Powder coating is one of the most commonly used protective finishes for metals and various other materials. A protective finish is a very important consideration especially for laser cutting and/or waterjet cutting projects. This is because it can grant protection from harsh chemicals and the elements. It can also increase the durability and longevity of a part. Powder coating is much more durable than paint and thus, it can help prevent corrosion, nicks, and scratches.
A Memo: How Does Powder Coating Work?
Powder Coating is a process in which a dry thermoplastic or thermoset powder is applied to a surface, melted, hardened, and cured. The result is an even protective coating on the surface. This finishing process is commonly used for metals, and at SendCutSend we currently only powder coat metals, but can also be used on plastics, MDF (Medium Density FiberBoard), and glass.
Powder coating can be understood by the following basic steps:
Blasting (usually sandblasting) is often used to remove old powder coating. Before powder coating a surface, it is necessary to clean the surface from old coating, grime and dirt. Sandblasting makes use of an air compressor to propel blast abrasive grains through a nozzle at high velocity onto your chosen project surface. It smoothes and cleans the surface so that no contaminants affect the adhesion and finish of the final coating.
After blasting, further cleaning and rinsing might be needed to remove remaining particles. After final cleaning, the part is dried to prevent rusting and avoid moisture. Pretreatment can also include treating the workpiece with chemical compounds that can enhance the coating’s performance, durability, and corrosion resistance.
Primers also help prevent corrosion from creeping underneath the powder coating. They also enable the application of powders to be more consistent, and more easily bond to metal edges.
Two main methods of coating exist: Electrostatic Deposition (ESD) and fluidized bed powder coating. In ESD, powder coating is applied using an electrostatic spray gun. Colored powders are positively charged and adhere to the product. The product is grounded so that it is negatively charged. This process provides a durable and colorful finish. At SendCutSend, we do ESD powder coating. In fluidized bed powder coating, the part is heated and then dipped into a powder bath in which melted particles form a fused film on the metal part.
The surface with the powder coating is then cured in an oven or using an infrared heater. The heat causes the powder to melt and flow into a continuous film, which bonds to the metal surface. The curing process also allows the powder to crosslink and harden, resulting in a durable and tough coating.
Powder Coating Finishes
Powder coating comes in a wide range of colors, finishes and textures. Virtually any color is possible, and the coating can be used for decorative or protective purposes. Some examples of finishes include glossy, metallic, and clear. Texturing includes (but is not limited to) wrinkle and hammertone. Currently, we offer powder coating services in Matte Black, Gloss Black, Wrinkle Black, Gloss White, Gloss Red, Gloss Yellow, and Emerald Green.
Advantages of Powder Coating: Comparing Outsourcing vs. DIY
For DIY enthusiasts, there is good news – powder coating can be done at home. Home use kits exist on the market and are commonly used. However, there are pros and cons to DIY powder coating as opposed to outsourcing the powder coating.
Outsourcing the Powder Coating
The benefits of outsourcing powder coating include access to professional expertise and specialized equipment, to greatly increase the chances of consistent and high-quality results. Outsourcing saves time and resources, especially for large-scale or complex projects, while also providing the convenience of quicker turnaround times. Additionally outsourcing can offer more services, warranties, and access to a broader range of coatings and finishes. SendCutSend is a great example of a provider that could tackle outsourced powder coating projects. You can order custom metal parts and have them powder coated with a variety of colors and finishes.
DIY Powder Coating
The benefits of DIY powder coating include cost-effectiveness for small to medium-sized projects, complete control over the process and customization options, and the convenience of working on your own schedule. However, DIY powder coating requires an investment in equipment, has a learning curve for achieving professional results, and may have longer turnaround times compared to outsourcing. Additionally, complex or large-scale projects may be challenging to handle on your own. For these reasons, generally the limitations outweigh the benefits of DIY powder coating.
Powder Coating Material Considerations: How Different Materials are Affected
As mentioned before, powder coating can be done with either thermoset or thermoplastic powders. They are applied similarly, but experience curing differently. Therefore, it is important to understand the differences between these two methods, in order to make sure the correct method is being used for your intended applications. Here is a summary of the differences and unique characteristics of each.
