Reliant Finishing Systems Applications Specialist Bruce Chirrey has been in the industrial finishing industry for 25 years. He has held positions such as Field Technical Service, Applications Lab Manager, and Technical Sales Representative. For the past 15 years he has been instrumental in the implementation of several finishing lines, both liquid and powder, for such industrial clients as Kubota, John Deere, Masonite, Kelley Manufacturing, Albany Marine Base, and many others.
Industrial curing ovens provide heated curing for everything from foam dashboard components to composite aviation parts to assemblies held together with adhesives. These ovens can be used for finishing processes like flashing off painted surfaces, drying parts that have been washed or chemically pretreated, and curing parts that have been painted or powder coated. They are also used for heat treating metals and conditioning parts or raw materials.
There are two popular types of industrial curing ovens: continuous process ovens, sometimes called constant process ovens, and batch ovens. Continuous process ovens use a powered transport method, like an overhead conveyor, to move parts through the oven at a predetermined rate. Batch ovens are typically loaded with “batches” of parts or materials using carts, skates, or manual conveyors. Continuous process ovens may use ware openings in the equipment that allow parts to constantly move in and out without significant heat loss. Batch ovens will typically have insulated doors that are opened and closed as parts are loaded in or removed.
Continuous curing ovens are well-suited for situations that require less material handling and have fewer changes between materials or part sizes. These ovens typically require only a single operator, unlike batch ovens that may need workers to open and close the oven doors, manually transport the items being cured, and make adjustments when the parts or materials change. Constant process curing ovens tend to be more economical in the long run when dealing with a large volume of similar parts or materials, even though batch ovens cost much less and are more versatile.
Batch ovens are usually significantly less expensive than continuous curing oven systems, in part because they can be smaller. If you have a 40-minute curing routine and you need a transport rate of 4 feet per minute to meet your throughput requirements, you’ll need an oven large enough to allow the parts to travel 160’ inside the oven. If the parts are done in batches, it may be possible to process the same number of parts or more in an oven that is only 25’ long. This is because the parts can be left in place for the duration of the curing process. Batch curing ovens also offer a better solution when space is at a premium because the parts being loaded into them don’t have to move the same way every time and can be left in a staging area or moved around objects that are in their way when it is time to load or unload them. Unlike continuous process ovens, batch ovens are often loaded with parts that are transported on wheeled carts instead of parts that are being moved along a specific path via a powered conveyor.
Batch curing ovens work well when the volume of work is limited, or the parts being cured are varied. If your parts vary significantly in size or density, or you work with a variety of materials, it is challenging to efficiently utilize a constant process curing oven because the heating environment, airflow pattern, dwell time, and curing parameters cannot be substantially changed. This challenge is easily solved by curing different types of parts or materials in separate batches. You can change the control parameters to adjust for the curing specifications of each batch based on the size, density, material, and other traits of the particular load you are processing.
To get the best results, you need an accurate assessment of your exact curing needs. When determining the ideal curing solution for your application, you’ll need to know the details of the thermal processing routine you want to implement and how to integrate it into your workflow plans. You’ll also need to decide how much shop space you can use and what your budget will be for the curing equipment.
Reliant focuses on equipment solutions that are the best fit for your specific budget, workspace, and curing requirements. Our specialists will send you a free survey that asks about your throughput goals, the size of your parts, and the materials you’ll be working with, as well as your shop space, workflow, and budget. Once we get the information we need, our team will review the material and develop the most effective solutions for you. After we explain the solutions in detail, we will discuss acquisition timelines and installation requirements with you. Our goal is to assure that the solution you choose will smoothly and effectively integrate the curing process into your specific production environment.
The key to getting a good powder coated or painted finish is preparing the surface of the parts you are coating. If the part is not thoroughly cleaned and ready to accept powder or paint, the finished product may be compromised. There is nothing more frustrating than applying a top-notch coating only to get an unacceptable finish because the surface of the part wasn’t adequately cleaned. Depending on the nature of the material you are working with, chemical pretreatment and blasting with abrasive media are two popular choices for prepping parts.
Blasting does a great job of eliminating surface defects and trash like rust, mill scale, laser scale, welding splatter, and other surface contaminants. It also provides a textured surface for the powder or paint to grab on to while it starts to cure. If you are worried about powder coating adhesion, blasting is one of the best ways to prepare the metal.
Where to start?
Well, setting up a blasting process requires the purchase of a handful of key components. Let’s review what you’ll need and consider the critical information about each piece of equipment:
Air Compressor, Filtration, and Air Lines
This is probably the most important set of components to research thoroughly. Without the correct air volume and pressure, your blast pot will not function correctly. It’s also important that the compressed air delivered to your blasting equipment is dry, cool, and free of oil and contaminants. Moist blasting media will not blast correctly, and if the media is wet enough, it may not feed at all. If you live in an area with a hot, humid climate, a refrigerated air dryer after the compressor may be needed. In any case, you need to make sure that you have a good in-line filter system that will trap airborne contaminants in your air supply, as well as a desiccant type dryer with a drain if you don’t add a more expensive refrigerated dryer instead.
The compressed air lines you run are also critical. We’ve frequently seen coaters that have large compressors get sub-standard results from their blasting equipment. It’s almost always because they’ve choked down the air supply from their compressors by running small 1/4” to 1/2” air lines over long distances to save money on piping costs. Connect the blasting pot to your compressed air supply with piping that is at least as big as the fitting that is used by the blasting pot manufacturer at the point where the pot connects to your air lines. DO NOT run small piping and then adapt it up at the connection point of the pot. Smaller pots usually require 1” pipe while larger pots can need up to 2”. Don’t skimp on your air lines.
The distance from the compressor to your blasting equipment also matters. Even with smaller pots, once the compressor is more than about 200’ away, it may be necessary to upsize the piping to 1 ½” or 2” in order to get proper volume and pressure at the blast pot.
IMPORTANT: Read the set-up guide for your blasting equipment very carefully to avoid making costly modifications to your air piping after you’ve installed your equipment.
Another issue can occur when you run multiple machines off the same compressor. You can have trouble blasting because the airflow requirements of the blasting pot aren’t being met when the other equipment is in operation. Having a dedicated compressor just for your blasting operation is a good idea, especially if you are blasting on a daily basis.
Typically, most blasting pots require 80 PSI or more to function correctly. If you are using smaller media with a 3/16” nozzle orifice, then you’ll need a compressor that can consistently generate about 40 CFM. If you run a larger nozzle orifice, you will need a larger compressor. A 1/4” orifice needs about 70 CFM and a 5/16” orifice requires about 115 CFM.
When possible, we suggest using a rotary screw type compressor to power your blasting operation. Although more expensive than piston type compressors, they are better suited to an environment where they will see extended use at high CFM flow rates. Try to use a slightly larger compressor than what is detailed in the instructions for your equipment. We recommend that the compressor you use is sized so it can operate at 70-80% of its rated maximum output. This will extend its service life and assure that you aren’t at risk of “running the system dry” on days where you are blasting for long periods.
