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Pinholes and Outgassing: Troubleshooting Your Powder Coated Finish

Pinholes And Outgassing: Troubleshooting Your Powder Coated Finish #reliantfinishingsystems

Time and effort wasted: a cured part full of pinholes is what you want to avoid.

You’ve prepped your part, applied the powder, and now you’re waiting to pull the finished product out of the oven. Maybe it’s a piece that your customer desperately needs or maybe it’s a part you’ve taken special care to finish for yourself. But once you take it out, instead of a beautifully smooth finish, you’ve got a ragged, pitted mess – your coating is full of pinholes.

What Causes Pinholes?

Pinholes develop from a process called “outgassing.” Pinholes occur during the cure – as the part heats up, gasses that are trapped on or inside the part escape through the powder, causing holes or bubbles in the finish. These pinholes are not only unattractive, they also allow moisture and corrosion to penetrate the coating and damage the surface.

Troubleshooting Outgassing: What To Look For

Understanding how pinholes occur and where they come from is key to preventing them. We’ll go over the main three causes and how best to troubleshoot them below.

Make Sure Your Product Is Clean

Troubleshooting Powder Coating: Anything not cleaned off of the part - solvents, grease, oils and other contaminants - can cause disastrous results. #reliantfinishingsystems

Anything not cleaned off of the part – solvents, grease, oils and other contaminants – can cause disastrous results.

One of the primary causes of pinholes is surface contamination. Solvents, grease, mold release agents, and machine oil can all vaporize through the powder coated finish during the curing process. Leftover residue or improper cleaning can subject your part to a variety of finish defects, including pinholes.

Preventing this type of problem comes down to proper cleaning. Identify the contaminant(s) and remove them prior to applying powder. If the problem continues, you may have to add an additional pretreatment step to your coating process in order to achieve the level of cleanliness you need to avoid pinholes (for more information on pretreatment, read our article here).

Your Products – Or How They Were Treated – May Be To Blame

Powder Coated Cast Fitting

Pinholes can occur from the parts themselves, especially cast metal parts.

Cast metal parts made of aluminum, iron, steel, and brass are some of the most likely to have outgassing issues. With both die-cast and sand-cast parts, gasses can become trapped in the part during the pouring process. High-quality castings using premium metals will almost always have less entrapped gas.

Outgassing can also happen occur when a powder coated finish is applied to material that already has a zinc surface treatment, like galvanizing. During the galvanizing process, gasses can become trapped within the surface coating. It is the escape of these trapped gasses that can cause outgassing problems when curing galvanized steel parts that have been powder coated.

Galvanized Steel Surface Unfit For Powder Coating

Surface treatment, like galvanizing, can also cause pinholes in your powder coating.

Pre-baking the part can solve this type of issue. Pre-heat the part before coating, then allow it to return to room temperature. We recommend the product be heated to a temperature slightly above your target curing temperature and held at temperature for a little longer than the part would normally be cured. While some parts are of such poor casting quality that this method won’t work, this solution is effective for the majority of outgassing issues.

In extreme cases, it may be necessary to modify the design of the part, impregnate the casting, or use a sealant during the production to get the best powder coating results. It may also be possible to use IR curing or change the coating to one that uses a time/temperature recipe that doesn’t result in the part’s mass being heated as intensely during the curing process.

Make Sure You Aren’t Applying Too Much Powder

Powder Coating Application Using Powder Spray Gun

Good coverage techniques and quality control testing will help you avoid overloading your products with powder.

Pinholes can occur with some powder coating materials when they are applied in one heavy coat of greater than average thickness. When this happens, gasses that escape during curing are released through the outer surface of the coating after it has begun to cure, causing imperfections in the surface that remain after the part has cooled.

Check your film thickness to make sure you’re aren’t getting too much powder on your products (we discuss powder thickness in our article on quality control testing). If the part requires a coating with a particularly heavy film thickness, apply 2-3 thinner layers instead of one heavy layer.

Some companies also offer coatings with enhanced flow characteristics that enable the coatings to remain liquid for longer periods of time during the curing process. Trapped gasses can escape harmlessly when the coating is still liquid. The coating will flow into the imperfections caused by the gasses’ exit and yield a blemish-free finish. These specially formulated coatings can also be used for applications where a thinner film thickness is acceptable but the parts’ outgassing cannot be eliminated.

Get The Best Finish With Proper Equipment And Training

Reliant Finishing Systems not only offers professional-grade spray booths and curing ovens to get the absolute best results, but we also offer a wide range of troubleshooting and training services. Whether you need a new system or want to improve your existing operation, we can help. Give us a call today.

Why Powder Coating Is Good For The Environment

Powder Coated Metal One of the key advantages powder coating has over other finishing processes is how safe it is for the environment and for the people who work with it. Unlike traditional solvent-based wet paint, powder coating is considered a “green” technology that doesn’t generate harmful solvents or airborne pollutants. Compared to painting, powder coating reduces finishing line emissions, produces far less harmful waste by-product, and doesn’t pose a significant health risk to your employees or neighbors. Understanding the impact of these green benefits can help your business make the right choice when choosing a new finishing system—and help you gain support from your community.

Powder Coating Generates Negligible VOCs and No Real Air Pollution

A significant difference between industrial wet painting and powder coating is the presence of Volatile Organic Compounds, called VOCs for short. VOCs (like formaldehyde) are released into the air over time, either as the paint is cured or as it ages. VOCs damage the ozone and, if trapped indoors, can cause serious health problems to people exposed to them. Traditional liquid paint emits VOCs. Newer paint technology includes No-VOC and Low-VOC products, but these are often not capable of providing a finish that is adequately robust. By comparison, powder coated finishes are tough and durable, yet cause the emission of almost no VOCs. Powder coating media and powder coating in general is considered non-toxic, which it is why powder coating is strongly recommended if your finished product will be used or installed indoors.

