Ten Expert Tips for Achieving a Flawless Powder Coated Finish

Powder coating is rapidly becoming the most popular metal finishing technique for manufacturers and fab shops. It offers durability, ease of application, and an attractive appearance. Achieving a flawless powder coated finish requires attention to detail and proper technique. Whether you’re a seasoned professional with a multi-million dollar finishing line or a small shop batch coating a few parts each week, these ten expert tips will help you achieve outstanding results every time.

# 1. Surface Preparation, Surface Preparation, Surface Preparation: Bart Roegner, CEO of Reliant Finishing Systems, points out, “Over 90% of the finish defects found at most coating operations can be attributed to improper or inadequate prep work.” The foundation of a flawless powder coated finish lies in thorough surface preparation. Make sure the surface is clean, dry, and free from any contaminants such as oil, grease, or rust. Proper cleaning methods may include solvent wiping, blasting, or chemical pretreatment, depending on the condition and make-up of the substrate.

Blasting
Steam Cleaning

# 2. Mask Your Parts Properly: Nobody wants a sloppy looking finish. Before applying the powder coating, ensure that areas you don’t want to coat are properly masked. Utilize high-quality masking tapes, plugs, and caps to protect threads, holes, and other sensitive areas from powder overspray.

Masking Supplies

# 3. Choose the Right Powder: Selecting the appropriate powder coating material is crucial for achieving desired results. Consider factors such as color, texture, durability, and resistance to environmental conditions. Consult with your powder supplier to determine the best powder for your specific application. Remember that similar looking finishes can have wildly different wear characteristics, resistance to sunlight exposure, etc. Also, not all powders have the same applied cost. Cheaper powders often have more inert material, so even though they may cost less, they don’t always provide the most economical coverage.

Powders for Powder Coating

# 4. Coat in the Right Environment: Create an ideal environment for powder coating application by controlling factors such as ventilation, temperature, and humidity. Your spray booth should remove powder overspray from the work area so the operator can quickly determine coverage, but it doesn’t need to suck the powder straight into the filters. Although booths that use disposable filters are less expensive to purchase, cartridge or cyclonic exhaust systems typically have more consistent performance day after day and require much less down time for filter changes. Most powders perform best within a temperature range of 65-80°F and humidity levels below 50%. Unless you are hot flocking parts that have been pre-heated, you’ll typically get the best results in a booth that is at a comfortable temperature for the operator. Be sure to store your powder in a cool, dry place and allow it to acclimate to the shop environment before spraying. This will help reduce clumping and puffing, plus it will increase your throughput and minimize powder waste. 

Spraying 2

# 5. Assure Proper Electrostatic Application: Make sure your powder coating guns are properly adjusted for the parts you are spraying. Pay attention to your gun settings as you change from one part to another. Consistent and uniform charging of the powder particles will result in an even coating thickness and minimize defects like orange peel or blotchiness. Also make sure you have excellent grounding. This may require the addition of one or more supplemental grounding rods. We suggest 8’ copper rods connected to the part or rack by 8-gauge wire and heavy duty clamps. Parts must be well grounded to achieve optimal electrostatic application. Keep your clamps, hooks, and contact points clean and free of powder build up.

Faraday Effect
Powder Build-Up
Ground Rod

# 6. Use Consistent Application Technique: When applying powder, maintain a consistent distance and speed to achieve uniform coverage. When dealing with identical parts, determine the best way to coat the parts and use the exact same technique each time. Avoid excessive buildup in corners or along edges, as it can lead to runs or sags in the finish. Adjust your gun as needed to compensate for Faraday Cage effects.

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Spraying

# 7. Pay Attention to Curing: Follow the powder manufacturer’s recommendations for curing time and temperature to ensure proper cross-linking and adhesion of the powder coating. With some colors and powders, using a temperature that is at the high or low end of the chart may get better results, so check with your powder provider. Make sure you adjust your dwell time to compensate for the temperature and stay within recommended parameters. Deviating from these parameters can result in inadequate curing, leading to diminished durability and finish quality. It can also cause yellowing or brittleness in extreme cases of overcuring. 

Basic CMYK
Unloading Staircase

# 8. Inspect for Defects: After curing, carefully inspect the coated surface for defects such as pinholes, bubbles, blotches, insufficient coverage, or general unevenness. Address any imperfections promptly by recoating or touching up as necessary. It’s valuable to have a dry film thickness (DFT) gauge, also known as a digital coating thickness gauge, so you can accurately determine exactly how many mils of powder are on a finished part. Multiple readings from a DFT gauge, combined with cross-hatch and solvent rub testing, can help ensure that your parts have a high quality powder coated finish. 

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Basic CMYK

# 9. Be Careful With Handling and Storage: Handle coated parts with care to avoid scratching or marring the finish. Implement proper storage practices to protect against damage from environmental factors such as UV exposure, moisture, staining agents, blasting grit, or chemical exposure. One of the main reasons companies bring coating in-house rather than rely on outside contractors is to minimize the risk from handling damage.

# 10. Take Care of Your Equipment: Although nobody likes doing clean-up, a good maintenance routine will not only help your powder guns, spray booths, drying or curing ovens, and blasting or chemical pretreatment last longer, it will also keep the equipment turning out consistent, top quality finishes. Common mistakes include doing a poor job cleaning powder guns and hoses, not changing booth filters often enough, failing to wipe or blow down booth walls between color changes, failing to keep key parts like fans and bearings clean and properly lubricated, not keeping your compressed air supply cool, dry, and free of water and oil, not checking oven burner performance until there is a failure, failing to keep chemistry properly titrated, and letting racks get so dirty with baked-on powder that they can’t be adequately grounded. A few minutes a day can help reduce downtime and improve profits.

Basic CMYK
Cartridge Filters
Final Filters

We believe that by following these ten expert tips, you can enhance the quality and longevity of your powder coated finishes. Whether you’re coating hand rail, alloy wheels, machine parts, household items, lawn furniture, or sophisticated industrial equipment, attention to detail and proper technique will ensure consistently excellent results.

If you’re in the market for professional powder coating or industrial painting equipment, or you’d just like to talk with an expert about your coating process, please give us a call at (256) 513-6139 and we’ll be glad to help!