Thermoset powder coatings undergo a chemical crosslinking process during curing. When heated, they chemically react and form a durable, irreversible network that provides excellent adhesion, hardness, and chemical resistance. Thermoplastic powder coatings, on the other hand, do not undergo a chemical change during curing. They soften and melt when heated, allowing them to flow and adhere to the substrate, but they are not chemically crosslinked like thermosets.
Thermoplastic powder coatings have the unique property of being reversible. This means that they can be reheated and re-melted multiple times without significant degradation. This characteristic allows for rework and repair of the coating if necessary. In contrast, once thermoset powder coatings are cured and crosslinked, they cannot be melted or reworked without damaging the coating.
Thermoset powder coatings form a rigid and continuous film after curing. This film provides excellent durability and resistance to mar, abrasion, and chemicals. Thermoplastic powder coatings, while also forming a continuous film, have a softer and more flexible nature compared to thermosets. This flexibility can be advantageous in applications that require some degree of flexibility or impact resistance.
Thermoset powder coatings typically require higher curing temperatures, typically ranging from 150°C to 220°C (300°F to 430°F), to achieve full crosslinking. Thermoplastic powder coatings have lower application and curing temperatures, typically ranging from 110°C to 180°C (230°F to 356°F), which can be advantageous for heat-sensitive substrates or energy-efficient curing processes.
Thermoplastic powder coatings can be repaired easily by reheating and reflowing the coating. This property allows for localized touch-ups or repair of damaged areas. Thermoset powder coatings are not easily repairable, and typically require complete stripping and recoating if repairs are needed.
When it comes to the surface being powder coated (substrate), they usually are a metal surface, such as steel, stainless steel, and aluminum. However, you can also powder coat non-metal substrates, such as glass, wood, or medium density fiberboard (MDF). In general, the substrate materials are limited to what can withstand the temperatures required to melt and cure the coating powder.
The substrate will also determine the coating method employed. For example, since metals can be electrically grounded, the coating material is generally applied using the electrostatic spray deposition method, but they can also be applied via the fluidized bed method. In contrast, non-metals require that the powder coatings be applied through the fluidized bed powder coating method.
How Long Does Powder Coating Last?
The lifespan of powder coating can vary depending on several factors, including the quality of the coating, the type of substrate, the environmental conditions, and the level of maintenance. In general, powder coating is known for its durability and longevity compared to other coating methods. It can typically last anywhere from 10 to 30 years or more.
When applied properly and maintained correctly, powder coating can withstand harsh weather conditions, UV exposure, chemicals, and abrasion. It offers excellent resistance to chipping, cracking, peeling, and fading. However, certain factors such as extreme temperatures, corrosive environments, or physical damage can affect the lifespan of the coating.
To maximize the lifespan of powder coating, it’s important to follow proper cleaning and maintenance practices. Regularly cleaning the coated surface with mild soap and water, avoiding harsh chemicals or abrasive cleaners, and promptly addressing any damage or defects can help prolong the life of the coating.
Powder Coating Done Right with SendCutSend
SendCutSend offers bold and long-lasting powder coated finishes to cut parts. Our powder coating services give your laser and waterjet cut parts a protective layer which provides corrosion, oxidation, and damage resistance. SendCutSend stands out by starting from $9, no minimum quantity. You can order anywhere from one part to thousands.We also offer discounts when you order in bulk.Enjoy the options of multiple finishes including matte, gloss, and wrinkle in several colors. Before uploading your design, check out our powder coating guidelines and read our tips for preparing your file for powder coating.
FAQs Around Powder Coating
The main difference between paint and powder coating lies in their application and curing processes. Paint is a liquid coating that is applied using brushes, rollers, or spray guns and requires a solvent or water carrier to evaporate during drying. Powder coating, on the other hand, is a dry powder that is electrostatically sprayed onto the surface and then cured through a heat process, where the powder particles melt and fuse to form a durable, protective coating.
Powder coating offers superior durability, impact resistance, and environmental advantages compared to liquid paint.