FAQ

In the field of modern manufacturing and surface treatment, the debate between powder coatings and paints is a classic one. Powder coatings, with their high durability, environmental friendliness, and uniform coating, have become a staple in automobiles, home appliances, and industrial equipment; while paints, due to their strong color flexibility and adaptability to complex shapes, still dominate in many industries. Next, we will analyze the advantages and disadvantages of both from four dimensions—principle, performance, cost, and environmental protection—combining actual test data and case studies to help you choose the right solution for your project.

1. Powder Coatings

Powder coating is an advanced dry coating technology—it relies on electrostatic spraying to uniformly adsorb powder onto the surface of conductive materials such as metals, and then high-temperature curing to form a dense protective film. Compared to traditional liquid coatings, it contains no solvents, making it environmentally friendly and providing superior wear resistance and corrosion resistance. The core of this process is electrostatic spraying and high-temperature curing, which directly determine the uniformity, adhesion, and physical properties of the coating. I have conducted tests on home appliance production lines: the material absorption rate of powder coatings exceeds 90%, far exceeding the 60%-70% of liquid coatings. This not only reduces costs but also ensures more stable surface quality. Powder coatings on the market are mainly divided into three categories, each with different applicable scenarios and characteristics:

1. 1 Epoxy Powder Coatings

They are known for their excellent chemical corrosion resistance and adhesion, and are often used to protect laboratory equipment, chemical pipelines, and electrical appliance housings. When working on a project for a laboratory equipment manufacturer, I specifically conducted acid and alkali tests: in an environment with a pH value of 1-14. the coating showed no signs of corrosion, demonstrating extremely strong stability. Advantages: Outstanding acid and alkali resistance, resistant to various solvents; tight adhesion to metal surfaces, extending coating life; high hardness, meeting the ASTM D2794 impact test standard, and will not peel off under impacts of 40-160 inches-pounds. Limitations: Not resistant to ultraviolet rays; prolonged exposure to sunlight will cause chalking, fading, and cracking, making it unsuitable for outdoor use; at temperatures below -20℃ or above 150℃, it may become brittle or soften, affecting stability.

1.2. Polyester / TGIC Powder Coating

This is currently the most widely used powder coating on the market, especially suitable for outdoor facilities and industrial equipment. Its core advantage is UV resistance, maintaining color stability over a long period. I participated in a solar photovoltaic bracket project where it was used as a coating and underwent a 5000-hour accelerated UV aging test: the color difference value ΔE < 1.5. more than three times the weather resistance of ordinary liquid coatings (ΔE > 5). Advantages: Strong UV resistance, suitable for outdoor applications such as streetlights, guardrails, and traffic signs; resistant to temperature changes, humidity, and acid rain; tested in coastal areas using ISO9227 salt spray testing, showing no corrosion for 2000 hours; rich colors, capable of producing high-gloss, matte, and metallic effects; widely used in the construction industry. Limitations: Weaker chemical resistance than epoxy resin, unsuitable for long-term contact with strong acids and alkalis; low mechanical strength, easily worn in high-friction environments, more susceptible to physical damage than epoxy coatings.

1.3. Fluorocarbon Resin Powder Coating

It is one of the most advanced powder coatings currently available, primarily used in high-end applications—architectural curtain walls, aerospace equipment, and precision industrial instruments. Its most prominent advantage is its weather resistance, maintaining long-term stability even in extreme environments. I once followed up on a commercial building curtain wall project: after using fluorocarbon powder coating, it only faded by 5% after 10 years of outdoor exposure, while ordinary polyester powder coatings faded by 15%-20%. Advantages: Top-notch weather resistance, stable in extreme temperatures from -50℃ to 250℃; passes ASTM D4214 chalking test, with a chalking grade <1.0 after 10 years (ordinary polyester coating >3.0), and no significant discoloration after 30 years; extremely low surface friction coefficient, not easily stained, reducing cleaning and maintenance costs by 40%, making it very suitable for high-end curtain walls. Limitations: High cost, 3-5 times that of ordinary polyester powder coatings; strict application requirements, curing temperature must be precisely controlled between 220-250℃, otherwise performance will be affected.

2. Paint

Paint is a coating that uses organic solvents or water as a carrier, mixed with film-forming resins, pigments, fillers, and additives. After being applied to the surface of an object through brushing, spraying, or dipping, it either evaporates due to solvent evaporation or forms a solid film with protective, decorative, and anti-corrosion functions through chemical reactions such as oxidation and cross-linking. Its market dominance is due to its flexibility, ease of application, and wide applicability—whether it’s a complexly shaped object or a material that cannot be cured at high temperatures, paint is often an unavoidable choice. Over the years, I’ve found that understanding the composition, process, and adhesion principles of paint is crucial for optimizing coating effects, extending coating life, and reducing subsequent maintenance costs. According to data from the National Coatings Industry Association (NPCA), paint still accounts for over 60% of the global industrial coating market, with usage in the automotive, construction, shipbuilding, and furniture industries far exceeding that of powder coatings. Previously, while optimizing coating processes at a factory, I compared the film-forming efficiency of solvent-based and water-based paints: solvent-based paints dry quickly and are highly adaptable to different application environments, but have high VOC (volatile organic compound) emissions; water-based paints are more environmentally friendly, but have stricter requirements regarding temperature and humidity in the application environment—this difference directly determines their applicable scenarios. Common paints are mainly divided into three categories, each with its own focus:

