Rust never sleeps

Chassis protection begins with special paint processes, such as this used by International Truck and Engine.

Everyone knows that the salt spread on winter roads eats at not only ice but vehicle undercarriages, too. But what about the chlorides now in use other than sodium chloride, such as the calcium chloride and magnesium chloride that are laid onto asphalt to keep ice from forming in the first place?

Opinions vary on how much they contribute to corrosion problems. What’s clear is that more traffic means more aggressive use of these chemicals by road-maintenance departments. That means you need a more aggressive program of truck and trailer cleaning to minimize maintenance problems and protect resale value.

The Technology and Maintenance Council and the Truck Trailer Manufacturers Association are preparing standards for cleaning vehicles, says Howard Yurgevich, vice president of research and development at Hyundai Translead.

Truck, trailer, and component manufacturers have all but invented a new science to fight corrosion in their new products. The industry has created many paints, soft coatings, sacrificial metal treatments such as zinc coatings, and new types of electrical components.

Better corrosion tests are being developed, too, says Nirmal Tolani, manager of metallic materials and specifications for International’s truck group. He works with a crew of 18, tasked with picking the right corrosion-resistant materials.

Manufacturers of the new chemicals say they include corrosion inhibitors in the mix, but some in the trucking industry insist the new chemicals are worse on trucks than plain salt. Steve Kuhn, manager of serviceability design for International’s heavy- and severe-service vehicles, even urges truckers to contact their legislators and demand more benign winter treatments for highways.

Tolani isn’t so sure. “There is no scientific evidence that these materials are any more corrosive,” he says. “We need to do a controlled test. Some suppliers have found no difference.”

There is no correlation between use of vehicles in different states, where different materials may be used, and different rates of corrosion, says Tolani, who believes the aggressiveness of these materials may “have been blown out of proportion by the media.”

Tolani notes that highway chemicals aren’t the only new ones affecting trucks. Truck washes, too, are using more aggressive substances than just soap and water these days, he says.

Trailer manufacturers are, if anything, even more interested in solving corrosion problems than truck makers because their products last so long. Great Dane’s extensive testing has concluded that the new chemicals better adhere to the substrate of trailer surfaces, and “that’s why the new chemicals are worse,” says Rick Mullininx, vice president of engineering.

Those who travel in a dry climate have an advantage because it’s the tendency for these materials to bond with water that makes them effective in clearing roads – and, alas, eating metal. “They have a strong hydrophilicity,” which means they grab water and hold on, Mullininx says.

Chloride on metal combined with water acts a lot like a battery, Kuhn says. “Salt will only work if there is also water to create electrolytic action.” The more humid the environment, the more destructive the chemicals, so it’s always smart to keep the truck as dry as you can, even avoiding the wetter lanes when driving, Kuhn says.

The newer materials are more expensive than salt but are used because they spread farther, Kuhn says. “You can treat more road for less money.”

Another factor is more traffic – too much for old-fashioned treatment to be effective. “Years ago, they would salt after the snow,” Mullininx says. “Now they need to be more proactive, and they treat the roads before the storm. This means more exposure.”

When chemical crews don’t get ahead of the weather, the consequences can be dire, as in the February 2007 fiasco on I-78 in Pennsylvania. Crews waited until a short time into a snowstorm to lay down chemicals, so the treatment would stick to the snow. But that wasn’t soon enough to prevent an accident that stopped hundreds of cars and trucks in a 50-mile backup west of Allentown with no way left to treat the highway. Many travelers were stranded for days. “Not a good day for state government,” Gov. Ed Rendell said.

The Pennsylvania incident notwithstanding, “The states have a better handle on prevention,” says Rod Ehrlich, vice president and chief technology officer at Wabash National.

Unfortunately, that means a road sometimes gets treated because of a prediction of snow that never materializes, needlessly putting even more chemicals on your chassis, Ehrlich says.


YOUR ASSIGNMENTS IN THE WAR AGAINST SALTS
What can you do about corrosion? Quite a bit, starting with your choice of equipment.

SPEC WISELY. Especially if you live or haul frequently in a snow-belt area, you can specify particular design features to help forestall rust trouble. Great Dane, for example, offers stainless-steel rear frames and a corrosion package that includes CorroGuard, a thermoplastic coating. Stainless-steel options on Wabash trailers are especially liked by those who run reefers, because of the need for cleanliness around food, says Rod Ehrlich of Wabash National.

Steve Kuhn of International Truck and Engine recommends long-lasting LED lights, because they’re often especially well-sealed against corrosion.

Remember to replace damaged body parts with those with equivalent coatings and other corrosion-resistant qualities, says International’s Nirmal Tolani. That’s critical to preserving steel cab panels.

Keep potential corrosion in mind when evaluating a basic vehicle design, too. For example, look for adequate drain holes for boxed parts. “They should be a half-inch in diameter so you can see what’s going on inside,” says Howard Yurgevich of Hyundai Translead.

