Techniques to Battle Corrosion on Trucks a Hot Topic Among Maintenance Directors

RALEIGH, N.C. — Maintenance directors meeting here shared techniques for combating rust and other forms of corrosion, which they said are a plague to trucks.

Seven of the 12 permanent study groups of the Technology & Maintenance Council had a task force meeting on a type of corrosion at the group’s fall gathering, Sept. 19-22.

A major topic was magnesium chloride, a road de-icer they said appears to make the challenge of fighting corrosion insurmountable now. TMC, which is a division of American Trucking Associations, also has a Corrosion Control Action Committee.

“Corrosion affects every part of our trucks and trailers,” said Todd Cotier, maintenance director of Hartt Transportation Systems, Bangor, Maine, and chairman of the corrosion committee. “Any metallic component from wiring to wheels can get it.”

Although wires are insulated and under some form of cover from rain, they can suffer damage through the process of wicking — most commonly seen in paper towels. Fred Kelley, a Prestolite Wire engineer, offered a demonstration at an electrical systems meeting.

Kelley took pieces of wire and bent them like the letter “J.” The small ends went into a cup of coffee while the long ends hung down around the cup’s side. After he finished talking about wire gauge and insulation, coffee was dripping out of the long ends onto the table, having passed from the cup through the length of the wire.

“There’s air between the strands of the wire, and condensation helps turn the wire into a straw,” Kelley said, adding that an anti-corrosion treatment is available that coats the wire with a powder before insulation. That minimizes the amount of air left inside.

At a technical session of Cotier’s committee, engineer Marvin Shelton of PPG Industries said the search for materials that are ideal for a particular job brings about corrosion as an unintended side effect. If two different metals touch each other — such as steel screws holding together aluminum plates — and that common area then becomes wet with salt water, corrosion follows.

“Nature provides the electrolyte for this galvanic corrosion with rain or snow, and de-icing salts such as magnesium chloride, calcium chloride and rock salt accelerate it,” Shelton said.

Following Shelton, Kevin Irving of AZZ Galvanizing Services advocated for his industry, which does hot-dipped galvanizing. That process entails dipping pieces of steel into molten zinc and developing a coating of less than 1% of one inch. Once completed, the zinc shield sacrifices itself to the elements, leaving the steel intact.

Trailers get hammered relentlessly, said Lori Coleman, fleet manager for distributor Gordon Food Service, Grand Rapids, Mich. Gordon’s service area of the Great Lakes to northern Alabama coincides with the nation’s most aggressive rust zone.

Gordon washes its 1,100 day-cab tractors daily and its 1,700 trailers at least twice a week, trying to keep rust at bay, but as a rock star once observed, “Rust never sleeps.”

“We are continuously cleaning, cleaning and cleaning,” Coleman said. Electrical plugs — a prime example of dissimilar metals touching — are particularly troubling, she said, adding that wiring harnesses are likely to become victims as well.

Coleman showed pictures of trailers with corrosion problems, and some of them were bought new as recently as 2007-2010.

Utility Trailer Manufacturing Co. uses hot-dipped galvanization, said vice president of engineering Jeff Bennett, as well as paint and wax-based coatings.

At the new products meeting, engineer Tim Brune of Automotive International said his company operates as ValuGard and sells a cavity wax to coat metal and isolate it from air and water. The company also makes wax-based asphalt coatings.

“Magnesium chloride is basically ‘liquid rust.’ It clings to everything and it attracts water — and it does not wash off easily,” Brune said, adding that tractors and trailers can be harmed even more when they drive through counties using different de-icers. Picking up all three chloride salts — calcium, magnesium and sodium — makes corrosion even worse, Brune said.

While washing should help, Cotier recommended high-volume, low-pressure washing, as high pressure is likely to drive bits of magnesium chloride deeply into crevices, where they will keep eating steel.

“You don’t want to drive this further in. Instead, you want to flush it out, and we need to find out how to neutralize this,” Cotier said.