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Scientists use laser weapons to combat graffiti

graffiti

April 29, 1996
Web posted at: 9:00 a.m. EDT

From Correspondent Susan Reed

SAN FRANCISCO, California (CNN) -- Graffiti is not only an eyesore, it's a kick in the pocketbook. Across the United States, the cost of cleaning up graffiti is estimated at $7 billion a year.

Cities are at their wits' end. Chicago and Phoenix have banned aerosol spray paint cans. Other cities require property owners to remove graffiti within 10 days or face a fine and/or jail.

And in California, the state legislature is considering a bill that would ban all spray paint cans unless they are attached to a power source like electricity.

The graffiti problem begs the question: wouldn't it be wonderful if it could just magically disappear with no environmentally hazardous residue left behind?

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Scientists at Lawrence Livermore Laboratory have beat their swords into plowshares and turned the weapons of the Cold War -- star wars lasers -- into inventions the public can use. In this case, the weapon has become a graffiti blaster.(921K QuickTime movie)

Peter Celliers explains that the blaster works by focusing a beam on a mirror and "making the beam walk across the brick."

"This is a very large pressure wave, which pulverizes the material on the surface," he says. "It breaks it off in little pieces and comes off as a dust."

The dust is vacuumed up, leaving the surface underneath the graffiti unscarred -- which is not possible with either sand blasting or spraying baking soda, two common clean-up methods.

Mike Campbell, director of laser research at Lawrence Livermore, says that the blaster can be much faster -- and cheaper.

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"We believe it can be as cheap or cheaper," he says. "And it can be environmentally beneficial."

But there is one big problem -- cost. So far, only laboratory equipment has been used to demonstrate the graffiti blaster. A commercial device would cost about $250,000 -- too much even for Los Angeles, where the county spends close to $100 million a year on graffiti removal.

But four years ago, baking soda spraying cost that much. Now the machinery for that process is a 16-pound unit that costs $600. Livermore Lab scientists are getting that industry involved, hoping to bring the cost down and make graffiti removal as easy as it is to spray it on.

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