10 Ways Commercial Powder Coating Can Go Wrong (and how to avoid them)

Jan 15, 2019

Commercial powder coating offers a wide variety of benefits. However, it is not a DIY-friendly process. To get just the right finish, you need the proper spray guns, fine-tuned ovens, and a controlled environment. A seamless, long-lasting powder coat also requires trained experts to be operating the equipment. If you have commercial or industrial orders that need a protective finish, find a high-quality commercial powder coating service. TLC Metal Restoration has the experience, the tools, and the technical knowledge to get your next commercial powder coating job done right. We can finish your high-volume, rapid-turnaround orders without experiencing these ten common powder coating issues.

Commercial Powder Coating Building Exterior

1. Thick layers of powder ruin the finish.

More powder coating does not equal more protection. If your parts are covered with excess powder or the layers are too thick, the finish can be ruined. Two of the most common issues are orange peel and sagging. If the weight of the powder is too much, the layer can sag just like paint. This will leave dips and ripples on the powder coated surface. Orange peel looks just like its namesake. The powder forms tiny pockmarks and an uneven texture that ruins any reflective finish.

Thick coats are usually caused by improper grounding. Powder coats are applied through electrostatic forces. But if your provider does not have the tools to consistently apply grounding, then they will have to use more powder to compensate. Not only is that more expensive, but it also will not leave you with the smooth finish you are looking for.

Professionals know how to maintain the right environment for good grounding. This includes keeping clean racks and working areas. So if you get a glance of a powder coating company’s workroom and it looks clean, you know you are dealing with experts.

2. Look out for bulky edges.

Even though powder coating is a dry application procedure, sometimes it can have the same flaws as liquid paint jobs. Excess powder can build up around the edges of your parts so it forms a bulky rim. This is called “picture framing” because it looks like a thicker frame around edges and openings. The excess material can also start to peel up and develop the dread orange peel texture that ruins a shiny finish.

If your parts have lots of edges and cutouts, make sure you go to an experienced powder coating specialist. Basic tools sometimes have flow issues that make picture framing much more likely. But dedicated specialists have the tools to fine-tune powder flow. A company like TLC Metal Restoration also has the trained professionals who know how to navigate around edges to avoid buildup. For high-volume orders, we can also build a few dedicated racks to reduce any risk of picture framing.

3. Foggy bloom can ruin your item’s sheen.

Unlike the first two common problems, bloom is not caused by application errors. It is a material issue. Cheap or low-quality resins have smoky imperfections below the surface, or “blooms,” that ruin a mirrored or metallic finish. These distortions appear sporadically, so they can mar even matte and textured surfaces.

There is an increased risk of bloom if:

  • You choose dark resin colors, especially black, or you have a dark substrate.
  • Your powder coating company only provides cheaper resins.
  • The oven’s temperature cannot be fine-tuned to heat up resins quickly. Many compounds need to be heated quickly and accurately so they do not cure improperly or for too long.
  • Shop around until you find a powder coating surface with high-quality resins and the tools to do the job properly.

4. An inconsistent powder can ruin the finish.

Consistent, thick powder coating can cause orange peel. But inconsistent powder can cause even more flaws. If the powder gun cannot handle the fineness of different powders, it can splurt excess powder onto your parts’ surfaces. A spitting gun could also be caused by buildup and poor maintenance, too much airflow, and humidity.

Professionals have clean tools and a clean work area to keep your parts’ finishes consistent. They also maintain a separate environment to control humidity and airflow. They also let you know the risks of using reclaimed powder, which can clump and fluidize poorly, instead of virgin powder.

5. Look out for the Faraday Cage effect.

Because powder coating uses electrostatic, static can get in the way of covering tight internal corners. The powder would rather stick to flat planes than tricky corners. That means you could have thick streaks, thin patches, and inconsistent buildup.

This Faraday Cage effect is common, especially with complex parts. Everything from poor grounding to fine powder can make corners hard to cover. But if you need your parts protected against the element, the corners are where you need anti-corrosion protection the most.

The best way to prevent the risk is to look for a high-quality powder coating service. Expert technique, good maintenance, and using the right powders is the only way to prevent this effect.

6. Some metals have bubbly outgassing.

Almost every substrate has tiny pockets of moisture below the surface. Even metal are not are not immune: cast aluminum and cast steel are particularly vulnerable to collecting moisture. Bare metal can release that moisture. But once your parts are sealed with a powder coating, that moisture has to fight to get out. This forms little bubbles that break through the surface of the coating. Not only does it ruin the part’s finish, but it also leaves it vulnerable to oxidation.

Professional powder coaters know when to pretreat cast metals in the oven to remove the moisture. They can detect the first traces of white rust during application and remove any damaged coating.

7. Fisheyes and craters can also pock the surface.

Your parts should not look like the surface of the moon. But applying the wrong materials, or applying the wrong combination of materials, can make the surface bubble and crater. Fisheyes are even more severe. These imperfections look like larger craters with a blemish in the center.

Fisheyes and craters are usually caused by:

  • Contamination: Oil, silicone, and water can ruin a powder coated surface during application. If the powder or the substrate is contaminated with these substances, the powder cannot adhere properly. Tools and the work area can also contaminate the parts during the process, so professional powder coating services work hard to maintain their environment. Clean guns and hoses keep contamination down.
  • Poor compatibility: If you need parts to be resurfaced, there is a greater risk of blemishes. The original coat may have silicone from an aerosol spray paint. The grinding process to remove that coating may also leave behind a pitted surface that invites craters.

Before you give your parts and projects over to a powder coating surface, ask them what their pretreatment process is for recovering older parts. If they do not have an answer, go somewhere else.

8. Bad pretreatment can make the material blush.

Sometimes, the markings and impurities on the surface of the substrate can push straight through the powder coating. Aluminum oxidation and residue can show through the surface, especially if you are using a light color for your powder coating. Blushing causes blotchy discoloration, and it is impossible to remove once it forms.

Professional powder coaters know how to prevent blushing. They pretreat the surface to remove chemical residue. They can also grind away markings and stains. Professionals can also keep the risk of oxidation at bay during the coating and curing process to remove the risk of rust-based blush.

9. Powder that does not match industry standards.

Unless you are working on a personal project, you have to follow strict industry standards. Talk to your powder coating service about the powder’s characteristics and national or international ratings you need. Experienced companies often know which ratings you need for your parts and their professional expertise is an added protection for your parts and your company. According to the AAMA, or American Architectural Manufacturers Association, you should aim for a standard of 2604 or 2605.

Even if you do not have to meet specific ratings, look beyond the color and the texture of your preferred powder coating. Different powder mixtures can withstand moisture. Specific compounds can also block UV radiation damage, minimize physical impact damage, and slow down discoloration.

10. Do not settle for an imperfect color match.

If you are restoring an automobile or motorcycle, the exact colors matter. Unlike liquid paint, powders can be perfectly formulated to match the exact shade you need. The compounds can also be mixed for just the right texture and finish. Some companies may only offer the basics or try to discourage you from getting the custom color you need.

Look for companies that take the time to help you select precisely what you are looking for. Not only do experienced powder coating specialists understand how important getting the right shade is, they know how to do it. They can color match, order powder based on color swatches, and test the powders before full application.

Never trust your inventory in the hands of a company that does not have the resources or expertise to get it right the first time. At TLC Metal Restoration, we are proud to be listed in the Blue Book and the Building & Construction Network. Contact TLC Metal if you have clients, parts, tools or equipment that need professional commercial powder coating.