Polishing vs Compounding: The Differences Explained


If you’re looking to correct swirl marks and scratches on your car’s paintwork, then you’ll need to understand the difference between polishing and compounding. These process are both designed to correct the paint, but work differently and should be used in different situations.

In this article, I’ll be going through the difference between polishes and compound liquids, to help you decide which you should be using. So let’s get started.

The Quick Answer

Polishing and compounding are both methods of correcting a car’s paint by removing a layer of clear coat. Compounding removes scratches from the paint more quickly whilst, polishing refines the finish by cutting the paint slowly. Compounding is often followed by polishing to correct the paint fully.

Paint Correction 101

Before we really jump into the specific differences between polishing and compounding, we need to get clear about what paint correction actually is.

Paint correction aims to flatten the clear coat so that it reflects light more evenly, causing it to look glossier. It’s that simple.

A car’s clear coat is very rarely perfectly flat, even on a brand new car. Often improper wash technique is the main culprit for scratches and swirl marks which cause unevenness in the paint, making it look duller.

To solve this issue, the damaged layer of clear coat must be “cut away”, to reveal a fresh, flat layer giving the paint a glossier and shinier appearance.

Polishing and compounding are two methods of removing the clear coat and correcting the paint. Both have the intention of removing the damaged layer, but they should be used in different circumstances because they work differently.

Compounding vs Polishing

The most important distinction between a compound and a polish, is how quickly they cut the clear coat away.

Polishing cuts the clear coat slowly, compounding cuts the clear coat quickly.

Compounding and polishing are two different actions. If you were to correct the paintwork, you would either be “compounding” or “polishing”.

Compounds and polishes are different products. This is an important distinction to make. If you purchase a “compound” you can expect it cut the paint away quickly. Whereas if you purchase a “polish” you should expect it to cut the paint more slowly.

This means compounds are more abrasive than polishes.

So why does the speed at which the paint is cut away actually matter?

Important Terms

Sometimes you can hear the terms “rubbing compound” and “polishing compound”, so where do these come into play.

A rubbing compound another term for a traditional “compound”, it cuts the paint quickly. A polishing compound is the same as a “polish” and cuts the paint more slowly.

From here on, I’ll just be using the terms “polish” and “compound” to keep things simple.

Which Should Be Used When?

So if polishing and compounding are both the same, in that they both remove a layer of the clear coat, why do they work differently.

Compounding is more aggressive, since it cuts the paint faster. This means it is more capable of removing more of the clear coat in a short space of time.

Polishing is less aggressive and a milder approach. It would take much longer to cut away the same amount of clear coat with a polish, than with a compound.

You’re probably still asking why this matters, and which you should actually choose. I think these two points are the most important to think about.

  • Compounding should be used to remove clear coat damage e.g. scratches.
  • Polishing should be used to refine the paintwork e.g. create a mirror finish.

This relates to fundamental difference between the two products, the rate at which they cut the paint away.

The Paint Correction Process

I think giving some scenarios and really explaining the process behind paint correction will help clear things up a bit more.

Say you have a car with loads of clear coat scratches that can be seen quite obviously in direct sunlight. This would be described as clear coat damage.

In this scenario, you could reach for a compound. This is because it would be a more efficient solution. Sure, you can cut away the same amount of paint with both a polish and a compound, however, it would take a lot longer with a polish.

On the other hand, say you had a car with very minor “swirl marks”, and you just wanted to give the paint a deeper level of gloss. In this case, you’d choose a polish instead.

A polish would be capable of refining the paintwork to really enhance the shine and gloss. A compound isn’t necessary in this situation because it unnecessarily removes too much clear coat and could remove some undamaged layers, as well as the minor damage.

Preserving the Clear Coat is Essential

This is the most important thing to consider whenever you’re performing any paint correction processes.

Always reserve the clear coat.

Why? Well, the clear coat sits on top of the base coat (the colour), and basically aims to protect it. It protects it from corrosion, UV rays and contaminants e.g. iron, tree sap, tar bugs etc.

Without the clear coat, the base coat would fade very quickly, and the finish would basically look matte and not glossy and shiny.

Every time you either polish or compound the paint, you remove some of this clear coat. Of course, there are only so many times you can do this before you run out of paint.

When this happens, you would basically have to respray the car.

But running out of clear coat entirely, isn’t the only problem you need to consider.

