How to keep your car's paint looking good

Australia is a dangerous place, and even more dangerous in summer. A decent percentage of the native reptiles, fish, cnidaria, invertebrates and arachnids are out to kill us. And as summer approaches, so do a whole other series of perils for car owners – namely, all the flying and heat-related things that seem to get off on damaging our cars’ paintwork.

Here’s a list of warm-weather paint-job threats to keep an eye out for.

The very top layer of your car’s paint is clear – it’s called ‘clear coat’. It’s a protective layer that protects the paint underneath from scratches, sun damage and rust, and also gives it a sleek shine. But sunscreen loves to chomp down on clear coat like a snail with an appetite for fledgling garden veg.

If you’ve ever left a handprint on your car after a beach trip, you’ve probably wondered why it lingers. And just like stains on delicate fabrics, the longer you leave sunscreen marks before you clean them, the more stubborn they’ll become. The offending ingredients are common to most sunscreen formulas – polyethylene glycol and titanium dioxide – and while they amplify your skin’s natural sun protection and guard against UVA and UVB rays, they do the opposite for clear coat.

The precise scientific explanation for this unfortunate pharmaceutical witchcraft eludes us, but we can tell you that your best option is to clean sunscreen off your car posthaste. A proper cut-and-polish is the best removal method. If you leave the marks to bake in, your only option may be to have the damaged panels professionally restored – and that can be very expensive.

Salty air and humidity are metal’s natural enemies. While oxidisation can occur from the presence of water alone, salt rapidly accelerates its development. Salt is hygroscopic, meaning it absorbs water, and it also increases water’s conductivity, speeding up the transfer of electrons involved in the oxidisation (rusting) process. Occasional beachgoers don’t have too much to worry about when it comes to salty air and spray, because prolonged exposure is the thing that causes the most damage – so if you live by the beach, you ought to be more aware of salt’s desire to eat your paint-job.

Ocean-adjacent cars develop rust eventually – it’s going to happen to yours. All you can do is try to slow the process. Wash your car regularly and you shouldn’t have much to worry about. Since the intro of clear coat as standard in the ’80s, our paint jobs have an extra layer of protection from the elements, so it’s really just all the other metal components you need to keep an eye on. There’s not a lot you can do to stop corrosion under the hood besides getting your mechanic to give the engine a good clean when it’s serviced, but prevention is best. If you’re super precious or paranoid, keep your car in a garage or protected by a breathable car cover. Some coastal-dwelling auto enthusiasts even install garage dehumidifiers to further guard against salt attacks.

What’s so bad about a fruit bat’s scat? The diet of the humble, grey-headed, hendra-virus-riddled flying fox (the kind you find at Yarra Bend in Melbourne and all the way up the east coast) is largely nectar and pollen. Nectars and pollens have a pH of 2.7 to 6.4, depending on the plant, and while an acidic diet doesn’t always equal a corrosive expulsion, car detailers say it’s actually the uric acid in the urine accompanying number twos that does the damage. The bottom line: if bats defecate on your duco, clean it ASAP.

Additional warning: If your local bats like to eat fruit, prepare for hellfire rained down from above. If you’ve ever visited a cherry farm and eaten more fruit than you’ve left with, you’ll know what we mean.

If you return from a driving holiday with a bug-free bonnet, have you even been on a real road trip? We think not… at least not in Australia. During summer, the bug carnage from a single drive can be bloodier than a GoT season closer. As they decompose, splattered bug corpses emit acidic enzymes and eat away paintwork like miniature terrestrial Xenomorphs. If you find the idea of sporting a bonnet bra abhorrent, we can relate – so make sure to check your front for flying casualties after every outing. Gently wipe off any bug guts using a damp chamois or microfibre cloth so you don’t scratch the paint. And yes, there is such a thing as bug remover, so keep a can and a cleaning cloth in your garage.

Parking your car during summer is a catch-22. Unless searing your shoulder with a molten seatbelt buckle appeals to your masochistic side, for the love of god, park your car in a shady spot underneath a tree. It’ll keep your car cooler – but the trade-off is poo, especially if you park overnight. So how does the faeces of our feathered foes damage duco?

Authorities on matters of poop and paint (car detailers) tell us the small white centre of a bird’s poo is actually uric acid (birds don’t pee, so this is the next best thing), and it can have a pH level of anywhere from 3 to 4.5, depending on the bird’s diet. In hot weather, car paint and clear coat heat up and expand around the excrement, which also makes the clear coat more porous. The clear coat absorbs the uric acid, which begins to damage the paint underneath, and when the temp goes back down, the paint contracts back around the poo as it cools, leaving those awful etch marks in your duco. This is also why the grainier the poo, the more uneven a mark it’ll leave.

The moral of the story: never let the sun come up on a poo stain.

Those intense summer northerlies can whip up a lot of dust and deposit a perfectly even film onto your car. An accumulation of dirt and grime can be an irresistible invitation to a budding artist with a puerile sense of humour. Have you ever drawn a dumb doodle on a dirty car? Or, literally, a doodle of a doodle? If you haven’t, good. If you have, shame on you. Your drawing – no Mona Lisa, it must be said – could be immortalised in someone’s paint job for the remainder of its natural life.

How does this happen? Heat softens a car’s clear coat, and wiping your finger through dirt, dust and grime to create your artistic masterpiece grinds these tiny particles into the clear coat’s surface, making your prankster artwork as permanent as an ill-conceived tattoo acquired during a bucks party. And just like that jokey bro tatt, there’s no easy fix for this one either, folks. Just don’t do it.

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