Troubleshooting Common Issues with Powder Coating Equipment: Solutions and Prevention Tips

At Reliant, we don’t just manufacture powder coating equipment; we understand it as professionals who have worked in the finishing industry for years. We strive to provide our customers with critical knowledge about operating and caring for their coating equipment. This article explains how you can get maximum results from your powder coating equipment and what to look for when it is not performing as expected.

Best Practices For Using Parts Preparation Equipment

Probably the number one cause of poor finishing results is inadequate surface preparation. Mechanical prep, like blasting, is often required if you are dealing with parts that have significant rust, grease, welding spatter, or old coatings still on them. Not only will blasting help get rid of contaminants and surface imperfections, but it can also provide a texture to the surface of the parts that will more easily accept the coating. In many cases, you may also need a chemical pretreatment process to get the best finish.

It is important to make sure you are using the right blasting media for the job at hand. Also, if your shop reclaims spent blasting media, reusing blasting material that has already seen lots of use can cause poor results because the media has been degraded to the point that it is less effective. Follow the guidelines provided by your blast media provider. 


You also need to be sure you have an adequate compressed air supply. Particularly in shops that use older piston type compressors (as opposed to rotary screw compressors), there can be performance issues where the blasting rig “runs out of steam” while blasting large parts. The ability of the blasting equipment to thoroughly strip away surface contamination is compromised as the air supply decreases because the compressor can’t keep up with the demand from the blaster. 

A related problem is caused by compressed air systems that allow excessive moisture or oil to contact the blast media or the parts. This usually happens because there isn’t appropriate filtration and moisture removal equipment installed. Problems with your powder application guns can also occur if the air isn’t cool, clean, and dry. When it comes to ensuring your equipment produces the best results, nothing beats a well-made rotary screw compressor mated to a refrigerated air dryer with a good set of filters.

From a maintenance standpoint, you’ll get your best results if your blast nozzle is in good shape. Routinely inspect the blast nozzle to assure it is clean, isn’t deformed, and doesn’t have signs of excessive wear. Using an inexpensive digital caliper to check the nozzle occasionally can help assure your blasting equipment’s performance isn’t compromised by a common wear part.

With chemical pretreatment processes, whether you’re using a simple hand sprayer, a powered spray wand system, or a multi-stage automated parts washer, it is important to keep your chemistry properly titrated. You’ll also want to avoid getting dirt or other contaminants in the chemistry. Pretreatment chemistries that are mixed too “hot” can cause problems, and trying to stretch out chemistry that doesn’t have the proper titration or is heavily contaminated can also cause poor pretreatment results. 

wash enclosure

If your pretreatment system has replaceable filters, keep them well-maintained and replace them before they cause performance issues. Check screens, wands, and nozzles routinely to maintain good working order. With older automated wash systems, nozzles that are either not working, clogged and spraying erratically, or out of adjustment and spraying in the wrong area or with the wrong spray pattern can reduce the system’s effectiveness. A small amount of maintenance can instantly improve pretreatment results. 

Get The Most From Powder Coating Guns & Powder Coating Spray Booths

One of the most common problems coaters have is poor transfer efficiency when they are spraying powder. Not all powder coatings offer the same coverage per pound. Cheaper powders often have more inert material, so even if you do everything right, you can still have an excessive amount of powder on the floor or contaminating your filters. Buy the best quality powder your budget allows.

Poor powder storage practices also cause problems. Many small shops store their powder near their coating line. Particularly in warm, humid areas, this can cause the powder to clump together and spray poorly. The powder cloud from the gun will be inconsistent, and the gun may “puff” and blow an excessive amount of powder out for a moment, usually followed by a brief period where very little powder is discharged. 

By keeping the powder in a cool, dry storage area until it is ready to be used, you’ll get better performance from your spraying equipment. For best results, you should move the powder to the coating area for a few hours before you are ready to use it so it can acclimate to the shop environment. 

Another common problem is a poor ground. You can dramatically improve how well your powder is attracted to the parts you are powder coating by assuring you have a good ground. Make sure you have a good ground at the booth. Savvy coaters will use one or more 8’ copper grounding rods installed at the booth location. They will use heavy gauge grounding straps connected to the grounding rods—think jumper cables, not speaker wire. They attach the ground straps to their conveyor, parts carts, or directly to the parts using heavy-duty clamps. This can resolve many issues related to powder waste due to poor electrostatic performance. 

coating examples

Whether you use a burn-off oven, a chemical stripper, or blast your hooks, keep them clean. Rust and baked-on powder can reduce your ground. You can still waste powder even if you use good powder and have an otherwise effective grounding system.

With powder coating booths, a common issue is poor maintenance. You must regularly clean inside the booth to get rid of dirt, debris, and spent powder. If you operate in a facility where ventilation comes from wall-mounted fans or roll-up shop doors, it is easy to get airborne contaminants like dust and pollen in the finish, especially if you aren’t careful about keeping your booth clean. 

Another area where powder coaters tend to cut corners is filter maintenance. As booth exhaust filters fill with powder overspray and airborne contaminants, they become more resistant to airflow. This increases the load on the exhaust fan drive, which can contribute to premature failure. More importantly, the booth performance decreases, and powder overspray drifts onto the floor, against the booth walls and ceiling, or travels outside the booth enclosure into the rest of the shop. 


The same thing applies to filtration for incoming air. If your booth has filtered doors or intake filters mounted in the walls or ceiling, it is equally important to make sure they are relatively clean and uncompromised. Whatever you do, don’t remove clogged booth filters and operate the booth without them. This will decrease your finish quality and can damage your equipment. 