2.1. Wet Spray Paint

This is currently the most mainstream industrial coating method, relying on a high-pressure spray gun to atomize liquid paint and then spray it evenly. Because of its uniform spraying and strong adaptability, it is indispensable in automobile manufacturing, furniture coating, and machinery protection. I observed on an automotive production line: wet spray paint can coat various materials such as metal, plastic, and wood, and the coating thickness (10-200μm), color, and gloss can be adjusted, satisfying needs from decorative coatings to industrial protective coatings. ASTM D823-18 spray thickness testing shows that precisely controlled wet spray coatings can have a thickness error controlled within ±5μm, ensuring product consistency. Moreover, it is compatible with automated production lines, making it highly efficient for large-scale production. Limitations: Slow drying time; solvent evaporation and paint film curing typically take 2-48 hours. Speeding up the process requires additional drying equipment or UV curing technology. For example, one furniture factory found that without drying equipment, wet-sprayed paint took 24 hours to fully dry; after adding infrared drying equipment, this was reduced to 2-3 hours. Additionally, it has high VOC emissions, releasing harmful gases such as toluene and xylene during application. Solvent-based wet-spray paints typically have a VOC content of 400-600 g/L (compared to only 50-100 g/L for water-based paints), necessitating adequate ventilation and VOC filtration equipment.

2.2 Aerosol Spray Paint (Aerosol Can Spray Paint)

This is paint packaged in an aerosol can. No additional equipment is needed; simply press the nozzle to use it. It’s suitable for small item repairs, DIY crafts, and artistic creations. Its biggest advantage is its ease of use; even non-professionals can easily operate it. I’ve tried it in model making and metal repair projects: it dries in 5-10 minutes, and the coating is relatively even; it also comes in many colors, allowing for personalized effects such as metallic, matte, and gradient colors. Limitations: Small coverage area; a 400ml can typically only cover 0.5-1㎡, and the material cost is higher than wet spray paint or roller coating. ISO6504-3 coating coverage tests show that its coverage rate is 30%-50% lower than traditional paints, making large-scale construction uneconomical. Furthermore, relying on air pressure spraying limits the angle and uniformity, easily leading to uneven thickness, bubbles, and runs—I’ve encountered this before when spraying metal parts; if the angle wasn’t right, the coating effect was much worse, making it unsuitable for high-requirement industrial scenarios.

2.3. Enamel Paint

It is known for its high gloss, high hardness, and high wear resistance, and is commonly used on metal products, appliance casings, and handicrafts. After film formation, it creates a hard surface similar to enamel, with mechanical strength and corrosion resistance far exceeding ordinary paint. I’ve tested it in a metal railing project: its abrasion resistance meets the ASTM D4060 abrasion standard, showing no significant wear after 1000-2000 cycles of friction; ASTM D1308 chemical resistance testing also shows that its resistance to acids, alkalis, and solvents is stronger than ordinary paint, making it very suitable for humid or corrosive environments. Limitations: High application requirements, slow drying, full curing typically takes 24-48 hours. One appliance factory applied ordinary enamel paint to refrigerator exteriors, requiring 36 hours to fully harden; later, they switched to a thermosetting process, shortening the time to 6-8 hours. Furthermore, the coating thickness must be strictly controlled; uneven application will result in brush marks and runs, affecting aesthetics. For high-end furniture or artwork, sanding and a second coat are often required, increasing costs and time.

3. Multi-dimensional Comparison of Powder Coating and Paint

Choosing a surface treatment process requires a comprehensive consideration of material compatibility, budget, usage environment, visual requirements, and maintenance needs. For example, powder coating is more suitable for metal parts exposed to moisture, high temperatures, and corrosion outdoors for extended periods; while paint offers greater flexibility for scenarios requiring highly customized colors and compatibility with various materials.

3.1. Consider Material Type

Both processes can be used for metal materials (aluminum alloys, steel), but powder coating offers better adhesion and protection, effectively resisting metal oxidation and corrosion. Wood and plastics are better suited to paint—paint is flexible, has good compatibility, and can adapt to the thermal expansion and contraction of these materials, preventing coating cracking and peeling. For example, painting wooden furniture better showcases the wood grain texture; painting plastic parts allows for a rich variety of colors and surface effects.

3.2. Consider Budget

Limited budget, low durability requirements? Paint is more cost-effective—it has low initial costs, requires less equipment investment, is simple to apply, and has low labor costs. However, if a project requires long-term resistance to harsh environments and you want to reduce maintenance costs and extend its lifespan, powder coating is a better choice: although the initial investment is higher, its durability is strong, saving a lot of money in the long run, making it more cost-effective.

3.3 Consider the Usage Environment

In outdoor environments with high UV radiation, high humidity, and high salinity, powder coatings have significant advantages in weather resistance and corrosion resistance, making them suitable for streetlight poles, building curtain walls, bridges, etc.; indoor environments with lower weather resistance requirements, paints, with their rich colors and surface effects, can meet decorative needs, such as interior furniture and wall coatings.

3.4 Consider Visual Needs

For highly customized colors or special textures (such as cracks, metallic gradients), paints have a greater advantage, easily realizing creative designs; powder coatings have relatively fixed color choices, but can produce a uniform and smooth surface, suitable for scenarios with high surface smoothness requirements, such as appliance casings and automotive parts.

4. The Wise Way to Choose Coating

In fact, there is no “absolutely better” coating method, only the “more suitable” choice. Powder coatings are like precise and efficient “tech athletes,” adept at handling harsh environments and meeting long-term durability requirements; paints are like flexible and versatile “all-rounders,” adaptable to complex scenarios and personalized needs. When choosing, don’t get bogged down in “either/or” dilemmas, but rather return to the project itself: What materials are used? What is the budget? In what environment will it be used? What visual effect is desired? Once these questions are clear, and the advantages and disadvantages of each are compared, the most prudent decision will naturally be made—after all, good coating always adapts the process to the needs, rather than the other way around.