A blasting booth, also known as a blast booth or blast room, contains the dust and surface contamination removed by the blasting process and its overhead lights and dust collection system help the operator see his work. If you’ve ever watched someone try to blast without a booth, you know it’s a messy process and the equipment operator often seems to be struggling to see what he is doing.
Just like it’s important to have a booth to enclose the process and keep from contaminating the shop environment, it’s critical to have a dust collection system so the operator isn’t surrounded by a cloud of airborne dust while he works. Good visibility is critical for good results. Most blast rooms feature an exhaust with either cyclonic dust removal or an array of cartridge type filters that remove airborne dust particles. It’s important to understand that these filtration systems do not remove spent media or large pieces of debris from the booth. We’ll discuss reclamation systems that remove media and debris later in this article.
Most blast booths have plastic or rubberized shields to protect the walls from the constant abrasion of the blasting. Without these shields, blasting can eat away at the walls of booth in a matter of time. The rubberized shields also help keep the spent media from bouncing back onto the operator. This is especially valuable when using steel shot.
Blasting pots, also known as blasting pressure vessels, are usually measured in terms of how many cubic feet or pounds of blasting media they can hold. Common blast pot sizes range from 50-pound to 650-pound capacity. If you have a small shop that only does a couple small parts or a set of wheels per day, then the 50-pound pot might be fine. However, if you don’t want to be constantly refilling the pot, a 250-pound pot is usually the minimum for a full-service powder coating shop and a 450-pound or larger pot is common at larger job shops or in a production environment.
Using the smallest common nozzle orifice (3/16”), a pot can typically spray about 215-220 pounds of media in an hour if the operator is blasting non-stop for the entire hour without releasing the controls. The amount of media being used goes way up with a larger nozzle orifice. The difference in cost between a small pot and a large pot is minimal in comparison with the amount of time you burn up during the workday reloading a blast pot.
Blast Media Reclamation
Although not exactly a “best practices” approach, some smaller shops sweep up the spent media and put it through one or more screens to remove large particles. The material that falls through the screen is then reloaded by hand into the blast pot. This only works with media that can be reused.
If your shop does a good bit of blasting on a daily basis, you may want to consider a reclaim unit that will help you quickly reuse spent blast media. The most basic of these include a pick-up bin that is about the size of a mailbox. Spent media is swept into the bin and a powerful vacuum draws it into the reclaim unit where it is spun until debris and broken-down grit is separated into a trash barrel and the material that can be reused is then manually or automatically loaded into the blast pot. Larger, more sophisticated systems may include a grated floor or troughs in the floor that either rely on a vacuum system or a powered auger and bucket elevator to return spent media to the blast pot.
Blast Nozzle Selection
As stated before, the smallest blast nozzle orifice is usually 3/16”. We recommend trying to set up your blast process to use the smallest, least aggressive media possible. This will leave a smaller blast profile that has to be covered and “evened out” by powder or paint. Your blast media data sheet will indicate a mil profile that is left after blasting. The larger the mil profile, the more powder or paint it will take to achieve a smooth surface.
However, if you have a lot of deep rust or mill scale, you should try larger nozzles and suitable media to save time when blasting. Just remember to check the mil profile rating on the media and that will tell you the basic powder mil amount needed to cover the profile. For example, if you have a 1.5 mil profile, you will need at least 3.5 mils of cured powder to adequately cover the steel and fill in all the recesses caused by the blasting.
Remember, if you use larger nozzles, your air consumption will go up—way up. Make sure you have enough compressor capacity to accommodate the larger nozzles, or you’ll be frustrated by the results.
Blast Media Selection
Most people think of blasting as sand blasting. Sand is not recommended anymore due to the health hazards of silicosis. Sand breaks down and forms dust clouds that remain suspended in the air. Even in the most controlled environment there is a chance that these extremely fine particles can be inhaled and cause problems. Therefore, these other medias are now commonly recommended and are silicone free.
Aluminum Oxide – This popular abrasive has been in use for decades. Countless grit sizes available. Reusable and has a great shelf life. Aggressive cutting and hard enough to texture stainless and titanium. Requires care when working with softer metals.
Coal Slag – Many different sizes of media are available. Good cutting power for rust or old paint. Relatively inexpensive but not reusable.
Eco-Friendly/Organic – Walnut shells and corn cob fragments are among these types of media. Bio-degradable and similar to glass in maintaining metal details on softer metals.
Garnet – Different grits available. Cleaner and can be more affordable than coal slag. Very consistent mil profile. Reusable and gives predictable results.
Glass or Glass Beads – Mostly for fine blasting where metal details need to be maintained. Also good for softer metals. Beads are reusable and crushed glass is disposable.
Steel Shot – Probably the world’s most popular reusable blasting media. Does not degrade with multiple uses like other media (most reusable media types can’t be used more than 3-6 times). Can be contaminated by oils, so not the best choice for oily parts. A little too harsh for fine finishes and soft metals. Requires robust reclamation equipment to effectively reuse.
These are the main types of blasting media we see in use by small powder shops and big manufacturers alike. There are others, like grit made from recycled plastic for applications where little surface texturing is desired, or silicon carbide for when a heavily etched surface is desired. If possible, start a relationship with a local blast media supplier who can help you find the right media for your blasting operation.
Personal Protective Equipment (PPE)
If your shops blast 6-8 hours a day, OSHA says you should supply your operator with a full suit and gloves, along with an enclosed helmet that supplies air for him to breath. The air supply needs to have a carbon dioxide monitor and an inline cooling unit. The helmet/respirator needs to be supplied with Grade “D” compressed air. Each operator needs their own suit and helmet. Make sure if you use the air from the same compressor as the blasting pot, that the plumbing does not rob air from the operator or the pot. Get some extra face shields, fittings, gloves, and a spare cooling unit to avoid downtime during breakdowns.
What Can You Blast?
Blasting pots and blast media are most commonly used for preparing regular mild carbon steel. If you are blasting aluminum, lower pressures (40-60 PSI) and smaller, less aggressive media are recommended so you do not damage the surface of the parts. Large, aggressive types of grit can tear into the metal and cause finishing inconsistencies like dull spots, rough textures, and irregular gassing out of the metal. Steel shot is also not a great choice for aluminum or stainless steel since the shot can leave behind carbon steel residue that may interfere with the properties of those parts.
Setting up the Blast Pot
Fill the pot with blast media but do not exceed the bottom of the sealing plunger.
Adjusting the blast pot is usually a two-person operation. One operator will handle the nozzle while the other slowly increases the media feed at the bottom of the pot while the nozzle is triggered. You want to barely be able to see the media coming out of the nozzle. Too much media will clog the hose, slow down the media velocity, waste the media, and yield unacceptable results.
Watch your air pressure when triggering the nozzle. If your air pressure drops below about 20 PSI while the nozzle is triggered, then you have an air volume problem. Look for airline chokepoints and/or stop using other machinery that requires air if they are connected to the compressor you use for blasting.
Need Help? We’re Here for You.
Hopefully, this guide will help you plan the set-up of your blasting operation. As mentioned before, carefully review the literature for the specific blasting pot and nozzle orifice you purchase and be sure to get a big enough compressor to operate your system properly.