Like I mentioned earlier, the clear coat protects the base coat from UV rays which cause it to fade. The clear coat has “UV inhibitors” in the paint to do this.

However, these UV inhibitors are not distributed evenly throughout the paint. Instead, most of them sit at the top of the clear coat. So when you remove these top layers, you risk removing a lot of the UV protection the clear coat provides, even if there’s plenty of paint left still.

And that’s why you should only ever remove as much clear coat as you need to, to effectively remove the damage, and never any more than is necessary.

Sometimes, it is necessary to leave some of the damage left in the paintwork, in order to preserve the clear coat. Having flawless paint is far less important than having a functional clear coat.

Take a look at this article I’ve written on how often you can correct the paint to find out more about this topic.

Compounding Can Leave Hazing

I made the important distinction between polishes and compounds earlier, that polishes refine the paint, and compounds remove clear coat damage.

Since compounds cut the paint faster, they are more abrasive and hence, more aggressive. This means that they generally don’t leave a completely refined finish.

Instead, they can leave tiny “scratches” left behind.

Polishing is used to refine these scratches. Since it’s milder, it helps to smooth the paintwork out and leave a completely flat surface.

Think of it like sanding. You first use a heavy sanding paper to remove deep scratches. Then you use a lighter grade to remove the scratches left from the sandpaper you used before hand. It’s a similar process.

Hazing left by the compound
After polishing

Some compounds are capable of leaving a very flat surface behind. In this case, a polish isn’t always necessary because the paintwork is already refined.

It really depends on what products you’re using. Generally, the more abrasive, the higher the tendency to leave hazing behind will be.

To the untrained eye, this hazing probably won’t even by noticeable. It often takes careful inspection under very bright light to detect it.

One Step Products

There are also one-stage or one-step polishes/ compounds. These are designed to have the best of both worlds.

The aim, is to remove clear coat scratches and swirl marks but still leave a mirror finish behind, without any of the hazing that a compound would likely instil.

These products aren’t actually too good to be true, and can be very effective solutions. However, they do come with some drawbacks.

  • They don’t always effectively remove deeper clear coat scratches.
  • They won’t always leave a perfectly refined finish.

It’s really a trade-off.

Often, you’ll get better overall results using a two-stage paint correction technique (compounding followed by polishing). However, it takes twice as long.

If you pick a good all-in-one product, the results can be almost as good, but in half the time.

If you’re pushed for time, and aren’t “chasing perfection”, then they can be a great option to go for.

Back to an Example

Let’s go back to the earlier example. A car like the one below, has quite a bit of clear coat damage (scratches and swirls).

So you could look at this and jump straight to a compound, because the damage is quite severe. Then you’d probably follow it with a polish to refine it to a mirror finish.

But remember what I said before about clear coat preservation?

It may well be possible to remove the damage using only a polish. It’s really difficult to tell, because there are so many variables involved.

If you’ve stuck this far through the post, then you’re clearly very interested in paint correction and want to get the best finish possible, whilst still making sure your car is protected (has plenty of clear coat left).

If that’s true, then definitely keep reading because I’m going to be talking about all the caveats to this topic of polishing vs compounding. And they’re really important if you ever plan on taking a machine polisher to your car’s paintwork.

You’ve probably realised by now that it’s not very clear cut, and there are loads of variables to consider. So let’s take a look at some of the most significant.

The Polish or Compound Liquid

Not all polishes and compounds are created equally. It’s possible to get a mild compound, and an aggressive polish. And this is where the line tends to blur a bit.

Some polishes are pretty capable of taking out swirl marks, whereas others will only refine the paintwork slightly to get that final 1% of gloss.

Equally, some compounds are very aggressive, whereas others may only cut the paint away as fast as an “aggressive polish” by another manafacturer.

Normally, brands that produce polishes and compounds tend to have a range. Instead of just having one of each product. Then the “one-step products” will lie somewhere in the middle of the spectrum.

How Soft is the Paint?

This is a big one. Some cars have “softer” paint than others. This means that the clear coat will be cut away more quickly.

Don’t be lulled into the naive thinking that all cars have the same “paint softness”, or that it won’t make a whole lot of difference”. In fact, this is as important as the polish or compound you are using.

It really varies between car manufacturers. Audi, Mercedes and BMW are all fairly well-known to product cars with “hard” paint.

Whereas, manafacturers like Toyota, Honda and Porsche produce cars with comparatively “softer paint”.