Since powder coating is inert and produces almost no VOCs, applying it does not create harmful fumes or contribute to air pollution. While you will still want to spray inside a booth with a true filtered exhaust including HEPA filtration, you won’t otherwise have to duct the air from your booth to the outside atmosphere. Although powder overspray is considered a nuisance dust, properly filtered exhaust from a powder coating booth is clean enough to breathe, so you don’t have to exhaust the booth outside the shop space. This makes powder coating even more energy efficient because you won’t be wasting heated or cooled shop air by exhausting it to the outside atmosphere.

Powder Coating Produces Significantly Less Hazardous Waste Than Wet Paint

Traditional wet paint lines produce hazardous waste in two key areas: Retouching and Disposal. Because of the chemical composition of wet paint, coating defects often require costly reworks using solvents. These chemicals produce harmful fumes and the used solvents are considered hazardous waste. In addition, stripped and discarded paint may also be hazardous waste and should be disposed of properly – which can be an expensive and time-consuming process that many shops ignore.

Since powder is considered inert and does not require special handling or disposal, powder coating media is much safer to handle and isn’t hazardous to retouch. Fixing a mistake is also much easier (provided you catch it before curing). Instead of using harsh chemicals, if you find a mistake on a powder coated part, you can simply wipe the part clean or used compressed air to remove the uncured powder and reapply it. Any waste powder can be swept up and handled without special safety equipment, and it can be discarded with normal shop trash.

Powder Can Be Recycled

Powder coating is a two-stage process. First, your product is sprayed with powder using an electrostatically charged powder gun. The powder adheres to the part, but must then be cured inside a powder coating oven to melt the powder so that is flows together and locks onto the part. This process creates a strong and very durable bond that lasts and helps protect the metal underneath. (You can even increase this durability with different pretreatment methods – for more information on pretreatment, take a look at our Pretreatment Primer.) But what about the powder you spray that doesn’t adhere to the part?

The excess sprayed powder can be recycled using a process called powder reclamation. This works best when only one or two primary colors are used for your products, as multiple color changes can drive up equipment costs considerably (for more information, see our powder coating gun article here). However, if you are only using spray one or two colors most of the time, then you can see significant savings by reclaiming the powder overspray that gets trapped in the filters or falls to the floor of your spray booth. (For more information on how much powder you can reclaim to increase powder transfer efficiency, click here.)

Powder Coating Already Complies With Environmental Regulations

Because powder coating is considered non-toxic, is inert and produces negligible VOCs, it already meets or exceeds many national environmental protection standards. Although your shop will need to clarify with your local authorities, powder coating is considered safer and will not require the same level of oversight and waste disposal care that wet paint operations do. Also, because powder coating media doesn’t present a spill hazard, you don’t to invest in a paint mix room or storage room.  As long as the powder coating equipment you purchase meets national safety codes, your operation will already meet or exceed national environmental regulations.

All Reliant Finishing Systems’ Equipment Is Produced To Meet Or Exceed National Codes

If you’re looking for safe and effective powder coating equipment, look no further than Reliant Finishing Systems. Our powder spray booths and powder curing ovens are designed specifically for powder coating applications and can be customized to fit your shop’s exact application. Whether you’re a finish line manager seeking a turn-key automated powder coating line, an established powder coater in the market for new equipment, or a fab shop owner wanting to get started with powder coating, Reliant can help.

Have questions? Email us or give one of our systems specialists a call today or visit our Resources page.

 

Dealing With Unhappy Powder Coating Customers

powder-caoted-part-with-coating-contamination

If your powder coating has chips, bubbles or has contamination (shown above) your customers won’t be pleased.

As a job shop owner, powder coating specialist or coating line manager, you’ve probably dealt with unhappy powder coating customers. Dissatisfied clients can have a number of complaints: some customers are sensitive to price, others may be sensitive to turn-around times or coating mil thicknesses, others may be unhappy with overall finish quality or other issues. Unfortunately, you may not know why a customer is unhappy until the very end of the project or after the order has shipped. Whether they complain face-to-face, you hear about their remarks from someone else, or you see a negative review online, a dissatisfied customer can be frustrating to you and disruptive for your business. What’s worse, if you ignore them, it’s likely that a problem customer will only get worse. Business experts agree that when it comes to dealing with mad customers, there’s only one “right” way to react: Contact them, take some kind of action to address their grievance, and most importantly, act quickly.

What angers already-irritated customers most? Being ignored or left waiting too long for a resolution to their problems. By responding to a customer’s complaints, you validate their need to be heard. Let them know your business is willing to listen. Approach your customers with genuine concern. View customer complaints as opportunities to demonstrate your shop’s commitment to customer service. A positive, friendly outlook will likely win over frustrated customers – as long as they have realistic expectations.

Reliant Finishing Systems builds and sells powder coating appliances. They deal with customers from around the world through various websites and conventional resellers. Their staff monitors digital media constantly to provide quick responses to customers who publicly voice their dissatisfaction. They also actively contact buyers within days of providing equipment so they can learn about potential problems before they get out of hand.

When dealing with their customers, powder coating shops can assure customer satisfaction by using a similar approach. Don’t use the “No News Is Good News” approach. Have an employee or third-party company proactively reach out to all of your customers to find out what they really think about their experience with your company. By documenting all of the comments–not just the good ones–you can get a better picture of what you’re doing right and where you need to improve. Some problems are truly isolated cases of miscommunication or poor performance, while others may be part of a larger issue.

One area that powder coating shops can immediately increase customer satisfaction is through improved quality control. Many of the complaints you are likely to receive will be due to a perceived lack of finish quality, whether that is poor coverage, uneven application, bubbling, or other coating issues. By adding a rigid and consistent quality control regimen to your process, you can catch many mistakes long before they reach a customer, saving you time and increasing customer satisfaction. (For more information about adding quality control to your process, check out our Introduction to Powder Coating Quality Control Testing.)

