If you’ve ever worked in industrial equipment manufacturing, material handling, or even heavy agriculture, you’ve probably come across bimetal side plates. Those heavy-duty components, designed to resist wear in high-friction environments, are a staple on conveyor systems, excavator buckets, and industrial mixers. As someone who’s been a bimetal side plates supplier for over 12 years, I get dozens of questions every week from customers: “Can these things be painted?” It’s a reasonable question—after all, most industrial parts get painted, whether for corrosion protection or brand visibility. But bimetal side plates aren’t your average steel bracket, and the answer isn’t as simple as a yes or no. Let’s break this down, from the science behind why bimetal side plates are special to what’s actually possible when it comes to painting them. Bimetal Side Plates
First, let’s recap what bimetal side plates are, because that’s the foundation of everything we’re talking about. Unlike single-metal plates made of just carbon steel or stainless steel, bimetal side plates are engineered with two distinct metal layers bonded metallurgically under extreme heat and pressure. The base layer is usually a tough, affordable carbon steel, which provides structural rigidity and the ability to be machined into precise shapes (like the side frames of a conveyor or the walls of an excavator bucket). The working layer—what makes the bimetal side plate useful—is a harder, more wear-resistant alloy, often high-chromium cast iron, chromium carbide, or a similar abrasion-resistant material. This dual-layer design is the whole point: you get the strength of steel for load-bearing, plus the wear resistance of a hard alloy that can last 3 to 10 times longer than a single-metal plate in abrasive conditions (like moving gravel, concrete, or mining ore). That combination is why bimetal side plates are in such high demand, and why painting them isn’t the same as painting a plain steel part.
So why would someone want to paint a bimetal side plate in the first place? There are two main reasons. First, even though the working alloy is wear-resistant, the base carbon steel layer is vulnerable to corrosion, especially if the equipment is used in humid, salty, or chemical-rich environments. If the wear layer only covers part of the side plate, the exposed base steel can rust over time, which weakens the component and shortens its lifespan. Second, some customers want to add their own company’s branding or safety markings—like high-visibility yellow for heavy machinery, or warning labels for industrial equipment. Both goals are valid, but painting bimetal side plates requires careful consideration of how the two metal layers interact with paint, and how the harsh environments these parts live in will affect the finish.
Let’s start with the technical hurdles. The biggest challenge when painting bimetal side plates is getting the paint to adhere properly to both metal layers. Each layer has a very different surface chemistry and texture, which means standard surface preparation and paint systems often don’t work. The carbon steel base is relatively smooth, with a uniform grain, while the wear-resistant alloy layer—high-chromium cast iron, for example—is porous, rough, and has a different chemical composition (higher chromium, lower carbon than carbon steel). If you don’t treat each surface differently, the paint will either flake off the carbon steel side within a few months, or bubble and peel on the porous wear layer as air and moisture get trapped in the tiny gaps between the alloy grains.
Another factor is the operating temperature of the bimetal side plate. Many of these parts are used in applications with extreme heat—like the side plates on cement mixers, which can reach 200–300°F during operation. Standard interior or exterior house paint won’t hold up to that kind of heat; it will melt, discolor, and peel. Even industrial-grade epoxy paint can fail if it’s not rated for high temperatures. Then there’s the abrasion factor. Remember, the whole reason the side plate is bimetal is to resist wear from constant friction. If you put a thick paint coating on the wear layer, that coating will wear away in weeks, leaving your expensive bimetal plate unprotected and your time and money spent on paint wasted. That’s a big mistake I’ve seen customers make over the years: they think more paint equals more protection, but on a wear part, the paint is just an extra layer that gets scraped off before the plate does its job.
Now, for the good news: painting bimetal side plates is possible, if you do it right. I’ve worked with our engineering team to develop a process that’s been tested on hundreds of plates for customers in mining, agriculture, and material handling, and it works for both corrosion protection and branding. Let’s walk through the steps that make this possible, because it’s not just “brush on paint and go.”
First, surface preparation tailored to each metal layer. This is the most critical step, and it’s where most DIY or low-quality paint jobs fail. For the carbon steel base layer, we do a standard blast cleaning with angular steel grit, which etches the surface to create small, rough pockets for paint to grip. Then, we apply a zinc-rich primer specifically formulated for carbon steel. This primer not only improves adhesion but also adds extra corrosion protection to the base layer, which is key for side plates exposed to rain, snow, or salt.
For the wear-resistant alloy layer, we can’t use the same blast cleaning method. The porous nature of high-chromium cast iron means steel grit can get trapped in the tiny pores, leading to adhesion issues later on. Instead, we use a glass bead blast, which is finer and rounds out the pores without leaving behind debris. Then, we apply a specialized epoxy primer designed for cast alloys, which penetrates the small gaps in the wear layer and creates a strong bond between the alloy and the topcoat. This primer also resists the high temperatures and abrasion that the wear layer sees, so it won’t peel or flake when the side plate is in action.
Next, choosing the right topcoat. This depends on what the customer’s goal is. If they just want to add branding or safety markings, a polyurethane topcoat rated for industrial use is perfect. Polyurethane is tough, flexible, resists UV damage (so it won’t fade in outdoor applications), and can hold up to temperatures up to 250°F, which covers most common bimetal side plate uses. If the main goal is corrosion protection for the base steel layer in harsh environments (like coastal locations or chemical processing plants), a two-part epoxy topcoat is a better choice. Epoxy is even more corrosion-resistant than polyurethane, though it’s a little less flexible, so it works best for side plates that aren’t going to be subjected to constant impact or bending.
