like metallic silvers and whites you’ll find Ultimate Compound finishes out well enough to just straight up skip the Ultimate Polish.
Both Ultimate Compound and Ultimate Polish are non-diminishing SMAT polishes so you just work them into the paint until you’ve reached your desired appearance. They are very user friendly in that they don’t dry out quickly so you can work them longer and don’t have to worry as much about heat and humidity. They are also very affordable and easy to find.
Should you need an aggressiveness beyond those two polishes, or you’re unable to find them for purchase, you’ll want to reference a chart such as this one to determine a more suitable polish.