Preventing Trailer Corrosion: Spec'ing Against Corrosion

Salt-caused corrosion and how to beat it was a principal theme at the Technology & Maintenance Council's annual meeting in February, and no one considered the balmy temperatures and utter lack of frozen moisture outside the Orlando Convention Center in Florida to be in any way ironic. 

Use of calcium- and magnesium-chloride deicers by road crews in most states and municipalities continues to literally erode metals in trucks and trailers and shorten the vehicles' lives, TMC fleet-manager members complained in several sessions. To what extent varies with the operation and its location. Several managers said they have shortened trade cycles by a year or more while others say they have to cope because their companies won't spend the money for more frequent equipment purchases. 

A meeting of the Corrosion Control Action Committee, a group recently formed by Roy Gambrell of Truck It Inc., in response to members' heightened concerns, saw attendees verbally wringing their hands over damage to vehicles and the extra cost of protective measures. These range from protective coatings offered by manufacturers to the spec'ing of aluminum and even stainless steel instead of regular steel. 

Undercoatings can work or not, depending on the materials and how they're applied, and can add many hundreds of dollars to the cost of a new vehicle. An in-service truck costs even more to undercoat because it must first be thoroughly cleaned or blasted. 

Aluminum wheels stand up better to aggressive road salts than steel wheels, but cost about $2,500 more per vehicle. Stainless steel has long been a cure for the unsightly rusting of doors and door headers on trailers, but is too expensive for most fleet people to consider. Also, warned one manager, there are different grades of "stainless" and the lesser ones will rust. One must know his specifications to get the performance he wants. 

Fleet managers should also spec materials as to their performance in industry salt-spray tests, one manufacturer's representative advised. There are different tests and, although a long-used one has shown to be inadequate, another - SAE J2334 - can correlate to real-world use. Gambrell and other fleet people protested that they shouldn't have to possess such arcane knowledge, but suppliers countered that it would pay to speak the manufacturing industry's language in specifications.

Several of TMC's study groups formed task forces to investigate corrosion and how to deal with it. One is Trailer Corrosion Control, headed by Al Anderson of Consolidated Metco, whose members listed the many components that see damage from road salts. Among them are floors, frames, walls and bulkheads, doors and door frames, rear bumpers and underride guards, landing gear, the upper coupler area, suspension parts, wiring and lighting, and exposed air tubing including gladhands. 

One reason that calcium- and magnesium-chloride salts cause so much damage is their ability to cling to metals and absorb moisture from the air, participants said. These salts cannot be sprayed off like common rock salt (sodium chloride) can, and they hide in nooks and crannies. Direct brushing or high-pressure water spraying is needed to remove the salts, but too high a pressure can damage wheel seals and other parts. The aggressive salts continue to corrode metals at higher temperatures and after the roads are dry because they grab humidity and, in effect turn wet and stay active. 

The organized trucking industry must lobby state and local officials to get them to use more benign chemicals to deice roads, TMC members said in this task force meeting and others. One substance is de-sugared beet juice being tested in Ohio and elsewhere. Other members felt that protests would do little good because road authorities preach safety that comes from bare pavement - "If we save only one life, it will be worth it," the cry goes. 

However, reports of contaminated water supplies and health problems among drivers and mechanics are beginning to surface, several members said. Road salts have been blamed for poisoning wells in the Northeast and West, and workers have begun to suffer coughing and breathing problems because of steady exposure to the chemicals. As unfortunate as this might be, such reports, if verified, could capture the public's imagination and result in government action. Stay tuned.