Grow Your Business With Increased Customer Satisfaction

Michael Schuerer, President of Reliant Finishing Systems, believes that attention to customer service has helped the company’s rapid growth. “It’s important to constantly listen for negative feedback and approach it rationally when you encounter it. We’ve found that it’s easy to get defensive or discount what a particular customer has to say, but that doesn’t help you grow your business or improve your brand. Sometimes you just have to pause and look at the situation with a fresh perspective. Successful companies treat their customers with respect, even when that proves challenging. Reliant wants to make sure our customers are pleased with both the equipment and the support they receive from us, so we try hard to assure that our customer service decisions are fair and thoughtful.”

Reliant recently had a frustrated customer post something negative about the company on Facebook. Within a few hours of his post, the company called to resolve the issue. That level of awareness and responsiveness can help you grow your reputation, but it takes consistent effort. It also takes patience to remember that you’re dealing with real people who can be very emotional once they’re unhappy. It may be difficult to address a customer’s complaints, but it’s worth it in the long run.

Even if your shop’s budget prevents you from hiring a PR firm or performing elaborate customer satisfaction surveys, there are three things you can do to help keep your reputation intact:

BE AWARE. Go to business expos and civic meetings that your customers attend. Listen to what’s being said. Try to interact with customers in a way that makes it easy for you to learn just how happy or unhappy they are. Set up notifications on your Facebook page and any other online outlets you use to interact with customers or sell online. Check your pages and your customers’ blogs or forum comments routinely to make sure they are happy with your company.

BE ACTIVE. Reach out to frustrated customers immediately. If nothing else, let them know you’ve received their complaint and you’re company is working to resolve it. Problems are usually much easier to work out if the customer gets a personal touch. A face-to-face meeting is better than a phone call, and a phone call is better than an email or private message.

REMAIN ENGAGED. Keep in touch with unhappy customers to resolve their issues and, when appropriate, offer compensation for their time and trouble. Sometimes a simple apology is all that is needed. At other times you may need to consider reworking bad parts or offering a discount on future orders. By staying involved with your customers, you help assure that their complaints are resolved—and that you have the opportunity to do work for them in the future.

By staying engaged with problem customers and proactively reaching out to your existing clients, you can not only help solve their issues – you can help identify areas where your company does need to get better. A company that is known for helping to solve problems, reacts positively to critique and works to actively improve their relationships is a company whose reputation will grow and whose business prospects will increase.

Beginner’s Guide To Powder Coating Equipment

powder coating applicationIf you want to powder coat but aren’t sure where to start, our Beginner’s Guide to Powder Coating Equipment is intended to help anyone learn about the business of powder coating. Whether you’re just curious about professional powder coating or ready to install your first coating line, this brief overview will give you the basic information you need to get started.

What Is Powder Coating?

Powder coating is a multi-step finishing process. In the first step, a product (usually a metal part) is cleaned and prepared for coating. Next, it is coated with a fine powder. The powder covers the part’s surface. In the final step, the part is moved into a curing oven. The product is then heated in the oven, allowing the powder to melt and flow into a uniform coating that adheres to the part. This creates a very durable and attractive coating around the product once the melted powder cools and hardens.

What Sort of Equipment Do I Need For Powder Coating?

There are three different types of powder coating equipment you must have to perform professional quality powder coating:

Pretreatment (Where Your Product Is Cleaned Prior To Powder Coating)

Application (Where The Powder Is Sprayed Onto The Product)

Curing (Where The Powder Is Cured Into A Durable Finish)

Pretreatment For Powder Coating

To achieve the best results with your powder coating process, your product needs to be clean—free of dust, debris, oil, rust, old paint or finish material. Anything left on your product prior to coating will affect the powder’s adhesion and durability. That’s where pretreatment comes in.

Pretreatment equipment is used before your product is ever powder coated and is designed to make sure that your product is as clean as possible before powder is applied. (For more information on pretreatment, start with our Pretreatment Primer.)

Operator Inside A Blast RoomIf the product you want to powder coat has a lot of debris (rust, laser scale, preexisting paint), then you will likely need a Blast Room. A blast room is an enclosure where you use compressed air to propel abrasive material against the surface of your parts. Depending on the situation, you would typically use either an appropriate blast media (grit) or steel shot to blast all the unwanted debris off your part until it has a clean metal surface that’s ready for powder coating. Blast rooms are especially useful for job shops that work with raw materials that aren’t pristine, such as plate steel or tube stock that has areas of oxidation or welding residue. (For more information on getting the right blast room, go here.)

 

pretreatment-for-powder-coating-with-manual-spray-wandIf oils, solvents or chemical residue covers any part of your products’ surface, you’ll want to consider a Wash Station. A wash station is where you spray your parts with a detergent and/or chemical pretreatment agent, such as iron phosphate. Using hot water or steam to clean and then chemically prep parts is quite common. A wash station helps you increase powder adhesion and improve finish quality, even if the parts have already been blasted. Some wash stations require you to apply the chemistry manually using a spray wand. Other washers are automated and the parts travel through the cleaning, rinsing and prep stages on a conveyor.

In some operations, pretreatment requires the use of a Dry-Off Oven. This is commonly an appliance similar to a curing oven, but where the just-washed parts are heated in order to evaporate any water or chemistry still on them. This step can also help parts reach an optimum temperature for powder application.

Pretreatment equipment is incredibly useful for your operation and can make a big difference in the quality of your work, but an elaborate system isn’t always required for powder coating. While we can’t stress how important it is to have a clean surface before you apply powder, expensive pretreatment equipment isn’t mandatory for entry level coating operations where hands-on cleaning (such as with a tack rag and solvent) can be employed as needed.

Application: Powder Guns and Powder Spray Booths

powder-coating-gun-and-controlsPowder coating application is almost always done with a special Powder Spray Gun. In order for powder coating to work effectively, the powder must be electrostatically charged. The only way to apply this charge is with a spray gun designed exclusively for powder coating. Compressed air moves powder through the gun from a hopper or directly from the box the powder is stored in. The compressed air blows powder out of the gun as a tightly formed cloud. As the powder leaves the gun, it receives an electrostatic charge. Once charged, the powder cloud envelopes the part and the powder sticks to the surface of the grounded part (which is one of the reasons why powder coating equipment is so easy for new operators to use).

