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Researchers Cry Fowl on Car Paint

Thursday, May 5, 2011

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The next time you’re cursing a bird whose excretory calling card just ate into your car finish, you might want to blame the paint, not the poop.

Contrary to popular belief, bird dropping “acidity” is not the culprit in corroding your baby’s shiny finish. Look instead to the lacquer.

So say researchers at Autoglym, the UK car care supplier, who just completed a study on the toll taken on car paint by bird droppings.

Cool Car, Hot Car

The damage “results from the paint lacquer contracting upon cooling and molding to the uneven texture of the hardened deposit,” the company reports.

Blame the sun, whose summer rays soften and expand the paint lacquer, while drying and hardening the bird droppings by day, Autoglym says.

At night, however (or whenever the lacquer cools), the lacquer “contracts, hardens and molds around the texture of the bird dropping,” the researchers explain.

That fine-feathered finish may have a surprising cause.

The naked eye then perceives this molding as dulled or etched paintwork. That’s because the undamaged paint surrounding the dropping gives a clearer reflection in the light. The soiled, uneven area, on the other hand, interrupts the light’s reflection.

Acid Test

Researchers tested the theory with “strongly acidic, neutral and strongly alkali bird dropping substitutes”—no word on what they were—and found only negligible differences in the damage each caused.

They did, however, report a difference in damage based on grain-to-liquid content. The grainer the pseudo-poop, the greater the light distortion and the appearance of dullness when the paint molded around the mess, researchers reported.

They also found that the longer the “deposit” remains on the car, and the higher the temperatures, the harder the mess will be and the more damage it will cause as the car cools.

Somewhat surprisingly, Autoglym found that car waxes and polishes are of little help in protecting the finish, although they will make the droppings easier to remove.

Instead, the supplier says, quick action and a moist cloth are your best bets.

“It’s a great shame when an otherwise fabulous-looking car is blighted with a tell-tale patch of dull paint,” says Paul Caller, CEO of Autoglym. “As a result of this new research by our R&D team in Letchworth, we now understand why bird droppings are a frighteningly potent hazard to bodywork.”

There is no word yet on whether the findings might inspire a new anti-fowling coating.

Comment from Fred Marschall, (5/6/2011, 11:21 AM)

Don't blame the bird. He was just putting down a deposit.