By Paul Abelson
Senior Technical Editor
Trucks and trailers are by far one of the most significant investments an owner-operator will make. And to have that investment literally rust away beneath you, especially in three to four years, can be heartbreaking if not financially devastating.
While the technology think tanks have formed task forces to address and correct the problems, there are real-world things you can do to battle the evil rust-jacking beast.
PICK THE RIGHT DESIGN
Design is beyond our ability to change without customization. But when selecting equipment, evaluate available designs.
Before you start evaluating where a new truck or trailer might be susceptible to corrosion, examine your current equipment and get an idea where corrosion might occur. Then compare it with new equipment you are looking to buy.
Look for areas exposed to moisture and make sure they slope downward at least 10 degrees toward the outside or drain holes. These should be located wherever needed to keep water from accumulating.
Remember, corrosion is an electro-chemical process accelerated by electric current. So barriers should keep splash and spray from sensitive areas, especially wiring.
It’s also a good idea to know what materials are more likely to experience corrosion.
Composite materials, including fiberglass, will not corrode. Stainless steel is resistant, but steels differ. Marine grade 300 series is not as hard as 400 series. But 400 series steels have been corroded by the chemicals used in snow fighting. Aluminum can also corrode.
Common galvanized steel is zinc-dipped. According to Adam Hill with Great Dane Trailers, Galvanneal steel has aluminum added to the zinc. It’s fused to steel at 1,000 degrees. Harder than galvanized steel, it has better welding ability, greater resistance to scratching and abrasion and is generally more protective.
Paint is basic protection. It’s a barrier, but susceptible to impact damage and scratching. Once penetrated, rust develops undetected below the surface. Paint has improved with polymer chemistry.
Multipart primers and topcoats give durability and high gloss. Paint and hardener are precisely mixed in the application equipment. Once sprayed on, chemical reactions harden and toughen the paint. Heat improves the result.
Epoxy primers bond to metals, forming impervious, impact- and abrasion-resistant bases for finish coats. Exterior paints are usually urethane. Urethane reacts with moisture, forming a tough, flexible, high-gloss film.
Powder coating, known as Ecoat, is another durable finish. A metal object with an electrical charge is passed through a chamber with oppositely charged paint powder. The powder adheres to every charged surface. When heated, the coating melts and flows, forming a continuous, highly resistant film, according to David Hammes with Waltco Truck Equipment Co.
Protective barriers are shorter-term solutions. They keep moisture and corrosives from bare metal. Plating, waxes, greases and sealants are in this category.
For years, plating has been the way to prevent corrosion on everything from bumpers to nuts and bolts. Unfortunately, plating the great-looking chrome is environmentally harmful. Chromium and chromates are pollutants.
The plating process generates significant hazardous waste. Europe has passed laws to phase out the use of chromium. Hendrickson makes a bumper with a process that essentially fuses polished stainless steel to aluminum. The base aluminum is lightweight, while the shiny stainless looks and protects like chrome.
The highest grades of fasteners now available are plated with chromates. Stainless steel fasteners are strong and corrosion resistant. Soon, stainless steel may be all you’ll be able to buy.
New developments in polymer technology enable protective barriers to be infused into the porous or crystalline structures of metals. Alcoa’s Dura-Bright treatment protects aluminum wheels. The corrosion-resistant wheels can be hosed off rather than needing buffing and polishing.
Grease does more than lubricate. It forms a barrier between contaminants and surfaces to be protected. Nowhere is this more necessary than in wiring, according to Brad Van Riper of Truck-Lite. Electricity accelerates corrosion. Contaminants must be kept out of connections.
Use dielectric greases on all sockets and plugs. Fill the cavity with grease and then make the connection. The pins coming in contact will wipe the grease away from the contact area, but the remaining grease will isolate the contacts and keep contamination out. Be sure to wipe away all grease forced out of the socket by the plug. The exception is Truck-Lite’s triple-sealed plug. In that design, grease creates a hydraulic lock preventing good connection.
Knowing what to specify and how to select your truck is important, but maintaining it, whether new or old, is the secret to keeping your truck from being ravaged by corrosion.
Start by washing it often. Pressure washing removes chemicals before rust starts. Make sure you get under the truck and trailer to flush any areas exposed to road salts. Wash as soon as you can after driving on treated roads.
Inspect – don’t just look at – your truck. Rust can be stopped easily if caught early. Make sure grease fittings and protective boots are in place.
If rust has taken hold, brush, sand or grind to bare metal then prime and paint. Never paint over rust. If you can’t remove it, neutralize it with a compound containing phosphoric acid. They are available at hardware stores and in catalogs. The acid converts the rust to stable iron phosphate. You can prime and paint over it.
Because they are two-part polymers, most urethane paints require professional application. Chassis Saver is a one-part, moisture-curing urethane.
According to Eric Rosenthal of Magnet Paint and Shellac Co., it applies like ordinary paint, but cures similar to polyurethane. It can be applied like ordinary paint, but when the can is opened, curing starts immediately. You have to use it immediately. Any left over will harden in the can.
The seven-pin connector cable creates a special problem. To fit into its cup, the plug must have sufficient side clearance. That clearance allows moisture and corrosives in. John Jacobs of Phillips Industries analyzed the connectors and developed a new barrier – Foam Socket Seal. The soft polymer barrier disc fits inside the cup, attached by adhesive with the contacts protruding through. When the plug is seated, it seals on the disc face, keeping moisture out.
LITTLE EFFORT, BIG SAVINGS
Protecting your truck from corrosion requires awareness and attention. Knowing what to buy is the first step. Look for quality rather than price. Features like stainless steel, sealed lighting and wiring and better finishes may cost more initially, but they far outlast their less expensive counterparts. Keeping it the way you bought it is more critical. Inspect often and maintain immediately. Made routine, it will not require much effort.
If you ignore it, parts that might have been repairable will need replacement.
Paul Abelson may be reached at firstname.lastname@example.org.