If you want to powder coat, you need a powder coating gun. There are many types of powder spray guns available on the market. We always recommend investing in a professional-grade powder gun, as they are more reliable and provide better results.

Once you have your powder gun, you’ll need to have a place to use it. Whenever you spray powder, some of the powder will end up on the floor and in the air instead of on your products. This leftover powder is referred to as overspray. Keeping this overspray out of your workspace is one of the functions of the Powder Spray Booth.

powder-coating-application-inside-powder-spray-boothThe powder spray booth is designed to keep the rest of your shop clean while providing a well-lit area for you to apply powder coating. All powder spray booths will have one or more exhaust fans. The exhaust will use filters to capture at least some of the overspray. If the exhaust works properly and the filters are maintained, the airflow in the booth should keep the overspray inside the enclosure and enable the painter to see what he’s doing. If your shop environment includes welding or blasting areas, filtered doors on the spray booth can keep airborne contaminants out of your powder coated finish.

rack-and-powder-gun-in-powder-spray-boothNumerous booth configurations are available, and getting the ideal booth depends largely on what you’re coating, your floor space availability, and your workflow requirements. Powder spray booths can be open-faced or have doors on one end. They can also be tunnel style enclosures with the filtration built into the floor or wall(s). If you have space constraints, a Powder Spray Wall may help you get the airflow and filtration you need. A spray wall is just a large filtration system—essentially a spray booth without walls or a roof.

If you want to recycle your powder, you need to make sure your powder spray booth is built with a reclamation system. Usually this system will rely on pleated cartridge filters. These help you recover some of the overspray and reuse it. This can be very cost-effective if you are planning to use only one color and type of powder for your coating. The spent powder is trapped in the filters and then dislodged into a recovery bin for reuse. In more advanced systems, the powder is automatically reconditioned, mixed with virgin powder, and then returned to the supply hopper feeding the powder gun(s). If you are planning to reclaim a variety of colors, a set of removable filter modules is required. Unfortunately, the cost of buying multiple reclaim modules can add up quickly because you can only reclaim one color in each filter module.

No matter what type of booth you decide on, you’ll need a powder spray booth if you want to get quality results and maintain reasonable throughput from your coating operation. (For more information on what size powder spray booth you might need, click here.)

If you have stringent finish requirements, you may also need a Clean Room (also called an Environmental Room). This is usually a climate-controlled room built around the powder application area. The purpose of a clean room is to eliminate airborne contaminants and control the temperature and humidity during powder application to prevent any sort of contamination, clumping or consistency issues when applying the powder. Clean rooms are often recommended if your shop environment is particularly dirty or your products require an exact specification for adhesion or salt spray tolerance. (For more about requirements, click here.)

Curing: Powder Curing Ovens

Batch Powder Curing Oven - Doors OpenAfter your product is powder coated, the final step is to place it inside a specially designed Powder Curing Oven. They usually operate between 325° and 450° Fahrenheit. Once the oven is up to temperature, the temperature stabilizes. The coated products are exposed to precisely heated air for a set period of time. Once the curing process is complete, the parts are removed and allowed to cool before being handled.

Some ovens use infrared emitters to heat the surface of the coated parts, but these types of electric powered or gas catalytic ovens can be costly to buy and expensive to maintain. More commonly, ovens rely on electric heating elements or a natural gas or LP-fueled heat system. These more conventional ovens typically rely on heated air moving over the parts for convection curing.

The time it takes to cure the powder varies greatly depending on the size, shape and thickness of the parts being coated. A small, light-gauge bracket can take as little as ten minutes to cure completely, while a 20’ section of heavy-walled pipe may take over an hour to cure properly.

Powder Coated Parts After CuringIf you want to powder coat at a professional level, the type of oven you choose is critical.  Not only are brand-name powder curing ovens designed specifically to generate premium coating results, they are also highly efficient appliances in terms of fuel usage and energy costs. It’s likely that you’ll be using your oven several hours per week, so the cost of an inefficient design can quickly sap your profits.

Similar to powder spray booths, powder curing ovens come in multiple sizes and configurations. (For more information on what size powder coating oven you will need, click here.)

Professional Powder Coating Systems Layouts

There are two basic configurations for any powder coating line: batch or automated.

general use-powder coating equipment batch configurationA Batch Powder Coating Line is usually a system where the parts are prepared, coated and cured in batches of multiple parts, with operators handling up to dozens or hundreds of parts at a time. The products are usually hung on metal rolling racks, which move with the parts throughout the coating process. (Remember: high-temperature or metal casters for your racks are very important!) With a batch line, parts are usually moved from stage to stage manually, and the term “batch coating system” is also commonly used to describe operations where large objects are coated individually after being moved by hand or with machinery.

Automated Finishing SystemsAn Automated Powder Coating Line uses basically the same appliances as a batch system, but connects many or all of the stages via a motorized conveyor that moves the parts through at a constant rate. The products are usually loaded onto the conveyor at a set location and move through each stage, where either manual operators or automated devices clean and prep the parts and apply powder to them. Once coated, the parts move through the curing oven and then cool as they travel along the conveyor to a point where they can be unloaded.

(For more information on whether a batch coating line or an automated coating line is right for your business, follow this link to learn more about the advantages and disadvantages of each system.)

Powder Coating Equipment From Reliant Finishing Systems

Hopefully this Beginner’s Guide to Powder Coating Equipment has answered your basic questions about what powder coating is, how it is done, and what you need to start your first powder coating line. If you would like to learn more, please give us a call at (888) 770-0021. Reliant Finishing Systems’ specialists can help! We’ll guide you through the process of setting up a powder coating shop or adding coating capabilities to your existing fab shop or manufacturing facility. Whether it’s your very first powder coating system or you’re upgrading to a complete automated line, you can trust Reliant to provide you with sound advice and affordable, high quality equipment.