Wait, but what about painting the wear layer? As I mentioned earlier, putting a thick topcoat on the working alloy will wear away. So we always recommend only painting the non-wear areas of the side plate. That means the edges, the mounting holes, and any part of the plate that doesn’t come into contact with abrasive material. The actual wear surface—the part that’s supposed to resist friction—should never be painted. That’s a rule of thumb I’ve stuck by for 12 years, and it’s saved dozens of customers from wasting money on paint that doesn’t last. If you have a custom side plate design where the wear surface is partially exposed, we can mask that area during the painting process to make sure no paint gets on it. That’s a small step that makes a huge difference in the lifespan of both the paint and the side plate.
I also want to address a common myth I hear all the time: “Painting a bimetal side plate will void the manufacturer’s warranty.” That’s not true, as long as you’re using a reputable supplier and following the right process. When bimetal side plates are made, the engineering team designs them to be compatible with standard surface treatments, including painting. In fact, many major bimetal manufacturers offer custom painting services as part of their product line, because they know customers want branding or corrosion protection. The key is to work with a supplier that understands the metallurgy of bimetal, not just a general painter who treats all metal the same.
Let me share a real example to put this in perspective. Last year, we worked with a large agricultural equipment manufacturer that needed bimetal side plates for their new line of combine harvesters. The side plates went on the grain conveyors, which are exposed to dirt, rain, and fertilizer chemicals during harvest season. The customer wanted the side plates painted their company’s signature blue, plus high-visibility white safety markings along the edges. If we had used a standard paint process, the blue paint would have flaked off the carbon steel base within one harvest season, and the markings would have worn away on the edges. Instead, we used our tailored surface preparation: glass bead blast on the wear alloy, steel grit blast on the base steel, specialized primers for each layer, and a high-heat polyurethane topcoat. We masked the entire wear surface of each plate to prevent any paint from getting on the working alloy. The plates have been in use for over a year now, and the paint is still holding strong—no flaking, no fading, and the wear surface is performing exactly as we designed it. The customer ended up ordering 2,000 more plates this year, which is a testament to how well the process works.
Another example is a mining customer we worked with in Colorado. Their bimetal side plates were going on conveyor systems that moved salt, which is extremely corrosive to steel. The original plates had no paint, and the base steel layer started rusting within six months, which weakened the plates and led to unexpected downtime. We painted only the base steel layer (masking the wear alloy completely) with a two-part epoxy primer and topcoat. After 18 months, the plates show no rust on the base steel, and the paint is still intact. That’s a huge win for them, because unplanned downtime in a mine can cost tens of thousands of dollars a day.
Now, what about when you shouldn’t paint your bimetal side plates? There are a few cases where painting isn’t the right choice. If your side plate is going to be used in an environment with very high temperatures (over 350°F), standard paint systems won’t hold up, and you’ll end up with peeling paint. In that case, hot-dip galvanizing or a ceramic coating is a better option for corrosion protection. If your side plate’s wear surface is exposed to extreme impact—like on an excavator bucket that’s slamming into rock—paint will chip almost immediately, and you’re better off leaving it uncoated except for the base steel layer. And if you’re just using the side plate in a dry, indoor environment with no exposure to corrosive elements, painting it might be unnecessary, as the base steel won’t rust quickly enough to affect performance.
At the end of the day, the answer to “Can bimetal side plates be painted?” is yes—when done correctly, it’s a great way to add corrosion protection, branding, and safety markings without sacrificing the performance that makes bimetal plates so valuable. But it’s not a one-size-fits-all process, and it requires working with a supplier that understands both the metallurgy of bimetal and the specific demands of your application. If you’re considering painting your bimetal side plates, or if you have questions about custom painting options for your project, we’re here to help. We’ve spent years refining our painting process for bimetal components, and we can work with you to find the right solution that meets your needs and keeps your equipment running smoothly.
When you’re investing in heavy industrial components like bimetal side plates, you want to make sure you’re getting every bit of value out of them. Painting is a simple, cost-effective way to extend their lifespan, improve their performance, and add the custom details that your business needs. Don’t let the myth that bimetal can’t be painted stop you from getting the most out of your parts—just make sure you work with a knowledgeable supplier who knows how to handle the unique needs of bimetal metallurgy. If you’re ready to discuss custom painting for your bimetal side plates, or if you have questions about our products and services, reach out to our team for a consultation. We’re always here to help industrial professionals make the right choices for their equipment.
Bimetal Bushings References
ASM International. (2005). Bimetallic Materials: Properties and Applications. ASM Handbook Volume 2: Properties and Selection: Nonferrous Alloys and Special-Purpose Materials.
NACE International. (2018). Surface Preparation and Coating Requirements for Industrial Components.
Manufacturers Standardization Society. (2020). Design Guidelines for Bimetallic Wear Components.
Qingzhou Baiyun Anti-friction Products Co., Ltd.
With abundant experience, we are one of the most professional bimetal side plates manufacturers and suppliers in China. Please rest assured to wholesale customized bimetal side plates at competitive price from our factory. Welcome to contact us for quotation.
Address: Linglongshan North Road (south of the railway bridge), Economic Development Zone, Qingzhou City, Weifang City, Shandong Province
E-mail: byantifriction@gmail.com
WebSite: https://www.baiyunbimetal.com/