BE A POWER WASHER. The largest single answer is to make a science of what used to be a lazy Saturday afternoon activity: washing your equipment. You need to clean more often and more aggressively. Ehrlich recommends “elbow grease,” and others agree.

“Magnesium and calcium chloride have to be physically wiped off with a towel or hit with a powerful pressure washer,” Kuhn says.

Be especially careful to get debris out of any pockets or crannies formed by the truck or trailer structure.

“Plain water doesn’t do the trick,” Ehrlich says. “You need a cleaning solvent, whether acid or alkaline. That works well to break up the film. But then you need to rinse properly.”

The clean water will neutralize the chemicals used in cleaning. “Use fresh water for the final rinse, and if you recycle water, then use that for the next wash,” Yurgevich says.

Obviously, how long these materials are allowed to sit on the vehicle is critical to how much damage they do. “After salt exposure, wash the truck or trailer as soon as possible,” says Rick Mullininx of Great Dane.

BUT NOT TOO POWERFUL. Overly aggressive cleaning can be a problem, too. Yurgevich recommends avoiding harsh cleaners such as organic solvents because they are “too strong and remove coatings and corrosion resistance.”

Pressure washers produce up to 3,500 psi, so “don’t hold the nozzle too close,” Ehrlich says. “The blast can damage the surface and even take paint off and damage seals.” Hyundai Translead’s maintenance specs advise sticking to 2,000 psi at 2 to 5 gallons per minute while maintaining at least 8 inches between the nozzle and surface. Point the washer at least 90 degrees away from lapped joints so water won’t be forced in.

BE ATTENTIVE TO DRYING. “Don’t let the water dry on the surface,” Ehrlich says. “A puddle will leave deposits.” On horizontal surfaces, use something “like an air knife or squeegee to push the water away,” Ehrlich says.

If this seems like too much trouble, consider the benefits, especially for trailer owners. “Keep it clean and properly rinsed and dry, and it will last forever,” Ehrlich says.


HOW SERIOUS CORROSION IS REPAIRED
Technician John Engle cranked up a 200-hp Caterpillar-powered air compressor and donned a protective suit to show how restoration work is done at Kolors East in Myerstown, Pa., a large shop that does corrosion warranty work for truck manufacturers.

He loaded several hundred pounds of sand into a pot. Then, grabbing a sandblasting gun fed by a long hose, he used a stream of high-velocity sand, accelerated by 100-psi air, to strip the rust from an aging dump trailer.

Kolors co-owner Andy Armstrong pointed to the frame of a 2001 truck the company had just repainted. While frames don’t typically rust through, a clean and painted frame is essential to resale value. Kolors removed tanks and other parts that were in the way, sandblasted the metal, sealed cracks where moisture would form, primed the bare metal, and refinished the frame with DuPont Imron paint blended by computer.

The frame looked brand-new, and the $2,800 bill was a good reminder that keeping the truck clean can save the owner big money down the road.


THE FIGHT STARTS AT THE FACTORY
Fortunately, truck and trailer manufacturers have not been sitting still while corrosion gnaws at their products.

“I’ve been at International 34 years, and the materials have come a long way,” says Nirmal Tolani of International. One of the most effective and basic changes has been to use zinc coating on both inside and outside surfaces of almost all body panels, he says. “Many manufacturers coat the panel only on the inside, believing the corrosion only starts there. Coating body panels on both sides is an International first in a truck.”

Zinc doesn’t just cover the steel but works like a battery, sacrificing its structure to protect the metal underneath. If its surface gets scratched, its healing properties keep rust from starting.

The primer coat is applied with electro-coating that uses current to attract the paint to all surfaces and force it into all nooks and crannies, Tolani says.

“We must design our trucks for all locations,” Tolani says. “Attention to paint, sealer, pre-treatment of metals, and design – for example, joints that don’t trap dirt and moisture, and how well you provide drainage from critical areas – these are all critical elements.”

Hyundai Translead provides a zinc coating through hot-dip galvanizing. “You start with bare metal,” says Hyundai Translead’s Howard Yurgevich. “It is then welded, and finally it’s dipped into zinc, so the coating gets everywhere. Hot-dip galvanizing even seals the welds. You can’t beat it except with stainless.” The landing gear gets galvanized, too.

“Our standard undercoatings are better than paint,” says Rick Mullininx of Great Dane. “Paint is brittle, while undercoating is soft and flexible, so it resists damage and dents. It actually feels waxy to the touch.”

“We have baked-on powder coatings that use no paint solvent,” says Rod Ehrlich of Wabash National “We use sandblast preparation so the surface is like sandpaper, and then we apply a thermoplastic coating.” Parts then are baked at 350 degrees to melt the powder into a smooth coating and fuse it to the metal. As a result,” Ehrlich says, “This process has more than seven times the resistance to corrosion of past processes.”

Wabash also applies coatings “component by component” and has moved wiring connectors well back from each lamp, so that corrosion in one won’t ruin the other, and the corroded part can easily be repaired, Ehrlich says. The sealing of plugs has been improved, too, rather than relying solely on technicians to fill the connection with protective dielectric grease.

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