Free On-Site Powder Coating Workshop

Spend $30,000 or more on any new powder coating equipment and receive a free powder coating workshop when you purchase before December 31st, 2016!
get-smart-v2-4-final

Learn From An Industry Expert

Our Advanced Powder Coating Workshop is taught by our resident powder expert, Bruce Chirrey (who has written a host of helpful articles on powder coating, including here, here and here). Bruce’s 25 years of experience and extensive powder coating knowledge will be at your disposal for up to 12 hours of on-site, hands-on powder coating training. Bruce will cover:

  • The Basics of Powder Coating Application
  • Understanding Powder Coating Gun Settings
  • Tips & Tricks For Better Coverage
  • Advanced Coating Techniques
  • And much more!

checking-parts-for-powder-coating-consistency

Hurry! This offer is only valid until December 31st, 2016 and is valid on ANY* purchase of $30,000 or more on new capital equipment.

*Advanced Workshop offer available in the contiguous US. Not available with any other offer.

Powder coating machine installation and services

What Size Powder Spray Booth Do You Need?

(Be sure to check out our article What Size Powder Coating Oven Do You Need? for more information on matching your powder coating equipment for best results.)

powder-spray-booth-with-true-hepa-filtrationJust like with your powder curing oven, your powder spray booth needs to be large enough to accommodate either the largest product you will routinely be coating or the largest batch of products you must coat in order to meet your shop’s throughput requirements. Your booth may need to be a bit larger than your oven if you are dealing with large parts, or it may be possible to use a smaller booth if you coat multiple small racks of parts before curing them all in one large batch. Regardless of the booth’s size, you need an appliance that is large enough to hold your products and provide enough space for the operator(s) to move and work efficiently.

Although this article focuses on batch coating processes, many of the concepts also apply to powder coating in a constant-process environment where parts are moved via conveyor instead of on rolling racks or carts. With both batch and automated lines, it is not uncommon for booths to be open-faced or to have ware openings instead of doors that seal the parts inside the powder coating booth. Unlike with conventional wet paint processes, contamination by airborne dust or debris is usually less problematic when powder coating.

Prevent Powder Contamination In Your Work Environment

checking-parts-for-powder-coating-consistencyDuring powder application, the powder that does not adhere to the part is called overspray. Overspray generally falls to the ground or is moved by the booth’s airflow and pulled into the filtration system, but only if the powder is sprayed inside the booth while the exhaust is operating. Spraying powder outside the booth or away from the filters can lead to powder contamination of nearby appliances (including your curing oven). The airborne powder is a nuisance dust that can travel throughout your workspace.

When sizing your powder spray booth, make sure that the booth is large enough to completely enclose the largest product you’ll be coating. This ensures that all the powder is being sprayed inside the booth, which eliminates powder contamination of the shop environment.

Add Interior Space To Improve Efficiency

room-to-work-in-a-powder-spray-boothThe largest product you are coating should easily fit inside the booth with extra room for each operator to both move himself and the powder coating gun around the part. Adding additional space gives your operator adequate room to work without jostling or bumping the product that is being coated. Prior to curing, applied powder media is fairly easy to remove. Any accidental contact with the part will require touch-up if not a total rework.

Besides adding room for the painters, you also need to allow room for your racks. Let’s say you have a 6’ tall part and you want to coat it in an 8’ tall booth. If the rack and hook cause the part to hang about 1’ from the ceiling of the booth, the painter is going to end up having to paint a portion of the part that is only 1’ off of the floor. To do this effectively can be slow and tedious, and this type of cramped working space contributes to fatigue.

Another issue is maintenance. In the scenario above, the top surface of the part being coated is only 1’ from the ceiling. This means that the booth’s ceiling and ceiling-mounted lights will be coated with powder overspray. After an hour of painting, the lights will have a film of powder over them—reducing illumination in the booth and causing the light coming from the fixtures to be tinted by the thin layer of powder as it passes through. This makes it harder for the painter to gauge coverage. Greater contamination by overspray also translates to greater cleaning costs and more down time as the booth must be frequently cleaned with compressed air or wiped down. The same problem can occur when spraying parts that are too close to the walls. It’s easy to dislodge accumulated powder and contaminate fresh parts, especially if the old powder on the wall is a significantly different color or gloss compared to the powder being applied to the parts.

If you are going to be using a single large rack per batch, we recommend that the powder spray booth be an additional 2′ – 6′ wider than the matching powder coating oven. This gives your painters room to work. We also suggest that you consider a booth that is 2’ taller than your oven to reduce cleaning hassles associated with powder covering your light fixtures. One of Reliant Finishing Systems’ most popular batch equipment packages is sold with an 8’H x 8’W x 25’D (interior) curing oven and an 8’H x 10’W x 25’D or 10’H x 10’W x 25’D (interior) powder spray booth for this very reason.

Determining Your Powder Spray Booth’s Footprint

Make sure you have enough available floor space to put the right size booth in your facility. Note any low ceilings, structural supports, posts or columns, or other obstructions that might restrict where your powder spray booth can be installed. Carefully planning the layout of your booth, oven (https://www.reliantfinishingsystems.com/powder-coating-equipment/powder-coating-ovens/) and pretreatment appliances before you buy them can prevent headaches later.

While the overall footprint of most powder booths is similar to their listed interior dimensions, there are a couple things to keep in mind. Every powder spray booth comes with at least one integrated, attached or separate exhaust chamber that houses the filters and the exhaust fan system. Depending on the powder spray booth’s configuration, these exhaust chambers are attached to the rear of the booth or to one or both of the side walls. These exhaust chambers usually add an additional 4’ to 5’ of depth if attached to the rear, 4’ to 5’ of width if a single side wall has an exhaust, or 8’ to 10’ of additional width if both walls have exhaust units attached.