In addition to manufacturing professional powder coating equipment, Reliant also provides a wide range of services to help your existing finishing operation run smoothly–from on-site troubleshooting to training, equipment refurbishment, and more. Call us today at (877) 418-5550.
Stripping the finish off coated parts can be a real headache for most powder coaters. There are many ways to remove coating from a part prior to re-coating with powder, but we will focus on two of the most popular stripping methods: mechanical stripping using abrasive blasting and chemical stripping using dip tanks.
Mechanical stripping typically involves sanding, buffing, or blasting the old coating off.
Sanding or buffing is pretty straightforward, but it is usually the most labor-intensive way to remove a previously applied finish. For re-coating parts that have a powder coated finish, it can be a valuable technique. Unfortunately, taking the part down to bare metal requires a lot of care, effort, and time.
Blasting is a better option to strip parts when other methods are not available or allowed. Choosing the correct abrasive media is key. Most blasting operations are set up to clean and prepare raw metal for coating. It isn’t uncommon to see a blasting system used to remove scale and rust, as well as provide a bit of texture to the surface of the parts that need to be coated.
Stripping paint or powder coating from a part is a similar but slightly different process. When cleaning raw metal parts, less abrasive media like sand or glass may be used to help maintain the surface details of the parts and prevent accidental damage. Stripping parts usually calls for more aggressive media like steel shot, garnet, or aluminum oxide.
All these abrasive medias have different grits, which leave different mil profiles. Remember, if you leave a deep mil profile, it will require more powder to cover up the rough texture left by the aggressive blasting. If you choose the finer grits, you will spend more time blasting the part, but you can preserve fine surface details such as decorative scrolling. It really is a balancing act to figure out how much labor you want to invest versus how smooth you need the final appearance of the coated part to be. On one hand, more blasting time obviously means your costs will go up. On the other hand, using larger grits will require you to apply more powder to cover the part and you may have to address a more pronounced “orange peel” look on the surface of the finished part.
Chemical stripping can be a viable option for those coaters who re-finish a high number of parts on a daily or weekly basis, especially if they aren’t particularly large. If your customers bring in a lot of stripping work, dedicated strip tanks can remove previously applied coatings without damaging the profiles of the parts being refinished.
Warning! This solvent is very aggressive and all proper personal protection equipment should be used when dealing with it and similar stripping agents. Face shields and goggles, long chemical-resistant rubber gloves, a respirator appropriate for solvent fumes, and Tyvek suits are recommended when handling parts during stripping, as is thoroughly rinsing parts or areas of incidental contact with water to reduce the concentration of these chemicals and halt their effect.
If stripping parts is a regular occurrence, strip tanks like the ones offered by Greensolv (https://www.greensolv.com/rims-stripping) provide an easily repeatable process for removing old coatings and cleaning parts like wheels prior to refinishing. They usually recondition the stripping solvent and have a way to filter trash and old coating material out of the tank using a circulation system with filtration.
Whether stripping using mechanical or chemical methods, once the parts are taken down to bare metal, they no longer have any rust protection and can flash rust unless immediately sealed/treated and then coated.
Need Help? We’re Here for You!
In addition to manufacturing, installing, and supporting our own powder coating equipment, Reliant also provides a wide range of services to help your existing finishing operation run smoothly–from on-site troubleshooting to training & consulting, equipment refurbishment, and more. Call us today at (877) 418-5550.
For this month’s Customer Spotlight, we spoke with Charles Boyce, President and CEO of Boyce Technologies of Long Island City, New York. Boyce produces easy-to-use and reliable safety and communications equipment for the New York subway system and other clients. After seeing the impact of the current health crisis, Boyce found a way to step up and make a difference.
Q: Charles, we’ve heard that your company is part of the effort to mass produce ventilators in response to the COVID-19 situation. Can you tell us a bit more about your decision to focus your manufacturing on this effort?
A: A few weeks ago, I was driving to work thinking about how the pandemic was unfolding. Being an essential business, it was very emotional bringing people into the factory to work. I was really wondering what type of disaster was about to befall my city, New York.
The difficulty of finding PPE was already an issue and we were producing tens of thousands of face shields a week. I felt like I wasn’t doing enough, and I always brag about being able to do anything. So, I went into work, met with the engineers, and said we were going to make ventilators.
Coincidentally, a friend from New Lab called that same morning to ask if I was interested in producing a ventilator that they were designing. I told him I had already started. We created a team of companies from Boyce Technologies, New Lab, and 10X Beta, and began working with the MIT designs. Open source was not an option due to the fact that ventilators can hurt you as quickly as help you, so we focused on making this a commercially viable product. Our adaptive engineered manufacturing process allowed us to invent and produce at the same time. About 25 versions of the ventilator went into the trash. If we waited to do everything consecutively, that would have meant 6 months to a year for the design process. We did it in a month.
Q: Prior to your efforts with ventilators, what was Boyce Technologies manufacturing?
A: Boyce Technologies manufactures life safety and security equipment for mass transit.
Q: How did you get your start? Can you share a little company history?
A: About 30 years ago, right out of college, I was called by a friend to see if I could solve a problem in electronics security for the New York city transit system. I designed the emergency booth communication system. After that successful project, I continued to design systems for the transit system for over 25 years. About seven years ago, I changed careers from just designing and project managing to the creation of a new company that still did the design, but also included the fabrication of these systems. This new company has large scale and vertical manufacturing capabilities all under one roof. This flexibility has allowed us to change iterations to something like the new ventilator project extremely quickly.
Q: What obstacles did you face along the way?
A: Mostly they were supply chain-oriented, which is why I decided to bring as much as possible under one roof. The main challenge I have right now is designing a product that is immediately scalable.
Q: Did your business model allow for your flexibility in changing product lines into a ventilator production facility?
A: A few weeks ago, I didn’t know what a ventilator was. All electronic products have a micro-controller, a circuit board, a chassis, etc. It can be a toaster, refrigerator, or a ventilator. It’s like eating a meal at night, you only have a few choices like beef, chicken, lamb, or fish. Your choices are limited. Being a truly vertically integrated manufacturing facility made this a very easy adaptation. It took about three days and it will take about three days to go back to what we were producing before.
Q: How has Reliant Finishing Equipment helped in your process?
A: We have a very large powder coating line in a compact space. We run it 24/7. The ability to have in-house finishing is an important part of our process. If parts don’t look good, they aren’t good. They need to be durable and clean, especially for medical equipment. Having a fast finishing system enables us to quickly produce and ship 300+ ventilators per day.
Q: Why did you decide to purchase Reliant equipment?
A: A word of mouth recommendation from a powder coater we used to use, directed us to contact Reliant. Reliant was very responsive and flexible in working with the space that we had within the delivery times that we needed. Agility, offering a turn-key system, and being a U.S. manufacturer has made it a pleasure working with Reliant. I wouldn’t go anywhere else.
Q: Can you give us your thoughts on the future of American manufacturing?
A: Overseas dependency has hurt the U.S. Delivery times, loss of control, and design laziness have been revealed as problematic. It’s been time for manufacturing to return to the U.S. We didn’t predict a global event such as this, but we did not want to be controlled by sub-contractors of any sort.
