Manufacturers across a wide array of industries are turning to powder coating as their preferred method to protect their equipment. That’s because the process ensures better adhesion and coverage compared to traditional wet paint applications. With industrial powder coating, the completed piece has a highly durable finish that can resist numerous environmental and chemical hazards. It’s no wonder, then, that the procedure has become standard for agriculture, defense and automotive sectors.
However, the enhanced durability of these finishes would not be possible without a robust powder coating pretreatment process. This differs from the typical paint pretreatment, but ultimately leads to a stronger bond between the substrates and coatings. What follows is a brief overview of how coating pretreatment works and why it is necessary to achieve the best overall results.
What is Powder Coating?
Before learning about the powder coating pretreatment system, it is important to understand what powder coating is and how it is applied. Unlike standard paints, this coating is a dry powder consisting of polymer resins, pigments, curatives and other added ingredients. It resembles baking flour in many ways, especially with its uniform consistency and fine particles.
To cover a piece of equipment, the mixture is forced through a spray gun that applies an electrostatic charge to each particle. To help attract the powder to its surface, the unit is usually grounded. After the entire surface is covered, the part is placed in a curing oven. There, the intense heat causes a reaction that permanently bonds the powder and creates a seal. Once completed, the finished components are ready for assembly or sale.
How Pretreatment Works and Why It Matters
Just as you would sand or use a primer before applying liquid paints, pretreating surfaces is crucial to ensure that the powder coating sticks. Without this critical step in the powder coating process, impurities on the substrate may interfere with the integrity of the finish. Professionals understand the importance of creating the cleanest possible exterior before attempting to coat it.
In cases where a fresh coat is being applied to an existing component, the first step should be to remove any existing finishes and/or rust. In an industrial environment, this typically is accomplished through sandblasting. For newly manufactured products, sandblasting is unnecessary, so these units move to the next step: chemical cleaning. Most powder coating pretreatment chemicals are alkaline based in order to remove any oils, dirt or other contaminants.
Once the chemical cleaning is finished, the next step is to etch the surfaces and apply a conversion coating, such as iron or zinc phosphate. This is to provide a layer to which the powder can adhere with greater success. A final rinse in water treated with an acidic solution completes the pretreatment process. The item is now ready to be coated.
Pretreatment for Different Part Conditions
Part of what makes Rhinehart Finishing the best choice for pretreatment is our deep knowledge. We understand that selecting the right process has more to do with the condition of the part than the material. For instance, parts that are used or already coated should be cleaned and pretreated using sandblasting to remove rust and the existing finishes. On the other hand, newly manufactured components must undergo chemical pretreatment to ensure the removal of oils, dirt and other contaminants that may be left on the surface.
The goal in any surface preparation scenario is to produce a clean, reactive metal surface that will enable the most effective coating adhesion and ensure the highest levels of durability. Without the proper surface prep process, there’s an elevated risk of premature part failure. This is what makes our in-house expertise so valuable for our clients.
Benefits of Proper Pretreatment in Industrial Applications
Pretreating components before applying powder coating is essential if you want to achieve the best overall results from the process. By removing any contaminants or impurities on the surface of the part, there’s a much better chance that the coating will adhere properly to the substrate. This is critical for preventing issues such as flaking, bubbling or delamination that can have a negative effect on the performance of the coating.
This is especially important for parts that will be exposed to harsh environments. If a powder coat begins to separate from the surface due to any impurities between them, it can leave areas of the metal exposed. This could lead to premature failure due to corrosion or excessive wear and tear. By following proper pretreatment procedures, industrial operators can experience longer lifespans, reduced maintenance requirements and higher overall quality from their components.
Other benefits of proper pretreatment include a more consistent coating thickness across parts. Not only does this help ensure the ideal performance for the coatings, but it also helps provide a uniform appearance that enhances the aesthetics of the equipment.
Choose Rhinehart Finishing
As part of our comprehensive powder coating capabilities, Rhinehart Finishing follows an extensive TT-C-490 Type I pretreatment protocol that goes above and beyond industrial powder coating standards. In fact, we use a zinc phosphate coating system that is certified by the Department of Defense and approved for TACOM-grade military applications. This level of corrosion protection can potentially extend the life of your equipment and enable it to withstand the wear and tear of repeated operation. From military and defense applications to heavy trucks and construction equipment, our zinc phosphate pretreatment ensures the best overall results for our customers across multiple industries. This enhances our capabilities in powder coating for manufacturing equipment and many other applications.
The professionals at Rhinehart Finishing have considerable experience with the common types of coatings, including epoxy, polyurethane and hybrids. Plus, our state-of-the-art production facility includes one of the most advanced coating booths in the industry. We also offer one of the largest product window sizes in the Midwest, capable of handling items up to 12’ x 3’ x 6’. Trust Rhinehart Finishing for superior, expert pretreatment service.