As an example, a standard model PSE81025 from Reliant Finishing Systems is a powder spray enclosure that is approximately 8’H x 10’W x 25’D inside. It comes with an exhaust chamber that is built into the rear of the booth enclosure. The overall exterior length of the booth is 28’10” including the exhaust unit.

powder-spray-booth-header-panel

The header panel adds approximately 2′ of extra height to the front of your powder spray booth.

Another space consideration is the header panel. The header panel is usually about 2’ tall and is added to the front of spray booths in order to keep airborne powder from drifting over the top of the booth and into the light fixtures. The header also assures that the light fixtures are adequately isolated from the booth interior to meet national codes, such as NFPA 33. The header panel is installed on the very front of the spray booth, above the main opening, and is typically only a couple inches deep, so you won’t have to account for its additional height over the entire appliance.

In addition to the total exterior dimensions of the powder spray booth, we suggest that you allow for at least 3’ of clearance around the booth in order to make installation and maintenance less costly and to meet common codes and regulations once the booth is installed.

Adjust Workflow With Different Booth Models

The type of powder spray booth you decide on can also greatly influence your powder coating system’s layout and workflow. Reliant Finishing Systems provides three different configurations of powder spray booths, shown below.

A STANDARD powder spray booth has an enclosed cabin with a filtered back wall. Many batch powder operations use standard booths and install them side-by-side with their powder coating oven (again, allowing for at least 3′ between appliances and the walls).

Remember: Some companies, especially those that primarily deal with wet paint booths like those used in automotive body shops, this design may be called a “crossflow” configuration to differentiate it from “downdraft” designs where the air travels from the ceiling into a metal basement or excavated pit under the booth before being exhausted.

powder-spray-booth-crossflow-configuration

Shown: a crossflow style powder spray booth. A crossflow style booth has an exhaust chamber on one side wall. A double crossflow would have an exhaust chamber on both side walls.

A CROSSFLOW powder spray booth usually does not have a back wall. Instead, it has the exhaust filters installed on one side wall. This creates a tunnel-style configuration that allows you to move whatever you are coating in one end and out the other.

A DOUBLE-CROSSFLOW powder spray booth is also tunnel-style booth. It is similar to a crossflow configuration, but has an exhaust system mounted on each side wall. One benefit of this design is that it allows the painter to stay clean and work quickly. He can move the rack slightly and always be painting into the exhaust filters—as opposed to spraying powder onto the part while the exhaust is behind him, causing the overspray to cover him as it is pulled out of the booth by the fan. A double-crossflow booth also allows two painters to work effectively at the same time, especially when the exhaust units are mounted in a diametrically-opposing position. In that configuration, each painter deals with only one part of a large part or rack full of parts and is always spraying into the exhaust filters. As the rack moves through the booth, each painter sprays only a designated portion of the parts being coated.

In nearly all types of automated systems, a tunnel-style powder spray booth is paired with a tunnel-style powder coating oven with track running through both appliances so a continual coating process can be maintained. In a batch setting, the booth configuration should help improve coating workflow and maximize use of available floor space.

Plan For Staging Areas Around Your Coating Equipment

racks-for-powder-coatingAnother thing to consider when planning for your powder spray booth (and your coating line in general) is staging. A staging area refers to the additional shop space you’ll need for storing racks and parts as they move through the pretreatment, coating and curing processes. Even if racks are only going to be parked in a spot for a few minutes, it is important that the spot is clearly defined and kept clean.

Make sure you have a staging area where the parts can be prepared before they enter the powder spray booth. Whether you use blasting, chemical pretreatment, or simply a wipe-down before the parts are coated, you need to be able to stage parts after they’ve been prepped. This staging area is where your racks will be loaded with clean products, and may be where empty racks are returned. This staging area needs to be large enough to accommodate at least one typical batch of products.

In some batch operations, a second staging area is placed between the powder spray booth and the curing oven. In most batch operations, the powdered parts go directly into the curing oven. But, if your coating throughput is very high or you’re curing something that requires a long dwell-time, you may need this second area to store your previously coated parts away from shop traffic before they are placed in the curing oven.

IMPORTANT: Don’t let your powder coated parts wait too long before curing. Powder does not immediately fall off once a part has been coated. Good adhesion isn’t hard to achieve as long as you have a proper ground during application. Typically, uncured powder coating will adhere to the part for several hours with no ill effects. However, the longer you leave the powder uncured, the more exposure it has to moisture, handling damage, dust and airborne contaminants that cause imperfections in the cured finish.

Once you remove the cured objects from the oven, the racks and parts must have a place to cool before being handled. This final staging area is where the parts can adequately cool before assembly or packing. It’s very important to stage cured parts away from pretreatment areas and powder spraying operations to prevent accidental contamination of the powder finish before it has cooled and fully hardened.

A Custom Solution For Your Exact Needs

Reliant Finishing Systems manufactures over 250 standard powder spray booths, as well as fully custom booths built to client specifications. Our booth configurations are also available with matching powder curing ovens, wash stations, dry-off ovens and blast rooms. Our modular, perfectly-matched appliances are easily configured for a fully integrated powder coating line. Regardless of your finishing equipment needs–from a small batch oven or booth to a complex automated powder coating line–the specialists at Reliant Finishing Systems can help you determine exactly what equipment you need to get the best results. Let us provide you with a list of some of our very happy customers. We’ve worked with hundreds of unique layouts and design requirements, and our technicians have installed countless coating systems across the U.S.A. and abroad. When you’re ready for a new booth, oven or complete powder coating system, give us a call!

Five Things You Should Never Do With Your Batch Powder Coating Oven

Whether yoBatch Powder Curing Oven Control Panelu’ve just started coating or have been operating a batch powder coating system for years, you know that the coating oven is an expensive appliance and a vital part of your coating operation. Keeping your batch oven in good working order is critical to long-term success. A well-maintained powder coating oven can last for over a decade, produce thousands of high-quality parts for your customers and be a considerable source of income for your business.

