Powder coating is an increasingly popular finish option that provides both durability and longevity to various materials, yet can become scratched over time.
Unfortunately, however, its surface can become scratched or damaged over time.
No matter if you want to change the color or enhance the appearance of your product, painting over powder coat is achievable but requires appropriate preparation and techniques. This guide will walk you through everything that needs to be considered before beginning this process.
Preparation
Before applying powder coating over paint, the first step should be surface preparation. A media blaster is an effective tool to accomplish this step as it will effectively strip away existing coating and leave behind a surface on which powder coating can adhere securely.
If your parts have any signs of rust or corrosion, they can be treated with iron or zinc phosphate to increase corrosion resistance and create texture for powder to adhere. Once this process has been completed, rinse and allow them to dry as soon as possible.
Outgassing parts is another essential preparation step. This involves heating them 40-50 degrees above their cure temperature to release any trapped gases within them and prevent warping due to powder pressure. Furthermore, outgassing ensures that parts are completely dry before coating them with powder coatings.
Primer
Powder coating provides a hard surface that’s resistant to scratches, dents, chips and other flaws; however, its hardiness still exposes its metal to corrosion which poses risks for your product. In order to preserve it’s integrity and keep customers satisfied it’s important that these imperfections are resolved as quickly as possible to safeguard its safety.
Before beginning to paint again, inspect the existing coat of paint. If there are areas with less of a coating than others, it may be beneficial to strip away and start over.
If there are no issues, the next step will be primer. A powder coating-specific product must be used, depending on your material and intended use; Keystone Koating suggests using zinc-rich primer on steel products while epoxy primer should be used with aluminum products.
Make sure that you use long, smooth strokes when spraying primer or paint to avoid drips and sags. This will help ensure a quality result!
Paint
Powder coating provides metal surfaces with durable, attractive surfaces that are also corrosion-resistant. Unfortunately, though, powder coat can still become scratched or dinged over time in areas exposed to extreme temperature changes like heat and moisture – these flaws causing the material underneath the powder coat to oxidize and gradually erode away at it over time.
Ideal, another powder coat would prevent further oxidation and restore aesthetic value, but that may not always be possible due to conventional paint’s inability to adhere to powder coated surfaces, while stripping it would be costly and time- consuming. There are still ways of recoating over existing powder coats without resorting to costly methods like sandblasting; proper preparation will allow your new paint job to perform just as effectively as its predecessor! Key here is choosing cleaners or degreasers compatible with powder coating technology – that way your new paint will perform just like its predecessor!
Finish
Powder coating does not emit volatile organic compounds (VOCs), eliminating health and safety risks associated with wet paint while simultaneously offering faster application times of thick and durable finishes.
However, using this process has its challenges. One is difficulty matching colors. These products require special production runs based on plastic composition used in their production and mixing different hues may produce an unsightly speckled appearance that’s difficult to fix.
Make sure the surface you’re painting over is sound and without flaws before starting the project. If the original coated metal project contains chips, cracks or areas where powder coat has failed altogether it may be better to strip and recoat than attempt repainting. Zinsser Degreaser & Cleaner can help ensure proper adhesion between powder coat and metal surface; once sound and sanded you can then apply primer.