Common Sense 101 - Engineering - December 16, 2012 Edition

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41. Paint Job
id you know that a good paint job on a car can cost upward of five grand?
I’m not joking. Yes, sure you can get a paint job done on your car for a few hundred bucks, but it’ll look
like crap when finished. You’ll see overspray (that’s paint where it shouldn’t be), peeling, dust under the
paint, and lines from the sanding process. And in time, a cheap paint job will fade much more quickly than a
good one.
Well, why should things need painting in the first place? Why not make everything out of materials that
don’t need painting (unless you want to change the colour)?
As long ago as 1934 Germany raced Grand Prix cars which were unpainted, calling them “Silver
Arrows”. Legend has it that at weigh-in, the cars were just a tad over the limit, so they had the idea of
scraping off all the paint and running them in naked aluminium, unpainted. In 1991, Audi exhibited its totally
unpainted AVUS Quattro aluminium concept car at the Tokyo Motor Show. It was an absolute stunner. Look
it up. In recent times there’s Jim Glickenhaus’s P4/5C Competizione race car, all unpainted carbon fibre
and fantabulous-looking. Such cars show that paint on a car is not a sine qua non.
And it’s not just cars. Many planes have been left unpainted, and still are. “Unpainted planes are more
cost-effective and environmentally friendly than painted ones, Japan Airlines said Monday after a nearly 10year
study on the performance of an unpainted 747 cargo plane. The plane, introduced in August 1992, has
helped the company cut back on paint and other chemicals, and has saved up to 2 million yen a year on
fuel expenses as it is about 200 kg lighter without paint.” This is from a 2002 Japan Times Online article.
And in WW-II, USAAF policy established in 1944 dictated that P-38 Lightnings be left unpainted, since the
reduction in weight and drag was a bit of an advantage in combat.
So why do we need to paint anything? Buildings have been left unpainted for millennia, at least on the
outside, and see how good the cathedrals of Europe, and the mosques and temples of Asia, look after
centuries of standing out there, exposed to the elements summer and winter. If walls don’t need to be
painted on the outside, why do they need to be painted on the inside?
And it’s not as if steel structures need to be painted, either. Steel containing approximately 1.5% copper
and up to 1% nickel, no more expensive to produce than other construction steels, taking no longer to
produce than other alloys and less difficult than other alloys to fabricate, can be left unpainted. It has a
structural strength superior to commonly used structural steel (70,000 psi compared with 50,000 psi in the
latter). It was developed by Morris Fine, Professor Emeritus of materials science and engineering at Northwestern
University in Evanston, IL, and his colleague, Research Professor Semyon Vaynman. Because it’s
weather resistant, the North Milwaukee Avenue Bridge in Illinois built with it was left unpainted. This resulted
in about a $300,000 savings in the initial cost, and will lead to even greater savings in the future because
the bridge will not need the maintenance that is typically required for painted steel bridges.
Remember that most layers of paint are just a few thousandths of an inch thick. That’s not much
protection anyway, and needs periodical repainting. And it wouldn’t matter if the paint could be replaced
easily, but it ain’t easy. Painting the Golden Gate Bridge is an on-going task even today: it’s the primary
maintenance job there. Even repainting the inside of your house will set you back a grand or so, and will
take days. You’re not getting a top notch paint job done, mind you: just going over the walls with a roller.
Jeez.
And it’s not as if painted stuff looks better than unpainted stuff: the opposite is the case. Watches,
which are worn as jewellery, aren’t painted, are they? The snazziest computers these days are Apple’s
Macintoshes, also unpainted.
There’s a principle that many architects try—and have tried throughout the ages—to follow: it’s called
“Truth to Materials”. By that is meant that stone should look like stone, wood like wood, brick like brick,
concrete like concrete, plaster like plaster, metal like metal and even plastic like plastic. The point being
that the materials themselves are, when in the right place, inherently beautiful: so why “gild the lily”? Makes
a lot of sense. It seems to have made a lot of sense even two thousand years ago, because the Pantheon
in Rome, commissioned by Marcus Agrippa as a temple to all the gods of Ancient Rome, and rebuilt by
Emperor Hadrian in about 126 CE, is unpainted, and always was: and still looks fabulous after all these
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