However, a batch oven that is operated incorrectly can be a serious safety hazard that’s unreliable and can cause you nothing but problems and headaches. To help you avoid making a costly – and potentially dangerous – mistake, here are five things you should NEVER do when operating a powder coating oven.

1) Don’t Run The Oven Above The Recommended Temperature

Most batch powder coating ovens are rated for sustained operation at temperatures of up to 450° F, while some more expensive models are rated up to 500° F or higher. If you own a conventional 450° batch oven, jumping up from 380° to 480° in an attempt to save a few minutes of cure time will harm the equipment, possibly trip the safety devices (leading to downtime) and potentially damage the finish on your parts. Every powder is rated for a specific temperature range. Going above this range will make the finish brittle and less durable, and can cause discoloration issues. This is especially true with glossy white finishes. Also, the few extra minutes you might save aren’t worth voiding your warranty or damaging costly components, especially on a critical piece of equipment like a batch curing oven.

2) Don’t Reduce The Exhaust Airflow In An Attempt To Save On Heating Costs

All professional-grade gas fueled ovens are built to exhaust a certain amount of air whenever the oven is in operation. The exhaust causes the air to move in a particular pattern within the oven cabin, keeping the cabin a stable temperature throughout. If you reduce or eliminate the exhaust airflow, you can create hot and cold spots that weren’t there before. These temperature changes will cause the powder to overbake or underbake, resulting in poor finishes and lots of reworks.

You’ll also have problems with safety devices. If you disable the safeties to keep them from tripping, you are violating important safety codes and you’ll void your warranty, no matter who built your oven. Another problem is that if there isn’t enough air being exhausted from the oven, you can have significant heat loss at the doors or oven panel seams. You may also have problems getting the doors to latch properly.

3) Don’t Overload The Oven Trying To Increase Throughput

If too many objects and racks are added to the oven, there’s a high probability you will accidentally block the oven exhaust or airflow ducts inside the cabin. If the exhaust is blocked, it adds stress to the exhaust fan and can shorten the service life of both the fan and the drive motor. It can also promote hot spots inside the oven that can damage parts, rolling racks or the oven cabin itself. If the supply ducts from the heater are obstructed, the powder can get blown off the parts. A bigger problem arises if the airflow through the heat unit gets reduced. This not only kills fuel efficiency but it also causes the temperature inside the heat unit to skyrocket. This can result in the heat unit’s fan failing, reduced service life from the motor, erratic operation due to safety circuits being tripped and even structural damage to the heat unit.

4) Don’t Skip Maintenance

Remove-BoltNo matter how busy the coating line is, skipping scheduled maintenance will shorten the service life of important oven components and can lead to critical failures. The majority of service calls we receive regarding older ovens are linked to poor maintenance practices. Most of these calls come from successful powder coating shops that use their equipment daily and stay busy–but they learn the hard way that “we’ve been busy” is no excuse for avoiding routine maintenance procedures. Keep your oven clean. Service the burner regularly. Lubricate bearings as directed. Check ductwork for obstructions. Don’t let a nuisance issue, like a noisy exhaust fan or a worn-out door latch, result in costly downtime because you were too busy to deal with it when you first noticed it.

5) Don’t Install The Oven Too Close To Other Equipment Just To Save Shop Space

Batch Powder Coating Oven Maintenance Walkway

Make sure to allow for enough space around your coating oven to meet safety codes and allow for easy maintenance access.

From time to time we encounter a situation where a customer has installed his oven too close to his powder booth, his welding operation, a clean-up station, his blasting operation or some type of chemical pretreatment wash station. Not only does this violate safety codes, but debris, fumes or even powder from other appliances can cause problems with your oven or your finishes.

We were recently asked to troubleshoot problems with a high-end oven from another manufacturer. We discovered that the oven worked fine, but the parts were being exposed to WD-40 fumes during both the coating and cool-down stages—resulting in unacceptable finishes. Although this wasn’t damaging to the oven, similar exposure to airborne grit from blasting or pretreatment chemistry from a washer could have been.

Another common problem is when the “guts” of a powder coating oven get coated with a layer of powder over and over again during operation because of powder overspray from a nearby booth (usually one that needs a filter service). The burner safeties can cause the oven to shut down, the fan can come out of balance due to an uneven layer of melted powder and ductwork can become restricted. All of this can be prevented with proper planning and equipment placement.

Routine Maintenance and Scheduled Service Can Keep You In Operation For Years To Come

At Reliant Finishing Systems, we pride ourselves on providing some of the best and most efficient batch coating equipment on the market. By following these tips, making sure you’re following a set maintenance schedule and contacting us for service visits when you have problems, you can help increase the lifespan of your equipment and maximize your ROI.

Have any questions about powder coating equipment or need to schedule a service visit? Give us a call today.

Improving The Performance Of Your Batch Powder Curing Oven

Batch Powder Curing Oven From Reliant Finishing Systems If you use a walk-in sized batch powder curing oven for your powder coating operation, you may have questions about how to consistently get the best results from your equipment. The oven’s performance–particularly the air temperature and airflow inside the oven–can make or break the quality of your finished products.

These important tips can help you get the best finish possible from your curing oven:

Make Sure The Oven Is Sized Correctly For The Project

Powder coating ovens can be built to nearly any height, width or depth. The ideal size for your project is dependent upon what you are going to be coating. No matter what you want to coat, the entire object needs to fit inside the oven with room to spare. For more information on oven sizing guidelines, click here.

Keep Parts Away From Walls, Doors, Ductwork And Ceiling

Powder Coating Oven VentsDepending on which brand of oven you have, heated air is usually blown into the oven via ducts in the ceiling or wall, or sometimes both. When curing, make sure you have enough space between the ductwork and the parts. If the parts get too close to the ducts, the powder can get blown off and you will have to rework the part.

Likewise, if a part touches the oven’s interior, the powder is likely to either rub off completely or flake away during curing. In order to get a proper finish, the parts can’t touch the ceiling, ductwork or walls, and they can’t impede the operation of the doors or rub against them.