So it may well be that a polish would be capable of removing a certain amount of clear coat on a Porsche. But the same polish wouldn’t be able to remove the same amount of clear coat on an Audi.

However, be careful with this information. Just because you have a BMW, doesn’t mean that your car has “hard paint”, and that you should use a compound. Every car is different. It’s just another variable to consider.

Man vs Machine

You also need to consider either correcting the paint by hand, or using a machine.

A compound used by hand, can actually be a lot less aggressive than using a polish on a machine.

There are two main types of machine to consider as well.

If you don’t know the difference between rotary and dual action polishers already, then definitely check out this article I’ve written on dual action vs rotary polishing machines to really get to grips with the differences.

But in short, rotary polishers cut the paint faster than dual action (DA) machines. This throws another very important variable into the mix.

So understand that a compound will cut away far more paint when used with a rotary, than with a DA.

Rotary polishers are also far more prone to leaving hazing, because they cut more aggressively.

So you should never use a polish and a rotary together, with the aim of “refining” the paintwork to a mirror finish. Instead, rotaries should only be used to remove significant levels of clear coat damage.

Pad Type

The pad type is yet another variable to consider. There are two main types of pads: foam and microfiber.

Microfiber pads are typically more aggressive and cut the paint faster. So it may in some cases be possible to remove the same level of clear coat using a microfiber pad and a polish, as when using a foam pad and a compound.

However there are many different types of foam pads. Often, manufacturers have several different types, some designed for “compounding” and some designed for “polishing”.

Generally, the firmer the pad, the more aggressive it will be. So again it’s possible to cut the same amount of paint using a hard foam pad and a polish liquid, as when using a soft foam pad and a compound liquid.

Other Variables

So just in case you aren’t already confused enough, there are several other variables to think about. But don’t worry, I’m just going to bullet point them to stop stressing you out even more.

  • Speed of the machine (how fast the pad rotates). Faster rotations = cuts the paint faster.
  • Speed of your arm movement (how fast you cover a certain sized area).
  • How much pressure there is on the polishing machine (how hard you press down when using the polishing machine).

So Should You Polish or Compound?

So I really hope that I haven’t confused you too much, or put you off performing any paint correction techniques. I just wanted to highlight that it’s quite complex, and there’s much more that goes into the thought process, than just selecting a compound or polish.

I thought it’d be a good idea to really just round things off and simplify everything so you know where to go from here.

So here’s what I’d do if I was a beginner, trying to decide between using a compound or polish.

  • Select a dual action polisher, or try paint correction by hand if you’re not confident enough yet to use a machine. Don’t use a rotary polisher.
  • Choose two products from the same manufacturer (a polish liquid and a medium-grade compound liquid).
  • Try using a “polishing liquid” first on a foam pad.
  • If it doesn’t remove the damage, use a “compound liquid” on a foam pad.
  • If this still doesn’t remove the damage, use the same “compound liquid” on a microfiber pad.
  • Keep repeating the same section until the damage is removed.

This is the process I first used, and the one I still use today. Yes, it can take a bit of trial and error, but it’s the best way to get a great finish, but still preserve the clear coat.

If you’re interested in which products I use, then check out my recommended paint correction products page where I list my favourites.

You don’t need to over complicate things. Keep it simple and you’ll get great results.

Related Questions

Finally, I wanted to go through some of the most frequently asked questions to clear up any issues you may still have.

Should I always polish after compounding?

You do not always need to polish after compounding. It depends on the finish left behind by the compound. If there is any hazing or swirling, use a polish to refine the finish. If the compound has left a glossy and smooth finish, then there is no need to polish.

What’s the difference between buffing and polishing?

Buffing is used to apply products like waxes and sealants to protect the clear coat. Polishing is the process used to describe the removal of a layer of the cleat coat to remove scratches and imperfections. Buffing does not remove any clear coat.

What is wet sanding?

Wet sanding is another common paint correction technique. It’s a step more aggressive than compounding and should only be used by people who really know what they’re doing. Take a look at the article I’ve written on polishing vs compounding vs wet sanding to learn more.

Thanks for reading! I hope you’ve found this article helpful. Check out the rest of the website to learn loads more about car detailing techniques and tips.

Heather

I first became interested in car detailing around 3 years ago and learnt all the main techniques on my very first car. I spend a lot of time detailing my current car, and trying to keep my family's cars looking presentable too!

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