Booth filters are meant to be serviced once they are dirty or damaged. Some filters are designed to be discarded and replaced. Others, such as cartridge-type filters, can be cleaned by agitation or by using pulses of compressed air to dislodge built-up powder and dust. If your booth has a self-cleaning feature for your exhaust filtration, ensure it operates properly.

Don’t Ignore Your Powder Curing Oven

No powder curing oven is perfect, but most brand-name ovens can produce professional-quality finishes day-in and day-out if they are properly maintained and operated. Oven maintenance practices impact oven performance and can also mean the difference between running a safe powder coating operation and putting your personnel and facility at risk. If you have safety devices that cause the oven to shut down regularly, get to the source of the problem. Don’t just reset the safety device and get back to work. No matter what, DO NOT jump out safety devices on your oven.

Ovens have safeties that interrupt operation if there is an airflow problem with the burner or the exhaust, the gas pressure is too high or too low, the oven is not igniting properly, or the burner is discharging air that is too hot. Ignoring these problems can lead to catastrophic results. Sometimes the problem is simply an adjustment issue. It can also be due to component failure or a change in the fuel or electrical supply to the oven. Reliant Finishing Systems and other reputable finishing equipment companies have technicians who can help you address oven problems before they become more serious—use them!

Gas Train

In addition to basic maintenance procedures like keeping the oven interior clean, adjusting door latches as needed, cleaning intake screens on burner air supply fans, and checking fan belts for excessive wear, you can assure your oven is performing at its best by keeping a detailed oven log. By tracking things like maintenance issues, load density, cycle times, fuel usage, and finish anomalies, you can better understand how to get the most from your oven and avoid unexpected downtime. It’s also a good idea to run a data logger every few weeks to confirm the oven’s performance and adjust for unexpected changes.

powder coating log book

In facilities where parts are manually prepped, coated, and cured in batches, improper “style of use” is probably the biggest issue that prevents top-tier results from batch powder coating equipment. The source of most style of use problems is the desire to go faster than is prudent. Trying to exceed the throughput capabilities of the coating equipment often causes more problems than any single equipment-related issue. This is particularly true of the powder curing process. 

Typical mistakes include overloading or improperly loading the oven, which changes its performance characteristics. Most ovens cure parts via forced convection heating. There is usually an area in the middle of the oven enclosure where parts are most effectively cured. In this zone, there is plenty of room for evenly heated air to travel across the surface of the coated parts.

Ovens that have powerful recirculation fans can actually blow powder off the parts if they’re placed too close to discharge ducts. Blocking wall or ceiling ducts by jamming parts in against them can also retard airflow, reducing oven performance. This can cause the oven to shut down due to inadequate airflow or excessive discharge air temps. Similarly, blocking the vent for the exhaust can cause issues, especially with airflow safety switches. 

It’s normal for ovens to have areas where the oven is hotter or colder than in the rest of the oven interior. It’s not unusual to see issues where parts don’t reach curing temperatures or don’t maintain the curing temp long enough for complete powder curing because the parts have been crammed in next to the ceiling, the floor, or right against the doors of the oven.

spiral coated staircase

If you want to get consistent results, don’t overload the oven and allow enough time to get a good cure. Some finish problems are the result of under-curing the powder by not giving the parts enough dwell time in the oven (usually because the operator is trying to get work done too quickly). Adding a few minutes to the process is much less expensive than dealing with reworking parts that don’t meet quality standards. 

A different problem can occur if the operator is running the oven at higher than normal temps to rush a job through. White powder can become discolored as a result of high oven temperatures, especially at longer dwell times. Parts coated using colored powders, particularly those that yield a high gloss finish, may have finish inconsistencies from one part to another if some of the parts are cured at a moderate temperature and dwell time and others are cured at a high temperature and shorter dwell time. 

As a general rule, the hotter you run your oven, the more stress you put on costly components like fans and burners. A practice that can shorten component life and cause finish issues is opening and closing the doors of a batch oven while the oven is loaded and in operation. In addition to safety concerns, this increases stress on the appliance and can allow contaminants to enter the oven and settle on the finish before it hardens. As hot air leaves the oven and the temperature drops abruptly, the heat system responds by increasing the output from the oven burner. This wastes fuel and can even cause finish inconsistencies if the hot parts cool rapidly and are quickly reheated. Learn the performance characteristics of your oven and allow enough time to get the job done right. 

Respect The Cool-Down

In busy production environments, batch oven operators pull parts racks from the oven and hand them off so the parts can cool down and get unloaded. The importance of this last phase of the curing process is often overlooked. Exposing hot parts to a dirty shop atmosphere or using dust-crusted fans to cool them can cause contamination. Until the powder cools fully, the finish can be soft and tacky enough to trap airborne particles of dust, dirt, and pollen that settle on the parts. Careless handling can cause contamination issues and visible damage to the finish if it has not been allowed to cool adequately. This can be prevented with proper handling practices.

In summary, implementing best practices for using parts preparation equipment, powder application equipment, and powder curing equipment is essential for achieving high-quality finishing results. Proper surface preparation through techniques like abrasive blasting and chemical pretreatment ensures the removal of contaminants and creates an ideal surface for coating adhesion. Maintaining the right blasting media, assuring an adequate compressed air supply, and regularly inspecting and cleaning blasting equipment components is crucial for optimal performance.

When powder coating, using high-quality powders, proper storage practices, and maintaining a good ground are key factors in maximizing transfer efficiency. Regular maintenance and cleaning of powder coating guns, spray booths, and filters are necessary to maintain effective performance and prevent contamination.

Additionally, properly maintaining and operating powder curing ovens and taking care of the cool-down phase contribute to safe and consistent curing results. Following these best practices can help you enhance your finishing processes, improve coating efficiency, and achieve superior finishes.