Also consider how the parts will be carried in and out of the batch powder curing oven. Most parts are hung on rolling racks (also called parts carts), so there has to be enough room for the rack to fit into the oven once the parts have been hung. If your rack bumps into the walls of the oven, the powder you applied can get knocked off.

Keep Parts Off The Ground

Just like you will need to allow for room near the walls, ceiling, doors and ductwork, you also need to avoid hanging parts so that they nearly drag the ground. If possible, the lowest part of the biggest parts should be 10” or more off the floor. This makes the temperature of the parts more uniform and allows the powder to cure more evenly. It also helps prevent dust contamination if the oven’s heat system blows dust and dirt from the floor onto the parts.

Routinely Check Your Batch Powder Curing Oven’s Temperature

Some ovens have better temperature uniformity than others, but none are perfectly uniform. Ovens with ceiling ducts are usually cooler at the floor than elsewhere. Ovens with wall ducts may be cooler in the corners, and possibly near the floor. It is recommended that you routinely check your oven’s temperature with an oven data recorder (a Datapaq or similar) and keep a log of the results. Get professional help fine tuning your oven and adjust your curing practices as needed.

Check Your Shop For Airflow Issues

Batch Powder Curing Oven - Doors OpenAlthough it might not be obvious, drafts and air currents in the shop influence the way an oven operates. Some days there may be giant wall-mounted vent fans in operation to help keep the shop cool or get rid of welding fumes. Other days there may be one or more heaters in operation to keep office or shop space warm. Many shops have roll-up doors that are constantly being opened and closed. Wind can blow into the building or move across openings and create an imperceptible vacuum or pressurize a shop in ways that can easily overcome a powerful fan system. All of these things can impact your oven’s performance.

If you notice a change in your oven’s performance, check for changes in the way air moves through your building. Is air blowing in from outside that wasn’t a few days ago? Were the building exhaust fans turned off but the vents left open? Have you started using an AC system or have you cranked up heaters that weren’t in use until recently? Does the oven only have problems when a roll-up door is opened or closed? Examining the airflow within the shop can often help you pinpoint oven operation issues.

Check Your Fuel Source When Local Usage Changes

Another factor that can make a huge difference in the way an oven runs is fuel supply. Whether your oven is burning LP or natural gas, changes in the fuel supply can cause problems that are almost impossible to trace. These issues can be due to weather changes, new construction near your shop, changes within your building, or changes to your style of use.

If an oven is calibrated during the summer, the gas supply may decrease during the winter because of increased demand. This may be due to your neighbors (especially if located near a hospital, apartments or a large office complex) or may be because you’re using more fuel to run heaters or gas-fueled appliances within your own building that are tied in to the same line feeding your batch powder curing oven.

A similar problem can occur if new apartments or other types of high-demand buildings are constructed near your building. Once occupied, they may cause changes to the fuel supply coming into your building. Along the same lines, if you add shop heaters, steam units, or additional ovens, it may reduce the amount of available LP or natural gas fuel.

Remember, gas pressure and gas volume are not the same thing. It is possible to have a situation where the pressure gauge shows plenty of pressure when the oven is at idle or turned off, but then have performance issues once the oven goes to high fire. This usually happens when the supply line or regulator is too small. The oven can also have problems if the supply has enough volume, but the pressure is too high (dangerous and can cause the safeties to trip) or too low (can cause the oven to fail to ignite or to take too long to get to curing temperature). For best results, the oven needs an adequate volume of gas delivered at just the right pressure.

Always Follow Safety Procedures

IMPORTANT: If your shop’s work schedule becomes busier or you change operators, it is possible to have oven issues crop up because of the way the oven is being used. One common problem is caused by operators opening the oven doors for loading/unloading while the oven is running. This is unsafe and can lead to property damage, serious injury or death. It also causes the heat system to burn a large amount of fuel as it tries to maintain curing temperature while heat is rapidly escaping from the oven through the open doors. Not only does this waste fuel, it can reduce the service life of expensive oven components because of the burner’s extremely high output. When you’re ready to open the oven doors, shut down the burner but leave the fans running. Turning off the fans while the oven is at curing temperature can cause them to warp or can cause related parts to fail prematurely.

Follow Factory Maintenance Recommendations And Usage Guidelines

Batch Powder Curing Oven Control PanelEvery powder coating oven manufacturer provides a maintenance schedule which outlines the safest and most effective ways to operate their equipment. These factory-recommended “best practices” describe the style of use that is safest, most efficient in terms of manpower, least expensive in terms of fuel use, least likely to result in down-time due to equipment repair, and most likely to prevent unusable powder coated parts that are rejected due to poor finish quality.

There’s a reason why successful shops that are noted for premium quality work or incredibly high throughput keep their equipment in top shape and operate it properly. Having a set schedule for cleaning, maintenance and lubrication of your batch powder curing oven and related equipment will help you get consistent, high-quality finishes. Similarly, only running the oven within recommended temperature ranges is not only more fuel-efficient, it is safer for your operators and less likely to damage parts. Oven providers typically offer strict guidelines designed to assure that you get the best results from your equipment and the highest level of efficiency. Following those guidelines will help save you from expensive equipment repairs and costly parts reworks due to bad finishes.

Need An Equipment Check-up?

Reliant Finishing Systems batch powder curing ovens are always set up by our factory-authorized technicians to provide performance that is well balanced. We want our ovens to reach operating temperature quickly, while burning as little fuel as possible, and we are committed to helping shop owners keep our equipment in the best operating condition possible.

If you have any service or maintenance issues, please give us a call today. Scheduling a visit from one of our factory-authorized technicians can help solve curing issues, improve your efficiency and increase the lifespan of your equipment. Available services include troubleshooting, Datapaq recording and line audits, preventative maintenance, and both routine and emergency repairs. Call today for more information or to schedule an appointment.