At Boyce, we’re expanding and will be quadrupled in size in a couple of years. I think this pandemic has proven that we need to be more self-sufficient–and that’s an understatement. Boyce Technologies is well-positioned to be a model of adaptive engineered manufacturing. We are very proud to be located in New York City, the most amazing and powerful city in the world!
Charles, thank you so much for your time and your company’s awesome support of our country’s medical system during this crisis.
With the current Covid-19 pandemic occurring, weaknesses in the nation’s supply of medical equipment have been revealed. News outlets have reported on breakdowns with overseas shipments of vital medical equipment due to shelter-in-place policies, as well as geo-political delays that seem unlikely to resolve quickly. Quality also seems to be an issue, since China has implemented more export inspections:
All these factors will motivate the U.S. medical equipment industry to relocate some of its manufacturing back to the United States. This will lead to opportunities fabricating and coating the parts needed to make respirators/ventilators, N95 masks, other PPE supplies, hospital beds, etc. An uptick in this part of the manufacturing and finishing market is already underway.
One of the preferred coatings for steel or aluminum medical equipment is powder coating. This is due to its superior hardness/durability and chemical resistance. The chemical resistance of polyester powder makes it one of the most easily sanitized painted surfaces. Polyester powder coating is resistant to all the CDC-recommended sanitization chemicals, such as distilled water, bleach, hydrogen peroxide, ammonia, alcohol, phenolics, steam, and UV light, per the BIMFA clean guide:
Some hospitals and laboratories are specifying anti-microbial coatings. These coatings contain a small amount of silver that is safe for human contact but inhibits the growth of microbes. This requires a specialty powder that is applied just like any other polyester powder. It also has been used for children’s playground equipment and food processing equipment. Powder manufacturers such as PPG have product lines for these applications:
There are immediate and future opportunities for fabricators and coating shops. Large medical equipment manufacturers will be setting up new operations in the U.S. They are going to need fabricated carts, frames, furniture, electronics housings, and durable parts that meet the needs of healthcare facilities in the United States. Other industries might migrate to more durable finishes as well, due to the sanitization-friendly nature of powder coatings.
If you have any questions about how to set-up a powder finishing operation or convert to anti-microbial powders, please contact our technical sales professionals here or check out our resources page for valuable information.
In the first installment of Cleaning and Pretreatment, we covered the basics of metal preparation. We discussed the techniques that you’ll use for about 75% of the finishing industry’s standards. For most job shops and small manufacturers, these metal preparation techniques are all you will need.
But what if you’re approached by a customer with a specific powder coating requirement that is quite demanding? Is your basic pretreatment process going to be enough? Probably not.
If high-performance and long-lasting powder coating results are important to you and your clients, the only way to deliver those results is by upgrading your pretreatment process.
Powder Coating Standards & Testing
When talking about standards, your customers will have one main question when it comes to the coatings you apply:
How long and how well does the coating protect the metal?
To find the answer, you have to test.
The primary industry test that measures how your coating (and, indirectly, your pretreatment process) performs is called a salt spray chamber test. During this test, coated samples are placed in a salt spray chamber where the samples are periodically sprayed with warm saltwater. These tests can last up to thousands of hours.
Typically, these painted samples have an “X” scribed or cut into the middle of the panel, so that bare metal is exposed directly to the salt spray. The objective of the test is to see how much rust or paint blistering occurs at the scribed X. The test item fails when rust or blistering creeps beyond a set distance from the X-shaped penetration through the coating. This failure measurement is usually ¼ inch, but in extreme cases where coating performance must be carefully monitored, the failure measurement can be small as 1/8″ (examples include some high-performance or military grade coatings).
All salt spray chamber tests will include a stated hour requirement and a failure definition. As an example, it might be that the X-scribed sample must withstand 500 hours of salt spray with no more than ¼ inch of creep. The test will then be run until the sample successfully reaches 500 hours or until the rust or blistering creeps more than ¼ inch from the X. If the sample fails before 500 hours, the lab will let you know how long the sample was tested before the failure point was reached. Typically, these results are provided in 25-hour increments. So, a failed sample might be rated at 425 or 450 hours. This is a standardized way of rating performance because most labs check samples only once daily.
Before performing a salt spray chamber test, check your customers’ specifications for the measurement and the standard. There are different standards used by the American Society for Testing and Materials (ASTM) that refer to salt spray hours, so make sure you get the correct documentation from your customer if you must pass a specific test.
Where Can You Get A Salt Spray Test?
Most manufacturers and job shops have their powder vendors perform salt spray tests. This is typically done free of charge for established customers. Of course, larger powder customers get preferential treatment when booking tests, so if you’re in a crunch, you can contact an independent lab that will test your samples for a fee. It isn’t uncommon when bidding on a large contract to use an independent testing lab to quickly demonstrate to a potential customer that you can meet their finish requirements.
Remember, 500 hours is about 21 days, so passing that test will require the sample to be in the salt spray chamber for three full weeks. A 1000-hour test takes a month and a half.
Some larger consumers of powder coated components, like John Deere and the U.S. military, have their own labs with salt spray chambers that they use to certify qualified suppliers. Before submitting your samples to one of these organizations, make certain the samples are representative of your capabilities and have been prepared correctly.
Pretreatment Guidelines For Coaters
Below is a general pretreatment guideline. Use it to determine the number of salt spray hours your current process can achieve and what to consider when increasing your coatings performance. This is only a guideline and doesn’t replace a salt spray chamber test.
50 hours salt spray: as a reference, this can be achieved using clean metal (free of obvious rust, oil, grease, dirt, or other visible contaminants) with a single coat of a typical industrial enamel wet paint
250 hours salt spray: clean metal with a single coat of a typical polyester powder paint
500 hours salt spray: clean metal treated with a phosphate/non-phosphate chemistry, which is either dried in place or removed in one rinse step, followed by one coat of polyester powder paint
750 hours salt spray: clean metal that is washed, rinsed, then treated with a phosphate /non-phosphate dry-in-place chemistry/sealer, followed by one coat of polyester powder paint
Clean metal coated with one coat of zinc-rich powder primer and one coat of a polyester powder topcoat
1000 hours salt spray: clean metal that is washed, rinsed, treated with a phosphate/non-phosphate chemistry, rinsed again, sealed (or rinsed a third time, often using water that has been treated to remove minerals), followed by one coat of polyester powder paint
Clean metal coated with one coat of zinc-rich powder primer and one coat of a polyester powder topcoat
2000-3000 hours of salt spray: clean metal that is washed, rinsed, rinsed a second time, treated with a phosphate/non-phosphate chemistry, rinsed a third time, sealed, rinsed a fourth time using deionized/demineralized water, followed by one coat of zinc-rich powder primer and one coat of a urethane powder topcoat
The greater the performance requirements for the coating, the more steps you need to take. Also, once you get to a 750 hour or greater standard, you will almost certainly need an automated pretreatment system with a powered conveyor moving parts through it at a fixed rate. While you can achieve 750 hours with a manual wash, it will take multiple chemicals and a good system that can switch between them without contamination issues.
