How to Apply Paint to Powder Coated Metal Sheets

 Powder coating has many advantages and disadvantages as a metal finish. It is often chosen for its durable finish, environmental friendliness and lower variable cost compared to liquid coatings. However, even powder coatings are susceptible to wear and damage over time.

Whether it is to prevent oxidation of the iron substrate or to restore the appearance of the product, there is a good reason to apply a liquid coating to a powder coated surface. If you want to continue painting, the short answer is yes, however, you must be aware of some precautions.

 

 

Challenges of applying spray paint

Adhesion - Adhesion is the ability of a coating to bond to a specific surface. The challenge with adhesion when applying paint over powder coatings is that powder coatings can often produce a very flat, smooth surface. This can present a challenge when trying to get a liquid coating to bond properly to the substrate underneath.
Matching coating properties - Powder coatings are highly resistant to scratching, abrasion and weathering. When trying to paint over an existing powder coating, you often want to have a liquid coating with similar performance characteristics to the powder coating, even though you usually cannot achieve the exact performance of the original powder coating.

 

 

How to overcome the challenge

Properly prepare the surface

Since powder coatings usually form a smooth surface after application, you must rough up the surface to create a surface profile so that your coating can create adhesion. You can create adhesion by sanding bare areas as well as the edges of bare areas that still have the powder coating on them. As a rule, you should use fairly light sandpaper. After sanding the area to be painted correctly, you will need to wipe the area with a suitable solvent cleaner.

 

Choosing the right coating

To maximize the life of your repair job, you need to choose a coating system with performance characteristics similar to those of the original powder coating. The ideal coating system will depend on the environment in which your product will function and the primary focus of the product, both in terms of appearance and performance. Ultimately, you can consult with Manufacturer LITONG to ensure that the coating will last as long as your original powder coating.

 

Applying Coatings

There are a variety of ways to apply coatings, and the right method for your product depends on the amount of coating you need to perform and the finish you want to achieve. To get a full understanding of the different coating application methods, you can read about the different application methods here or give us a call, which will help you determine which method is right for you.

 

 

Important Considerations

Degree of powder coating integrity - If the underlying powder coating is missing in multiple locations and is missing significantly more than the original, it is usually best to remove all coatings from the product and start over, which usually requires sandblasting to remove the existing coating.
Extent of substrate oxidation - If the substrate has significant rust, you will most likely need to sandblast the surface rather than sand it, as you will need to remove a significant amount of the surface to provide a rust-free substrate to apply the new liquid coating. Failure to adequately prepare the surface can result in poor coating performance or even failure of the new coating.

 

Conclusion

Painting over an existing powder coating is possible and can be helpful when you need to repair a powder coated surface. By considering all of these variables, you can ensure that you are able to repair your powder coated product with a good performing spray coating.

As a Coating Line Manufacturer, LITONG has the professional training of design, manufacturing and the strength of tracking the whole process of after sale service. Welcome to contact us to learn more about the various information of color coating lines.