Guide to Powder Coating Finishes

Benefits of Powder Coating

Powder coating is the dry process of applying a colored powder, typically for fabricated and metal products. This dry powder method has become the preferred way to coat products instead of wet spray painting.

Powder coating works through electrostatic spray deposition (ESD). The spray gun uses an electrostatic charge to help the powder bond to the material. Once the product is coated, it’s moved to a high-temperature curing oven, which lets the powder dry and harden into a durable protective outer layer.

Powder coating is an excellent way to make a product more durable and enhance the material’s appearance. Like paint, you can choose from various colors and finishes of powder coating, including satin, metallic, gloss, clear and more. Below, you’ll learn more about the different types of powder coatings and the benefits of using this material in metal fabrication.

Types of Powder Coatings

1. Thermoplastic Powder Coatings

Thermoplastic powder coatings are a popular option, offering many benefits for different applications. These powder coatings maintain their composition when they cool and solidify and can also melt after curing if exposed to enough heat.

These powder coatings are usually applied to a surface heated beyond the powder coating’s melting point, allowing them to bond and create a smooth surface. Of the many different types of thermoplastics, nylon is the most common, but you can also find fluorocarbon-based and vinyl-based thermoplastic powder coatings.

2. Epoxy Powder Coatings

Epoxies were some of the first powder coatings, boasting durability, corrosion or chemical resistance and strong hardness. This powder uses different types of resins and is easy to use with various curing schedules. Epoxies are also one of the best powder coatings for metal since they adhere well.

While epoxy powder coatings have plenty of benefits, it’s important to note that they don’t weather like some other types. Exterior exposure can cause epoxy powder coatings to fade and could degrade after just a few months of UV light exposure. As a result, this type of powder coating is best suited to indoor applications.

Many primers are epoxies due to their corrosion resistance and adhesion strength. Since epoxies are vulnerable to the sun, they can be used as a pre-coat underneath the paint, utilizing their power while protecting against their weaknesses.

3. Polyester Powder Coating

Polyester powder coatings are some of the most commonly used powders today, offering excellent value. Two types of polyester powder coatings include:

• Tri Glycidyl Isocyanurate (TGIC)
• Non-TGICs

Both powders offer excellent mechanical resistance, including impact resistance. Polyester powders also offer quality chemical resistance. One of the main benefits of this powder type is its low cure temperature, making it a suitable choice for sensitive materials. The polyester powder is also fairly UV resistant, making it ideal for all interior and some exterior projects. You can also choose super-durable polyester if you need improved durability and wearability.

The main difference between TGICs and non-TGICs is that the latter offers all the same benefits as TGICs without the TGIC. They also provide higher first-pass efficiency but provide less overbake resistance and are more sensitive to excess film thickness.

Powder Coating Advantages

Powder coating is becoming a popular option for metal finishing at the end of the fabrication process. There are some distinct advantages when looking at powder coating vs painting methods:

• Durability: Powder coating produces a durable, long-lasting product. This process can help prevent abrasions, corrosion, fading, scratch, chipping and general wear and tear. The correct power coating material can also withstand hundreds of hours of salt spray contact, and color remains vibrant in harsh conditions.
• Uniformity: Products treated with powder coating have a smooth and uniform appearance. That’s nearly impossible with conventional painting unless applied by a professional painter working in a sterile environment. With powder coating, there are no runs, streaks or weak spots. There are no imperfections like bubbles, dust bumps or caught insects. Every surface of a powder coated product comes out smooth and perfect to the eye.
• Economy: Another main benefit of powder coating compared to alternatives is economy. Most powder coating jobs take less time than painting or plating. That results in fewer labor costs, and savings get passed on to the user. It also allows powder coating processers more profits in their work. Again, powder coating is a win-win for both customer and fabricator.
• Specialty coatings: You can apply powder coatings to various materials in different colors, thicknesses, textures and finishes, which you can’t do with other coating options. You can also choose from multiple decorative or protective characteristics to create the ideal final product.
• Reduced environmental impact: Powder coatings are more environmentally friendly than other options. For example, powder coatings don’t require solvents to maintain the coating suspension like liquid coatings, which are detrimental to the environment. Powder coatings don’t need hazardous waste disposal, don’t require a primer before application and produce fewer carbon emissions.
• Shorter curing and drying process: Powder coatings have a faster curing and drying time than other coating methods. Depending on the application, some powder coatings can cure and dry in as little as 10 minutes, while liquid coatings could require several hours.
• More material utilization: Powder coating processes use nearly all of the material. Some types of overspray powder coating can be reclaimed and reused for additional applications, which you can’t do with liquid coatings.

Choosing a Coating Service Provider

If you’re looking to choose a coating service provider, there are some tips and considerations to factor into your decision:

• Know your wants and needs: Before you choose a service provider, consider what functions the finished product should have since coatings serve different functions. Determine your budget to know what services and materials you can afford.
• Check for ISO certification: Look for service providers with an International Standards Organization (ISO) certification, an organization that requires organized and standardized coating procedures. Finding an ISO-certified provider ensures you receive quality services. You also want to choose a provider with highly skilled personnel, attentive customer service and a warranty or quality guarantee.
• Look for variety: Look for providers offering plenty of options and coating materials, including different colors and finishes.
• Consider their technology: Providers that use updated technology and facilities are often prepared to deliver more quality products with quicker turnaround times.
• Be aware of environmental factors: Some coatings can be hazardous to the environment due to the materials and chemicals used during the process. Ensure the coating service you choose has the proper equipment and facilities to protect the environment.