Many smaller shops use a zinc-rich epoxy powder primer under a polyester topcoat to get good salt spray results without an expensive multi-stage pretreatment system. The only downside to this approach is that you must powder coat your parts twice. Properly applied and cured epoxy primer on clean metal can improve salt spray test results by 500 to 750 hours.
Increasing your pretreatment capabilities is great for your coating performance, but it adds a new problem to your shop – waste disposal. One of the main concerns we hear from customers who want to pretreat to a higher standard is that they’re worried about getting in trouble for violating waste disposal regulations. We’re constantly asked, “how do I get rid of the pretreatment waste?” The answer is to ask your local authorities.
Pretreatment waste can be costly to manage and mishandling your waste can have very real consequences for the environment. Here’s a list that should help save you from incurring penalties from local, state, and federal environmental agencies. Following these guidelines also protects your local drinking water supply from being contaminated by heavy metals or other harmful waste. Always check with local authorities BEFORE developing a waste disposal plan.
Don’t dump the waste into a lake, pond, river, creek, or other water source!
Don’t dump the waste down a storm drain!
Don’t dump the waste into a ditch or onto the ground!
Don’t dump the waste into your septic tank!
Don’t flush the waste down the toilet!
Do check with your local city and/or county water authority. If you are on a sewer system, they should have guidelines on what can go into the sewer system. Ask for permission – not forgiveness – in this situation. You may have to get some waste samples tested at a lab for their approval.
Do check with your chemical supplier to get suggestions on the best way to dispose of the waste created.
Do contact a local industrial plumber. He may have some good suggestions from other companies he has worked with in the area.
Do contain the waste water in a basin or sealed concrete barrier. It may be possible for the water to evaporate and you can shovel the waste into a drum for disposal if you run a small operation.
Do check local waste disposal companies and ask what they require to pick up waste water in highly restricted areas.
As we’ve pointed out in this article, there are very real costs associated with producing powder coated finishes that offer the highest levels of performance. For some shops these costs will be prohibitive, but for many others they represent a reasonable price to pay for the opportunity to attract and retain lucrative accounts. Because not all shops are equipped to provide 1000-hour finishes, the amount of competition for those jobs is smaller, and the profits are typically larger.
Which Pretreatment Option is Best For Your Business?
Adding steps to your pretreatment process can greatly expand your clientele, as many larger construction and military projects require exact coating standards. Showing you can meet those standards allows you to bid for more work at a higher rate. On the other hand, especially for smaller shops, the extra time it takes – not only to produce the next part but to manage the waste – may impact the bottom line. If you are wondering whether a multi-stage pretreatment process is right for your business, check out our Resources page for more information or give us a call and consult with one of our systems specialists.
One of the biggest issues we see with existing powder coating systems is the lack of routine powder spray gun maintenance. When we ask about their maintenance routines, we find many operators and managers aren’t sure how to care for their powder guns and powder application systems. They also don’t have common replacement parts on hand and often don’t know where to identify them in their manuals.
If you’re one of those people, we can help!
Let’s start by covering some basic maintenance steps and then I’ll provide a list of replacement parts for three of the most common spray systems. To make things as easy as possible, at the end of the article I’ve also included the names and parts numbers for all the major powder gun manufacturers, so you can get the right part when you need it.
Powder Gun Maintenance: Grounding
OK, so grounding issues may or may not be related to gun maintenance, but they are a common cause of finishing system headaches. If you’re using a good quality powder and a large portion of your sprayed powder is falling to the floor or getting drawn into the exhaust filters without sticking to your parts, it may be due to poor grounding. A good ground is something you usually don’t have to worry about with a new system, but over time the system becomes less efficient without vigorous preventative maintenance.
Loss of ground can cause major problems with your finishing process, but, with a little bit of preventative care, you can avoid grounding issues and keep your transfer efficiency high. (For more information about grounding, click here.)
What causes grounding problems? They can be due to coated hooks, coated racks/hanging bars, poor grounding wire contact, gun issues, or operator error.
Coated Hooks: Hooks start losing their ground after about 4-6 uses. You should either clean them or replace them frequently enough that your parts maintain a good ground. Baked-on powder can be removed using heat, chemicals, or mechanical action like blasting or grinding. Your hooks need immediate attention if you are getting popping sounds and small electrostatic arcs from the hooks to the racks or hanging bars.
Coated Racks/Hanging Bars: Treat them the same as hooks. After 4-6 times through the coating process, you should grind, brush, or blast the excess powder off the rack or bar at the hook attachment areas or burn off the coating build up using a burn-off oven. Hanging bars can sometimes be cleaned using chemicals, but, because of their size, it is almost impossible to clean racks without burning off the overspray or removing it mechanically.
Check Your Grounding Wire: The grounding wires get close to the shop floor at the point where they attach to your grounding rod. It’s easy for them to get run over by racks and forklifts throughout the workday. Sometimes there is a break in the wire that is not easily visible through the sheathing. Use the back-up grounding wire provided with the spray gun system and compare results. If you are only using the grounding wire supplied with the system or you have attached a ground wire to equipment that is bolted to the floor, you can improve your ground immensely by using an 8’ grounding rod (preferably copper) and a relatively short run of grounding wire. Bury the rod right next to the booth. You can also get a much better ground using thicker wire and better clamps to attach to your racks or conveyor. Although there isn’t a “perfect” gauge size for powder system grounding wires, bigger is better–think jumper cables instead of speaker wire. The same goes for clamps–don’t cheap out.
Pro Tip: In some areas you can measurably improve your ground by routinely pouring water into the hole where the grounding rod was buried. Slowly pour water around the grounding rod until it begins to overflow from the top of the hole. This may take only a few ounces or could take over a gallon.
Check the Gun: If everything else checks out but there is still a lot of powder falling to the floor, getting sucked into the filters, or accumulating on the operator, make sure the tip of the powder gun (the one that has the electrode) has not been dropped or otherwise damaged. At normal settings, you should be getting some wrap coverage on the back of your parts and you should be able to feel the electrostatic field with the gun trigger pulled and your arm close to the tip of the gun. If you don’t feel your arm hairs raise when you squeeze the trigger, the probe or the main electronics could be damaged or not making contact somewhere.
Check Yourself: People can get so used to doing a task that they assume they’ve done it correctly without checking. Even the best operators can forget to clamp on the ground wire. If you suddenly see a decline in system performance, make sure the ground wire is attached and the gun settings weren’t changed by accident.
Powder Gun Maintenance: System Cleaning
Keeping your gun system clean should be part of your routine maintenance. A few different types of system cleaning/flushing should be done on a regular basis to keep your gun in good shape.
End of Day: If you’re NOT changing colors for the next shift, flushing the powder through the hose is a basic end-of-day cleaning routine. To do this, pull the pick-up tube out of the powder box or disconnect the hose from the hopper and pull the trigger until no powder is discharged. Remember, powder in the lines can lead to big start-up surges and possible impact fusion (slightly melted powder) sticking in the corners and hard to reach areas.
It’s also a good idea to wipe down or blow off the gun/unit every day, which will help keep powder from building up on the displays and possibly fouling the electronics. While cleaning up, check out wear items for possible replacement.
