How We Stop Trucks & Trailers Rusting

Your trucks and trailers are one of your most expensive investments, making a long-lasting clean finish more important than ever. Corrosion and rust is the quiet killer that hits your public image, equipment resale value, and attracts the attention of VOSA. Keeping it at bay is a long-term battle that some equipment isn't ready to fight. Surface treatment and anti-corrosion is key, but it's not all the same. I'm going to run through why this matters, the four we use, and the questions to ask before ordering your next truck or trailer.

Why Worry About Rust? Simply put, rusty equipment looks terrible and it's because of what it's associated with: decay, neglect. And the worst part is there's little you can do about it. Your equipment is set on that path from the day that you buy it and it's difficult and expensive to correct. And we're speaking from experience. You might see some older Kel-Berg aggregate trailers with pretty poor chassis paint. That's because for a period of time, the processes we used for some trailers were not up to par. From this experience, we know what makes equipment last and what doesn't. So, here's what the proper approach looks like and where it's best used. We use a combination of paint, sacrificial layers, and surface preparations because no single method does everything. Which combination we use depends on the component and what it's going to face. Here's how that works in practice.

Process 1: Shot Blasting + 2K Paint Shot blasting and two-pack painting is the most common process and most manufacturers are using it. Sand is blasted at the surface which does two things. It strips everything off: mill scale, existing rust, moisture, any contaminants. This leaves a clean surface ready for coating, preventing corrosion from taking place behind the paint. And second, it roughens the surface giving the primer and the top coat something to mechanically bond onto. Once the shot blasting's done, it's etch primed and finished with two-pack paint. Two-pack or 2K is a two-component paint. You mix top coat with hardener just before spraying and when they combine they trigger a chemical reaction that permanently hardens the paint. Once it's cured, it can't be softened or dissolved. That's what gives it the hard, chip-resistant finish that withstands road salt, rain, frost, and UV. All things these vehicles are in every day. Every Kel-Berg tipping body, grab loader body, vacuum tanker, and mixer drum gets this treatment as standard.

Process 2: Shot Blasting + KTL + 2K Paint But on our trailers, the chassis goes through something different entirely. Most trailer chassis are shot blasted, primed, and painted. On a Kel-Berg chassis, it goes through an 11-stage process that chemically bonds the primer to the steel, coats every surface inside and out, and finishes with a powder coat that's harder than 2K paint. First, the chassis is shot blasted and it's degreased, rinsed, and zinc phosphated. This is a chemical process that converts the steel surface into zinc phosphate crystals, giving the primer a far stronger foundation than bare blasted metal. Then, KTL. The entire chassis is submerged in a primer bath and an electrical current draws the primer onto every conductive surface. Finally, the chassis is powder coated on top of the KTL primer. Powder coating is a little bit harder and more durable than wet spray paint. So, by the time we're fitting your chassis out, it's been shot blasted, chemically treated, KTL primed, and powder coated. And that's every surface inside and out. But some components don't need a colour at all. They just need protecting. And for those, there's a process that looks after itself.

Process 3: Hot Dip Galvanisation Hot dip galvanisation. The component is submerged in a bath of molten zinc, creating a sacrificial zinc layer over the steel. It's called sacrificial because the zinc corrodes in place of the steel. Zinc is more electrochemically active than steel, which really just means it's more reactive. Doesn't sound ideal, but the key difference is what it corrodes into. Steel corrodes into iron oxide, which is rust. Rust is porous, flaky, and doesn't stick well. So, moisture gets through it and reaches fresh steel underneath, resulting in the corrosion going deeper and deeper and deeper. When zinc corrodes, it forms zinc oxide, which then reacts with moisture and CO2 in the air to form zinc carbonate. This is that dull matte grey patina you'll see on older galvanised components. Stable, dense, and tightly bonded to the zinc beneath it, forming a protective layer. Galvanisation is a well-known process, but not everybody uses it as liberally as we do. We galvanise as much as we can on tippers, grabs and vac tanks: subframes, headboards, rear wings, push bars, underrun bumpers, side guards, ladders, shovel racks, light brackets. The list goes on. There are limitations though. Galvanisation gives a surface that paint doesn't naturally like. Without careful pre-treatment, paint adhesion can be poor. That's why we reserve hot dip galv for components that don't need a painted finish on top. In extremely aggressive environments, pure galvanisation can reach its limits. So for this, we turn to metallisation.

Process 4: Metallisation + 2K Paint Metallisation brings the benefits of both paint and galvanisation together. Sacrificial protection that can be painted over. It's needed because some environments are just too aggressive for galvanisation alone. Concrete mixers are a prime example. The concrete itself is highly alkaline and the chemicals used to clean the drums and chutes are often highly acidic. So the superstructure is being attacked from both ends of the pH scale, meaning the zinc galvanisation would start to corrode incredibly quickly. Instead of dipping the component in molten zinc, we're spraying a molten zinc-aluminium alloy onto the surface. There are two key differences to galvanisation. First, the alloy is zinc-aluminium, not pure zinc. The aluminium forms a very stable oxide layer at the surface, which is more resistant to many corrosive environments than pure zinc. That means the coating itself holds up in conditions where standard galvanising would struggle. Second, the texture. Because the alloy is sprayed on as molten droplets, you get a naturally rough profile. So paint bonds very strongly to metallised surfaces. So you've got a more chemically resistant sacrificial layer underneath with a painted finish on top with a really strong bond. There is no moisture getting under that. Now, this is a specialised process and not many manufacturers are using it and even fewer apply it as extensively as we do across the full installation: subframe, pedestals, hoppers, chutes, not just the high-wearing areas. Here you can see an older mixer that we've recently taken in part exchange and you can see how the paint's held up. So, that's the four processes. None of it is an upgrade. None of it is an add-on. Every one comes with a 2-year anti-corrosion warranty on the body paint. It's all standard on Kel-Berg products as I've described it. So, if you're comparing quotes right now, it's worth getting into what anti-corrosion is being used because like I said, by the time you find out that it wasn't good enough, it's usually too late to do anything about it.

4 Questions To Ask Before Buying Here are four questions worth asking. How much of the ancillaries are galvanised? Is it a few pieces or as much as possible? On a mixer, is the superstructure metallised or just painted? And is that the full installation or just selected areas? On a trailer, is the chassis KTL coated or only blasted and painted? Is the body shot blasted before painting or just sprayed straight onto the steel? The answers will give you an idea of how long that equipment is going to look right and hold its value. If you've made it this far, let me know your thoughts. When you're buying equipment, is anti-corrosion something you're paying attention to? Let me know in the comments.