Powder coating serves as a durable, environmentally friendly alternative to liquid paints for those seeking other finishing options. When applied correctly, it has a long lifespan and can withstand numerous conditions without chipping or peeling. However, this phenomenon does sometimes occur, which may raise the question — what causes a powder coat to flake off? And if you see this happening on one of your parts, can your powder coating be repaired?
Fortunately, the answers to both of these questions are straightforward and easy. In this guide, we’ll explore some of the most common causes of flaking powder coatings, and discover how these issues can be repaired while maintaining the substrate’s integrity.
What Causes Powder Coatings to Flake Off?
Powder coating can flake off for numerous reasons. Here’s a closer look at how and why certain conditions and processes can cause flaking paint:
- Under curing: Under curing happens when the substrate is baked at an incorrect temperature — or it doesn’t stay in the oven for long enough. Although it may look fine when it’s taken out, the coating likely won’t have adhered to the part as it should. That issue results in a powder coating that peels, chips or flakes off more quickly than one with proper adhesion. Other signs of this include a dull finish or color degradation.
- Rough surface: The part’s surface may be rough or uneven due to sharp parts, rust or dirt. If you coat a metal part without first addressing these issues, the paint will appear uneven, and this may leave the substrate more vulnerable to corrosion. Sharp edges require proper grinding down to get the best results from powder coating.
- Lack of pretreatment: Similar to the issues associated with a rough surface, a lack of adequate pretreatment can affect the adhesion between the powder and substrate. If a part has grease, sealants, existing paint or other substances on it, it lacks a smooth surface for the powder to cling to. Some pretreatment problems can arise from the accumulation of sediment in the treatment rinse or a combination of chemicals that aren’t used correctly.
- Powder quality: Don’t forget the powder itself — its composition matters too. It may consist of too many filler materials that affect its adhesive qualities, or its primary ingredients may be of inferior quality. If either of these issues is true, you’ll need a completely new powder for the application to work.
Can a Powder Coating Be Repaired?
Can powder coatings be touched up? The answer depends on what stage of the process you’re in and the size of the affected area. If you have a finished part with peeling only in a small spot, it’s not advisable to go back over it again with powder. You’d likely need to re-coat the entire component — otherwise, you’ll leave a visible parting line between the original part and the section you’ve touched up.
Small touch-ups may be possible by mixing the powder with a clear lacquer or using liquid paint — either aerosol or a two-component polyurethane type. Keep in mind that a line of demarcation will likely be visible, and that particular section will not have the same durability as before. It may also peel or rust more quickly than the rest of the part, which will leave an uneven finish.
The best time to repair a powder coating is before the curing stage, while the material is loose. However, this can still be accomplished afterward with the right tools. You can repaint a substrate soon after curing if no contamination has affected the surface. If you choose this technique, abrasion and cleaning may be necessary before repainting. Sanding and buffing are two more effective alternatives for just-painted parts.
If the damage is extensive, though, it’s best to go with complete stripping and repainting of the part. This option is preferable for high-performance components that will see a lot of wear and tear. However, you might also make this choice for non-essential parts if you want to ensure complete customer satisfaction with a finished product.
How Long Should a Powder Coating Last?
How durable is a powder coating? It generally has a longer lifespan than liquid paints because of the way it’s applied.
Painting professionals use electrostatic sprayers to apply the substance to a substrate’s surface. The spray gun contains an electrode that creates an electrostatic field between the electrode and the product, causing the powder particles to be attracted to the part. Curing the component in the oven encourages the particles to bond and form a uniform coating.
Unlike liquid paints, there is no waiting period for the product to dry, and the coating will fully harden within a few days after curing. Powder coating will last for several years, depending on how effective your pretreatment strategy is — along with other variables characteristic to the process. Though different kinds of powder coatings exist, you can be sure you’ll receive similar levels of quality and durability with:
Choosing a Powder Coating Company With Experience
By employing skilled professionals to do the job, you don’t have to worry about the durability of your powder coating. You can be confident it’ll last you and your clients for many more years, upholding an attractive finish and sound quality. At APX York Sheet Metal, we perform the process by thoroughly cleaning the part — stripping it to its bare metals — and baking it at 400 degrees Fahrenheit.
Our powder coating solutions are developed with our clients in mind, ensuring the product is free of flaking, fading, peeling or other damages. Choosing this method over matte or gloss finishing means your product will be less vulnerable to imperfections — no repairs necessary.
Contact the Powder Coating Professionals at APX York Sheet Metal
If you need to re-apply a powder coating to a part — or powder coat it for the first time — APX York Sheet Metal is the place to go. No matter what colors you’d like to use, we can apply those hues and even create shades in-between. Our powder coating technology includes a Nordson Powder Coat Booth and a main and auxiliary oven, along with a three-stage phosphate wash system. High-quality coatings require tools of the same integrity.
If you need custom metal fabrication completed, we can also handle this process and apply a powder coating to the finished part. We’re your one-stop-shop for all your sheet metal fabrication needs — we do everything in-house for higher efficiency and speed. With over 71 years in the industry, we know what it takes to satisfy customers and produce high-quality, long-lasting parts.
Contact us today to request a free quote for your powder coating needs.