Color Change: Like above, flush the old powder and lightly clean all components. In addition, break down the gun and either shoot a foam earplug through the powder hose to scrape powder out of the line or change hoses. Investigate wear items for possible replacement (see below).
End of Week: Repeat your color change clean but take extra time looking at all the places where powder is building up. Use cotton swabs, like Q-Tips, and isopropyl alcohol to clean those hard to reach spots that are not blown out adequately by air. Check all wear items and replace if needed. Blow out the gun stand, especially in the vibratory box crevices. Sweep around gun area. Finally, wipe down both the display and the gun with isopropyl alcohol.
Wear Parts and Extra Hoses
Wear parts and hoses are the main extra items you need in order to keep your system running (barring an electrical component failure). Powder coating media is somewhat abrasive and there are a couple areas that take most of the punishment in manual systems.
Venturi Sleeve: The most common wear part is the venturi sleeve. This is the white plastic nozzle that the hose assembly hooks up to on the powder pump. Different manufacturers call it by different part names and numbers but I’ll refer to it as a venturi sleeve. The sleeve takes the powder and condenses it for travel up the hose to the gun. It accelerates the powder by condensing the volume of air, so the sleeve naturally gets hit with pressurized particles. The wear from the propelled powder hollows out the tube and sometimes cuts grooves into the sleeve. If it goes on for too long, the powder pump starts to become less efficient and the gun will surge.
Before that happens, you should check the sleeve every time you do a color change or end-of-week cleaning. This is a very inexpensive part, so it is worth having a couple around as replacements.
Powder Hose: The next replacement item you’ll want on-hand is an extra powder hose. Hoses can get run over, cut, pinched, and damaged by just about everything that takes place in a typical shop environment. I always recommend keeping at least one or two precut hoses available for quick replacement. Another use for extra hoses is quicker and more thorough color changes. If you only have three main colors, then there are advantages to having three hoses to insure less powder contamination and quicker color changes. If you clear coat, I highly recommend a hose dedicated solely to clear coat. Hoses also need a couple fittings which are wear items themselves. All manual guns have connections for the gun and the pump at opposite ends of the hose.
Powder Gun Tip: The last common replacement item I recommend always having on-hand is an extra gun tip. Tips take a lot of punishment from both the powder and the shop environment. With a lot of powder use, the tips can start to warp and cause application issues. Also, if the gun is dropped (and it will be), most likely it is going to land on the tip. Fortunately, the electrode is usually protected.
Where can you find replacement parts?
The “big three” professional-quality powder application gun manufacturers, Wagner, Gema, and Nordson, use different names and catalog numbers for the wear parts I’ve mentioned above. To help you find the part you need quickly, I’ve included the names, descriptions and part numbers you’ll need when ordering the parts for your particular powder gun system.
Manufacturer & Model
Wagner Sprint X
Annular Gap Collector Nozzle
Gema Optiflex 2
Nordson Encore XT
Manufacturer & Model
Wagner Sprint X
Powder Hose 11mm
Gema Optiflex 2
Hose, Antistatic, 10mm
Norson Encore XT
11mm Powder Hose
Hose Connectors to Gun
Manufacturer & Model
Wagner Sprint X
Hose Take Up, D10-12, Complete
Gema Optiflex 2
10mm Hose Connection
Norson Encore XT
Kit, Hose Adapter
Hose Connectors to Pump
Manufacturer & Model
Wagner Sprint X
Sealing Ring, Conductive
Gema Optiflex 2
Norson Encore XT
Manufacturer & Model
Wagner Sprint X
Fan Spray Nozzle, Complete
Gema Optiflex 2
Flat Jet Nozzle
Norson Encore XT
Nozzle, Flat Spray
These are the main items I would always keep at your facility to prevent a lengthy production stoppage due to a simple powder gun issue. If your budget allows, a secondary gun system is always good to have as a back-up. That way you always have at least one gun in operation if the other needs to be sent off for major repair.
For more information about the different powder gun systems, check out my comparison article here. If you’d like even more information about powder coating in general, along with equipment guides that explain what you’ll need to get professional quality powder coated finishes, check out our Resources page.
During my training sessions, I get a lot of questions about three-step specialty finishes. Let’s look at the three-step process, and I’ll provide practical information and tips that should be helpful for all coaters. Knowing how to do a three-step finish can improve the quality of your work – even if you never attempt this specific technique.
Although there are other high quality products on the market, I’m going to highlight two separate coatings systems that I have personally used: Tiger Drylac and Prismatic Powders.
Both coatings manufacturers require a clean part that is free from oils, waxes, surface rust, scale, and other contaminants or soils. Most custom powder coating shops satisfy this requirement by blasting the part with sand or some other type of blast media such as garnet or glass. Which process you use depends on how rough your metal is and how much detail you want the coating to highlight.
For example, if you have a steel wheel that has been in the back lot for a year, you are going to have to use an aggressive media to clean all the rust and debris. However, if you are using a laser etched aluminum wheel, you will want as fine a media as possible. For extreme detail, you may just want to use a chemical cleaner or acid-etch so all the surface detail will come through the finish. (For more information about what you need for blasting, click here.)
Chemical pretreatment is frequently used to prepare metal for coating and is sometimes just as necessary as blasting. Because the surface is so slick, aluminum parts and wheels can benefit from a cleaner/sealer that will promote adhesion of the coating. A cleaner/phosphate solution over steel can give additional protection if the coating is ever scratched or chipped in the field. (For more information about pretreatment, read our pretreatment primer.)
Pre-baking the part is usually the next step. This ensures all the water from pretreatment is removed, but drying the part isn’t the only reason pre-baking can help your finishes. If you are coating cast wheels and parts, the casting sometimes traps gasses in the metal. These gasses are only released when exposed to high heat – like the powder curing cycle. When trapped gasses come out during the cure, it creates bubbles and pinholes in the finish. (link to pinholes and outgassing article) By heating the parts prior to coating, the gasses can be released without damaging the finish.
Other metals such at hot-rolled steel, galvanized, or galvaneal can also have gas and oil trapped in them. Steam cleaning might work, but if you still notice oil and bubbles in your finish, start pre-baking your parts. This will help remove the hidden contaminants that can resurface as the part is being baked.
Tiger Drylac Candy System
The Tiger Drylac system recommends a three coat process. The chrome primer, the candy transparent coating, and then the clear topcoat.
Tiger Drylac provides three different primers that can be used, and each will give different end results depending on which color you choose. Of the three, the Kromezone primer seems to be the most reflective. Tiger recommends a full cure cycle on the primer of 10 minutes at 392° F metal temperature.
The next two steps are the tricky part! After the primer has been applied and cured, the candy color is applied at about 2 mils and cured for 5 minutes at 392° F metal temperature. This is not a full cure but rather a pre-gel cure. This helps intercoat adhesion between the candy layer and the final clear layer.
The final coat is the clearcoat and should be sprayed lightly over the candy coat. The cure time for the Tiger Drylac Clear Series 38/00001 is 15 minutes at 392° F metal/substrate temperature.
