Media post: Polishing Out Defects From Your Car: How Deep Do You Go?

It’s every car owner’s nightmare. You come back to where you parked your car and there, in plain view right in the middle of a panel, is a great big scratch.

How it happened, whether it was someone walking past carelessly with a bag, or maybe a cyclist losing control momentarily, or a stone kicked up by a passing vehicle, you have no way of knowing.

But what you do know is that you’re going to have to get it fixed.

Your first thought is probably about the cost. Professional bodywork can be expensive. But a scratch is not like a big dent or having a completely mangled panel after an accident. Depending on the depth of the scratch, you’d be pleasantly surprised how easy it is to put right. It’s a job you can even do yourself.

Polishing out defects from a car requires some car polishing equipment – cutting polish or compound, polishing pads, finishing polish. You would also need some detergent and sponges to give your car a thorough wash before and after, and some wax or sealant to protect your newly polished paintwork afterwards.

In an ideal world, you’d also have a polishing machine or wheeler to make the job easier, although polishing can be done by hand. It just takes a little more elbow grease!

But what do you do once you have assembled all of this gear? Many people find the prospect of polishing their own car daunting, on the grounds that if you get it wrong, you can badly mess up the paintwork. While this is true, it’s actually harder to make a complete mess of a polishing job than you might think – as long as you follow some simple and straightforward rules.

Don’t jump in too deep!

The most important of these rules is this – if you use a polish that ‘cuts’ too deep into your paintwork, it can’t be undone. With a softer polish, on the other hand, even if it doesn’t remove the defect you are trying to get out, you can always move on to a harder polish.

The golden rule, then, is always start with finer cut polishes and move onto heavier if you need to. This also captures the secret to a successful polish – it’s all about cut, it’s all about how deep you go into the paintwork.

Let’s explain in a little more detail.

Car polish is abrasive. It ‘cuts’ into the paintwork of your vehicle using the friction created between the polishing pad, the polishing substance and the bodywork. Heat created by the friction of rubbing an abrasive material against the paint actually makes the top, clear layer of the paint softens and turn viscous. As you continue to rub, the softened upper layer gets pushed into scratches, marks and defects, smoothing them over.

Not all paintwork defects and marks are the same. Some are very shallow and only just affect the very upper part of the clear coat. Examples that fall into this category are so-called holograms and swirls – marring that is only visible when it catches the light just right, and which are most commonly caused (ironically) by poor polishing and washing techniques (including abrasive cloths and rollers in car wash machines).

Other marks are much deeper, and therefore more visible. Scratches will be prominent if they cut deep into the clear layer of the paint only, or they can also penetrate deeper all the way to the base or even primer coat.

Cut to the chase

How deep the defects go will determine how much ‘cut’ you need from your polish and pads to put them right. Very shallow defects can often be buffed out using relatively soft pads and only mildly abrasive polish. In fact, although the name ‘finishing polish’ suggests it’s what you use at the end of a polishing session, very light marks can be removed using products like quick detailer sprays.

For deeper scratches, you need more abrasive polishes. There are two broad categories of bodywork polish – cutting polish which is moderately abrasive, and then so-called cutting compound, which is more heavily abrasive and only to be used for tackling the worst paint defects. Both cutting polishes and compounds come in different grades, and so too do polishing pads, from soft / fine to heavy / highly abrasive.

For reasons already mentioned, you should take care not to jump into using too abrasive a polish straight away. Even if a scratch looks like a bad one, you can’t really tell for certain how deep it really is. Never, ever be tempted to jump straight into using a heavily abrasive cutting compound – you’ll be cutting deep into your paintwork and could easily do more harm than good.

Start with a light-to-moderate polish and take things from there. You might find it does the job and gets rid of the defects you were most worried about. If not, you can always move onto a coarser polish and try again.