The last two steps usually require spraying onto a hot part, which can be challenging. Unless you are careful, spraying hot parts can lead to heavier coating thicknesses than you may want. Anytime the part is above 170° F, powder will melt as it starts to contact the metal or the coating that has already been applied to the metal. This can be a good thing, as it will help with deep corners and tough angles that are normally difficult to get powder to electrostatically stick to. However, it can also hurt you by building the final coat too quickly. During this stage remember that the powder output might have to be turned down or your movement may need to speed up as you go through the spray pattern in order to keep the dry mils around 2. You can always just let the part cool down to 150° F or less before spraying to avoid potential issues.
Prismatic Powder Illusion System
The Prismatic Powder system is like the Tiger Drylac system with a few exceptions:
The Super Chrome primer cure is higher.
A one-coat system is possible if the metal is shiny to begin with.
A clear topcoat is not required in some series (PPS series).
The Illusion system can be used with various gloss topcoats.
When using the Prismatic Powder, the first coat can be a very highly reflective coating they call Super Chrome. This product can be cured at 400° F but seems to work best at about 450° F metal temperature for 12 minutes. They also recommend when you apply the coating to set your kV control to 45. Higher voltage could cause the metallic content in the coating material to develop unusual patterns as it is applied.
The Illusion series from Prismatic Powder has an uncommon gel time which may take you some practice to master. The instructions state the gel time is 2 minutes after the powder flows to a gloss at 400° F. What that means is you set your oven to 400° F and keep an eye on the parts as they cure. As soon as the powder melts to a gloss, start a 2-minute timer. When the timer is done, pull the part out and let it cool to 150° F.
Watch your parts carefully during this process. The metal thickness of your parts affects when the powder starts to uniformly melt. If you cure the gloss too much, you risk de-lamination of the final clear coat. This is a perfect example of why you should always test on some scrap metal or broken parts to get your process debugged before trying it on production parts
After this Illusion Purple basecoat cooled down, I applied a clear. I used Casper Clear, a low-gloss clear topcoat. The application was about 2 mils at a 35 kV setting.
The reason for the lower setting is because the part is somewhat insulated by the previous two coats, so it’s better to treat it like a repaint. The reason you turn down your kV setting for repaints is so you don’t build up too much charge on the part, which can repel the powder in places.
After spraying a light coat I put this wheel back in the oven at 415° F for 25 minutes. The data sheet states 400° F part temperature for 10 minutes. In order to reach that temperature for that time, the wheel had to pre-heat for 15 minutes so it would reach 400° F. Then it remained in the oven for 10 minutes to get the correct cure. I set the oven higher because it would have taken the wheel longer to get to 400° F (30 minutes or longer) if I had set it at 400° F. This because part temperatures climb very, very slowly once their surface temperature is within a few degrees of the air temperature inside the oven.
Here is an example of a header we did with a neon green Illusion system and the same low gloss topcoat.
Many effects can be produced using multi-stage powder coating but the key steps are always:
Proper metal preparation
Correct application technique
Detailed curing plan
Developing a repeatable process
With any coating process you perform as a professional, check for proper cure and adhesion before releasing a part to your customer. Remember, your reputation can be severely damaged by poor quality control and negative reviews can be tough to counter.
One of the most asked questions during my training sessions is,” How do I keep powder from surging out of the gun?”
First, let’s talk about how the two most common types of manual powder guns work and what you should be looking for to prevent powder surges.
Box-Fed Powder Guns
How it works: When you use a box-fed powder gun, you set your box of powder onto the vibrating pad and insert the pick-up tube into the box. The pick-up tube releases a small amount of air near the tip to help fluff the powder so it can be easily transferred to the gun. The pick-up tube works with the vibrating pad to aerate the powder and keep it from clumping together.
What to look for: When properly adjusted, the powder should have a small volcano appearance around the spot where the pick-up tube goes into the box. There should not be enough pressure to shoot powder out of the box, but enough to keep the powder in a loose state and provide a consistent, smooth flow of powder to the powder gun.
Hopper-Fed Powder Guns
How it works: Hopper feed systems typically use a cylindrical stand-alone hopper container that you pour the powder into and close the lid. Air is supplied to the hopper, and the compressed air bubbles up through very small holes in a membrane located at the bottom of the hopper.
What to look for: When properly adjusted, the powder should look like boiling water when you peek in the container. If you stick your fingers into the powder, it should feel like silky smooth baby powder.
It’s possible that not enough compressed air is being supplied to the hopper bottom or the pick-up tube tip. The air supply may have been disconnected or the line may be obstructed, but usually the problem is due to the gun not being properly adjusted.
How to Troubleshoot: There is a small adjustment nut on the side of the unit that regulates the air flow going to the hopper bottom or tube tip. Adjust the nut up and down so that you get the effect described above (boiling water for hopper-fed or small volcano effect for box-fed). Remember, different powders have different densities, so you may have to turn it up a bit when using white primer powders or down a little when spraying something like red gloss topcoat powders.
Also, check your air supply and make sure you have a consistent 60-80 pounds of dry shop air going to the powder unit. If the air pressure is jumping up and down – perhaps because you have multiple pieces of equipment using the same compressor – consider installing a dedicated compressor for your finishing process.
Moisture may be preventing the powder from flowing smoothly. If you have a box-feed system, bringing a fresh box of powder from an air-conditioned storage room to the hot, humid, plant environment can cause problems. You will get humidity condensation on the inside of the box. This makes the powder very difficult to fluff and it won’t be properly picked up by the tube, making it much more likely to surge. You can also have problems if you warehouse your powder in a damp or hot/humid environment (like the corner of the shop). Over time, exposure to moisture will cause the powder to clump up into large chunks.
How to Troubleshoot: First, if you are storing your powder in the shop, move it. Use a clean, air-conditioned storage room to warehouse your powder. Bring a box of powder out about 2 hours before you need it, open the plastic bag, and let it acclimatize to the shop air before using.
3) Water or Oil In The Air Lines
Moisture in your compressed air lines can cause powder to clump. In addition to the problem described above, the situation gets even worse when the air supplied to the gun unit has oil or water in the lines. Since the air is going through the gun and touching the powder, water propelled through the gun will cause the gun to clog, sputter, and surge powder on to your parts. The compressed air can also contaminate the finish by bringing along any oil or contaminants it encounters as it travels through the air lines.
How to Troubleshoot: Be sure to have a good air dryer or a multi-stage air filtration system installed in the system prior to the gun, especially if your air lines usually carry moisture or oil.
4) Worn or Clogged Equipment
Parts of the powder unit can wear down due to the abrasive nature of powder and cause the gun to perform poorly. The first place to check is the venturi nozzle sleeve. This is a plastic sleeve that periodically needs replacement.
How to Troubleshoot: Check the venturi nozzle sleeve to see if the powder has cut grooves into it, or if the orifice has changed from round to oval. If either is true, replace the sleeve.
Powder can also start to stick to wear surfaces in the gun system, especially in hot environments. When powder sticks and hardens, it is due to something known as impact fusion. Normally, compressed air will clean out most areas in the powder unit, but not when impact fusion occurs.
How to Troubleshoot: Q-tips soaked in isopropyl or rubbing alcohol are the best tools for removing powder residue that has partially gelled due to impact fusion.
5) Improper gun settings for the hose or particle size of powder
An improperly adjusted gun can cause surging. Powder gun units have an adjustable ratio of powder to air that is supplied to the gun through the powder hose. If this ratio is off, powder surging can occur.
How to Troubleshoot: The first thing to try is to increase the amount of powder to air, which fill the powder hose and keep continuous powder moving. This will help with intermittent surging. Different powder systems have different adjustments for this, so consult your gun manual or talk to your powder supplier’s technical representative.
Some powders are heavier in density or larger in particle size. For example, white primer is more dense than a red gloss topcoat powder. If you get a big burp of powder when you first trigger the gun after switching colors but no more surging, you may need to reduce the amount of powder to air.
Remember to Maintain Your Change Logs
Every time you make a change to your powder settings, make sure you update your log book. When troubleshooting your process, only change one thing at a time and record the results. This can help you isolate the cause of the problem and more quickly diagnose problems in the future.
Need Any Help?
Reliant offers multiple services to help your finishing operation run smoothly – from troubleshooting to training, installation and more. Call us today.
Outdoor equipment is one of the largest and fastest growing markets for powder coating. This is no surprise, since powder coating outdoor equipmentmakes good sense for both equipment builders and their customers. From playground equipment to sporting goods, powder coated outdoor products last longer and perform better. In this article, we’re going to look at how powder coating systems reduce costs and produce a better outdoor product.
Powder Coating Versus Wet Paint
Almost all metal products that are going outside need to be finished in one way or another. Preventing rust is one of the main reasons that metal coatings were invented. Properly prepared, a finished metal object will outlast an unpainted one. So, why is a powder coating system better than wet paint methods for outdoor equipment? The simple answer is that powder coating is cheaper to apply and typically lasts longer.
Powder Coating Is Cheaper To Apply
A single coat of powder is just as scratch-resistant and durable as a multi-stage wet paint application. Yes, automotive paints can last as long, but those types of wet polyurethane are coatings are expensive and require more steps. First, you have to properly prepare the metal, then prime it, then apply a two-component color coat, and finally apply a clear topcoat. The material cost alone is usually four times that of powder – to get a similar result.
Not only are raw materials cheaper using a powder coating system, but there’s less handling and preparation of the parts! Powder coating is much easier to apply than wet paint. Since powder is simpler to apply, painters will produce fewer flaws, such as sags and runs. They will also need less practice. The average cure time for a metal part is about 20 minutes to bake and 10-15 minutes to cool, so you can typically handle, assemble and pack your parts much faster than when using a wet paint method.
Outdoor Powder Coating Lasts Longer
What about durability benefits in powder coating outdoor equipment? Since rust is usually our primary concern, what kind of resistance to corrosion does powder coating provide and for how long?
Checking For Durability With Salt Spray Testing
Perhaps we want to determine how resistant a coating is to corrosion. We can use a common industry test called Salt Spray Testing. This simulates extreme outdoor conditions by spraying a coated part with pressurized air and saltwater. The salt spray test is used to determine how long a finish might last before rust and corrosion compromise its integrity.
Salt Spray Testing Method
Start with a coated sample part.
Scratch the coating all the way through to the metal in an X pattern.
Blast the part in a testing chamber with 5% or higher salt spray solution.
Time how long you’re spraying.
When rust has reached 1/4″ or more from the scribed point, stop spraying. How much time has elapsed?
Compare this time to other coatings’ times.
Salt Spray Testing results on three coating methods
Avg Salt Spray Hours
1) Grinder, solvent wipe, liquid enamel
2) Grinder, solvent wipe, powder coat
3) Blast, pressure wash, phosphate, powder coat
Here’s some results from different coating processes. The powder coated sample –
with no other preparation or special treatment – lasts on average five times longer than the same object finished with a common wet paint.
Salt spray testing is a controllable lab test that simulates tough conditions to determine overall finish performance when powder coating outdoor equipment. However, many variables will affect true performance. This test gives only a rough estimate of how resilient any finish is. If you use powder coated equipment on the Florida coast, 100 hours could equal one month. But if you are in Arizona 100 hours could equal 15 years. Climate, local weather patterns and equipment usage all play a part in how long your finish will last, but the more salt spray hours your part takes to rust, the better.
Customer Example: Swapping To Powder Coating Can Help Your Outdoor Product Business
Joe’s Trailers is a sample business that wants to provide its customers with durable products. Joe’s Trailers can show how a typical small manufacturing business can easily change its methods to get better results from powder coating outdoor equipment.
Joe’s Trailers started with this wet paint process (Process 1 from the Test Results above)
Grind the welds down and the mill scale off the metal
Wipe the trailer down with acetone
Spray an industrial enamel wet paint
When Joe tested a panel that was coated using this wet paint process, it got these results:
The panel took 50 hours to get 1/4″ creep of rust on the scribed mark
But, Joe sometimes needs to store the trailers outside for a long time. He also sells them in areas where road salts are used. The wet paint finish on the trailers isn’t lasting, and customers complain.
Joe responds to customers’ concerns
Joe decided to purchase a powder coating system to increase quality and reduce material costs. He kept the same preparation. But with his new powder coating oven, he got 250 hours of salt spray before there was a ¼ inch of rust creep with the powder coated finish (Process 2 from Test Results above). This was five times longer than with his wet paint technique. That’s a level of protection so thorough that no trailers rusted in his storage lot while they were stored outside during the off-season.
Joe expands his business to a new kind of customer, increasing profits
Joe got a call from an upscale landscaping company located near Chicago. This customer wanted his trailers to last longer than the current trailers he bought from a local home improvement store. The customer couldn’t use ugly, rusted trailers in his service area because of his demanding clients, and the winter road salt quickly corroded his trailer fleet.
This new piece lasted 1000 hours in the salt spray testing chamber before the rust creep reached 1/4 inch (Process 3 from Test Results above). Because the finish was so durable, Joe was able to offer a four-year rust warranty. He increased his prices to cover labor and equipment. He even got more profit from these upgraded trailers than his basic trailers.
Consider powder coating systems for outdoors products
Switching to a powder coating system can greatly increase coating performance and durability.
Consider it especially for products that must suffer the wear and tear of outdoor use. Products will last longer in outdoor conditions. Business costs like product storage damage, customer returns, and premature warranty issues will be reduced. Finally, higher prices can be charged for better products.
This example has focused on trailers. Remember that these benefits apply to any outdoor product, here’s some ideas to get your creative ideas flowing:
Handrails, fences, and playground equipment.
Automotive parts like truck accessories, and farming machinery
Seasonal items like fishing and marine equipment, deer stands, and much, much more.
When taking on a new powder coating project, remember to ask your customer what they need. Get the correct coating procedure in place to meet their expectations. Use your vendors as resources to help you tailor your powder coating equipment, powder, and pretreatment methods to exceed your customers’ needs.
Reliant Finishing Systems provides fully integrated powder coating equipment. Whether you want to supplement your existing system, or install a complete finishing line, feel free to call us today about any of the following: