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Powder Coating Q&A: What Should I Watch Out For On An Older Curing Oven?

Every month, we take a question about powder coating and get an answer from our resident coating expert, Bruce Chirrey. If you have a question for Bruce, please send it to info@reliantfinishingsystems.com. This month’s question is about what to look out for on older equipment.

Question:  On a powder coating oven that is well over 10 years old, do the wires go bad and does the oven need to be rewired? What other issues do I need to look out for?

Answer: Oven wiring doesn’t automatically go bad but there is wear and tear on an oven that can cause issues if it has been moth-balled for some time. As with all older appliances, a certified electrician should check for potential code issues and make sure it is safe to operate. This is especially important regarding safety devices such as airflow switches and high temperature limit safeties. Cleaning the motors and making sure they have appropriate amp draws is also important.

The next issue that we see in older ovens is the temperature probes could have been damaged or the connections and/or wiring have developed issues. If the oven does not hold a consistent temperature or tends to shut down due to the high limit being reached, probe replacement or wiring repair might be needed. The signal strength is quite low compared to the wires connected to the motors or other controls, so even a slight bit of damage to the wiring or a loose connection can cause problems.

One of the main things we see if an older oven is put back in service, either after having been decommissioned for an extended period of time or sold to a new owner as used equipment, is the deterioration of the insulation, especially if the oven has ever been moved. You can tell if an oven has degraded insulation if the outside walls get too hot to touch, especially at the tops of the wall panels where they meet the roof. During handling, mineral wool insulation (especially if it has gotten wet due to exposure to moisture or from the inside surfaces of the panels “sweating” and having condensation issues) can break down and settle. The most obvious area of concern is at the top of the panels, which may no longer have insulation inside because it has shifted down during settling.

On belt-driven exhaust and supply fans, you should check to make sure the belts are in good shape, properly aligned, and properly tensioned. Avoid over-tightening the belts to help prevent bearing wear!

Older ovens also tend to have issues with the burner section of their heat units. The burner may have been damaged through handling or from extensive operation, especially at higher temperatures. It is important to check the plumbing connections at the burner’s gas train and to visually inspect the area where the flame is discharged into the heat unit’s airstream. It is not uncommon for the orifice, blossom, or combustion area to be degraded or distorted by heat over time.

Once the wiring, belts, gas plumbing, and burner have been checked, I would then have an oven or paint booth technician come in to test the temperature of the oven. By running an oven recorder, such as a DataPaq, the technician can ensure the oven is operating at the correct temperature and is working as intended.

For further reading, please check out our Buying Used versus New Equipment Guide, which covers some of the other issues you may run into when using an older piece of machinery.

Thanks again, Bruce! Mr. Chirrey and our other systems specialists are always happy to answer your questions and direct you to a solution for your coating needsContact us today!

If you are looking for more powder coating information – including tips and tricks, troubleshooting guides, and equipment maintenance schedules – check out our Resources page.

Cleaning & Pretreatment Primer Part Two: Meeting Standards

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

or

  • 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

or

  • 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. 

Pretreatment Disposal

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

  1. Don’t dump the waste into a lake, pond, river, creek, or other water source!
  2. Don’t dump the waste down a storm drain!
  3. Don’t dump the waste into a ditch or onto the ground!
  4. Don’t dump the waste into your septic tank!
  5. Don’t flush the waste down the toilet!

DO

  1. 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.
  2. Do check with your chemical supplier to get suggestions on the best way to dispose of the waste created.
  3. Do contact a local industrial plumber. He may have some good suggestions from other companies he has worked with in the area.
  4. 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.
  5. 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.

Powder Spray Gun Maintenance Manual & Common Replacement Parts

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.

Text Box:

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.

Venturi Sleeve

Manufacturer & Model Description Part #
Wagner Sprint X Annular Gap Collector Nozzle 241225
Gema Optiflex 2 Insert Sleeve 1006 485
Nordson Encore XT Throat 1095910

Hoses

Manufacturer & Model Description Part #
Wagner Sprint X Powder Hose 11mm 2307502
Gema Optiflex 2 Hose, Antistatic, 10mm 1001673
Norson Encore XT 11mm Powder Hose 768176

Hose Connectors to Gun

Manufacturer & Model Description Part #
Wagner Sprint X Hose Take Up, D10-12, Complete 2322761
  O-ring 9971364
Gema Optiflex 2 10mm Hose Connection 1002 030
Norson Encore XT Kit, Hose Adapter 1106 200
  O-ring 940157

Hose Connectors to Pump

Manufacturer & Model Description Part #
Wagner Sprint X Conductive Nozzle 241476
  Union Nut 241466
  Sealing Ring, Conductive 9974023
Gema Optiflex 2 Hose Connection 1006 531
  Threaded Sleeve 1006 483
Norson Encore XT Throat Holder 1095898
  Nut, Pump 1095914

Gun Tips

Manufacturer & Model Description Part #
Wagner Sprint X Fan Spray Nozzle, Complete 2321976
Gema Optiflex 2 Flat Jet Nozzle NF20-1007934
  Threaded Sleeve 1007229
Norson Encore XT Nozzle, Flat Spray 1081658
  Nut, Nozzle 1081638

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.

Powder Coating Q&A: How Do I Achieve a Thick Powder Coating on Fences & Outdoor Applications?

Every month, we take a common question about powder coating and get an answer from our resident coating expert, Bruce Chirrey. If you have a question for Bruce, please send it to info@reliantfinishingsystems.com.

Question: How do I achieve a very thick coating on fence components that will be used outdoors in all types of weather?

Answer: There are two routes you can go to achieve a thick film coating. The first is to use a PVC powder coating. For a protective PVC coating, a primer must be applied first. If not, the PVC won’t adhere properly. When this happens, the coating can be peeled away from the metal part. After you apply the primer, the PVC powder is applied to a hot part until the desired mil thickness (usually 8-25 mils) is reached. The part is then reheated (typically to about 300°F) to achieve good flow over the entire surface. This PVC coating is not actually cured, as it is only melted enough to cover the part. It does not have the same characteristics as a fully cross-linked coating. The final coating is corrosion resistant, but not very tough. It won’t have good durability because it can be easily scratched and dented. This type of application isn’t recommended for high heat environments since the coating can be reheated and reflowed at higher temps.

The second route is to use a fusion bonded epoxy (FBE) coating. This is probably a better choice for fencing. The parts are heated to 400-450°F and sprayed. The powder is then allowed to cure in place. This technique will typically generate a coated finish that is 8-15 mils thick. The FBE finished part is very corrosion resistant and the finish is quite tough. However, since fence parts are going to be heavily exposed to sunlight, a second coat of polyester powder coating is needed to protect the FBE layer from sunlight degradation. This second coat is usually applied to a hot part that has already been coated with the FBE. After coating the heated part with polyester powder, a little added oven curing time will be necessary. This second coat can also be applied later, after the FBE coating has cured, but you may need to sand the FBE coating to insure good adhesion by the polyester top coat.

Thanks, Bruce! If you need help with your finishing results, please give us a call. Bruce and our other specialists can troubleshoot your process and help you get the best finishes possible. Contact us today.

If you are looking for more powder coating information – including tips and tricks, troubleshooting guides, and equipment maintenance schedules – check out our Resources page.

Customer Spotlight: Prizma

This month we are featuring Prizma, a powder coating and painting company located in Gatineau, Quebec. Prizma prides itself on the impeccable quality of its finishing work. The company works with everything from fencing and rails to custom fabrication and military projects. We got a chance to speak with owner-operator Tyler Connelly, who told us a little bit about Prizma and how their Reliant oven is helping increase their business.

First off, what does Prizma do?

We’re a custom coating job shopwhether it’s rims or railings, or anything from a fabricating shop. We do small to medium sized jobs. 

How did you get started powder coating?

I’ve been in the business for  about 12 years. The company I was working for invested in the equipment, I saw the potential so I started my own.

Is there any specific item that coat do more than anything else?

No, it pretty much changes on a daily or weekly basis.

You have a batch powder coating system?

Correct.

Does the batch system allow you the flexibility you need to handle all these different jobs?

Absolutely, yeah. We tackle a variety of different [metal] thicknesses. That’s where the batch oven works perfectly. 

Why did you decide to purchase equipment from Reliant?

I have another oven that I had purchased before buying Reliant. It was supposed to be considered a Cadillac, if you will, for batch ovens. I paid big bucks for it. Got it installed and there was just headache after headache after headache.

It was constantly down, and it goes down for two weeks at one time. Then it was a disaster just trying to get any service.

When it came time to buy a new oven, I came across Reliant.

It was a lot cheaper than the other company that I was dealing with. And to boot we noticed very quickly that the service was there as well.

Fantastic! That’s what we like to hear. Would you say that the Reliant equipment and the support has helped your business grow?

Most definitely! The other oven that I have – the Cadillac – I would say it’s collecting dust most of the time cause we run everything through the Reliant oven 75 percent of the time. Of course, if we have overflow, we’ll start up the other one. But the day-to-day oven that does the bulk work is the Reliant one.

It sounds like you guys do a lot of throughput on a weekly basis. About how many hours per week is your oven running?

It’s a workhorse. I would say it’s running 16 hours a day, four days a week, at least.

How has the Reliant oven improved your business?

Well, it’s more and more output. I’m not dealing with a lemon that’s shutting down once a week to stop production.

My customers are expecting good quality and a fast turnaround. Being a custom coater – it’s tough because normally when a manufacturing company gets to a certain scale, they’re installing the equipment themselves. If I’m not meeting those requirements, then it makes it that much easier to lose a customer to start it up themselves.

Have you seen customer satisfaction increase since you swapped over to the Reliant equipment?

Most definitely. I don’t have to lie as much anymore.

If someone was going to add powder coating to their shop, what kind of advice would you have for them?

Don’t do it. Ship me your work.

That’s a good answer!

What is one of your favorite things that you shop has ever painted or powder coated?

Honestly that’s a tough one – we paint a lot of interesting stuff. We’re literally all over the map from pieces that give a heads up on earthquakes to internal camera components to airport security scanners. We’ve coated a lot of interesting things.

Is there anything you’d like to add?

Thanks for the support and good product. Your oven keeps me going strong.

Thanks again to Tyler for taking the time to speak with us and to share some of their incredible work! For more about Prizma, find them online at prizma.ca or at their Facebook page, where you can find more samples of their full range of services, including powder coating, liquid paint, sandblasting, pretreatment and more.

Specialty Finishes with Powder Coating

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.

Metal Preparation

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:

  1. The Super Chrome primer cure is higher.
  2. A one-coat system is possible if the metal is shiny to begin with.
  3. A clear topcoat is not required in some series (PPS series).
  4. 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:

  1. Proper metal preparation
  2. Correct application technique
  3. Detailed curing plan
  4. 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.

If you found this article helpful, our articles on outgassing/pinholes and pretreatment may help you troubleshoot your finishes. For even more tips and tricks, equipment guides, and much more, check out our Resources page.

Customer Spotlight: Automated AG

Harvesting equipment from Automated AG, powder coated in Reliant equipment

This months’ Customer Spotlight features Automated AG out of Lake Moses, WA. Family-owned and operated by Kelly and JJ Dagorret, Automated AG specializes in unique and innovative harvesting solutions for the agricultural industry. Automated AG’s decision to bring powder coating in-house has been so successful it launched a new division of the company, Bandit Coatings, which offers powder coating services and is operated by Kelly and JJ’s son, JP Dagorret. We got a chance to speak with Kelly and ask her how Reliant has helped improve her company’s offerings.

Q: Hi, Kelly! First off, can you tell me a little bit about your business and what you do?

A: We’re an OEM equipment manufacturer for the ag industry. We build harvester platforms, various harvest products, watermelon harvesters, bin carriers and trailers – anything really for ag.

Q: How did you guys get started powder coating?

A: Well, we had a vendor who was our powder coat source and we were taking everything to him. In the beginning it was convenient, it was right across the street from our shop. Then we changed location, bought a facility and logistics got in the way, timing got in the way. We thought that it would be huge cost savings to go ahead and purchase our own system, and so we did.

Q: What’s your day to day powder coating process like? What do you do on a daily basis with your products?

A: Everything gets 100% sandblasted and then we rack it, put it in our first oven for our preheat. We have everything on a rail, and once it preheats to the temperature we want it preheated to, we put it in our spray booth, shoot it and then we can roll it back into our preheat oven or roll it forward into our other oven to cook it and cure it, depending on how much product we’re trying to get through the oven in any given day.

Q: So what made you decide to choose Reliant as your powder coating equipment vendor?

A: That would be my husband JJ, he was the one that was doing a lot of the research and looking at different options. Reliant was the best fit for us as far as being able to accommodate oven size. If we needed to go bigger, we can always add-on pieces to make our oven and our system bigger as needed. Everybody we worked with was just amazing. JJ looked into it, I want to say a couple of years ago, and Reliant was who he remembered dealing with.

Q: You guys had originally looked at this a couple years ago and dealing with Reliant was something that you remembered and was one of the factors that brought you back?

A: Yes. I think Kevin was who we dealt with on designing our system and getting everything priced out, getting our estimated delivery date, and then Aaron took over. Everybody that we’ve dealt at Reliant was super friendly, super helpful. Even the guys when they came to install the ovens, it was just a good experience all the way around. And it’s a quality product. JJ did his research, making sure what he was looking at and what we were looking at investing into this to make sure we were getting a good quality product.

Excellent, that’s what we like to hear!

Q: So I think this is going to be a pretty positive question for you: How has Reliant’s equipment and support staff helped your business grow?

A: We are now doing outside [powder coating] work. We originally just purchased this to do our own equipment. We’ve since gotten everything down to where we’re very efficient and so we had time slots available to do outside work. We paid for our system by doing the powder coating 100% ourselves. The system is paid for. [Automated AG installed their powder coating system a little more than 12 months prior to this Customer Spotlight interview.]

Q: So you’ve seen a significant ROI then?

A: Oh yeah. Just the time savings alone and the logistics of transporting all of our product over to a powder coat shop, being able to pick and choose what we wanted to do. If our guys in the shop needed something sooner, we are able to accommodate them and get everything coated whenever they need it. Huge time savings, huge cost savings.

We were spending about twenty four hundred dollars per machine to get it powder coated and now we’re able to do it around three hundred dollars per machine, so huge cost savings. Big numbers when you put out over 100 machines per year.

Q: What advice would you give someone who is looking at powder coating to do their business?

A: Do your homework, make sure you get the oven size that you need and make sure you have room for growth because there’s always an opportunity for expansion for any business.

Q: What’s your biggest success story with your business?

A: Our biggest success story is we’re able to put out quality products in a timely manner. Being able to get a quality control on our own powder coating has helped immensely. We can do a reshoot if we need to, we can do a color change if we need to.

Q: Let me follow up on that – When you talk about your own quality control, how long was it taking you when you had to send it out to someone else versus how much time you’re saving now in-house?

A: We were having turnaround time anywhere from one week to a month. If there was an issue with the coating, by the time we got the product we needed it. It would either be shipping issues, or there were light spots, or there were missed spots – but by the time we got it, we needed it on our assembly line and we had to send the product out.

Now we can catch it. If it comes out of the oven and we see a light spot, we reshoot, throw it back in the oven for a little bit and we’re good to go. If the guys missed a weld, we can tape it off and go ahead and reshoot that area and get the same quality coating as the rest of the machine.

So it’s a huge, huge savings in us being able to do that quality control. Same thing when we do products for other customers. We can make sure that the product we’re sending out is a quality that we stand behind, because everything we do is top quality.

Q: And you were having these quality control and delivery issues even though you said your source was originally just across the street?

A: Yes. He would do a chassis, but there’s wheels, top bars, extensions, various different components included in that chassis. So he would shoot them whenever he had the time or we would call him and say “hey can you run a couple of these for us because we need to start throwing them on a machine.” So we were always chasing components, always chasing parts. Now, we shoot everything in a large batch. And so we’re able to, even with our manufacturing process, create more of the same item, powder coat it, have it sitting on the shelf and ready for our assembly team whenever they need it. We’re not chasing anything anymore.

Q: That’s it from me, is there anything you’d like to add?

A: I will tell you this, any time we do shop tours – we have a lot of visitors from all over the world that come through: local people, growers, producers, what have you for the fruit industry – we always make sure to bring them into our powder coat shop. This is something that we’re very proud of. We always make sure to show people our powder coating.

Thanks again to Kelly Dagorret from Automated AG for taking the time to talk to us. For even more examples of their high-quality work, be sure to check them out on Facebook, on Instagram and at their site, Automatedag.com. If you are looking for powder coating services in and around the Lake Moses, WA are, please contact JP Dagorret at Bandit Coatings.

Powder Coating Gun Application Issues – Powder Surge

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.

(For more information on the differences between manual box-fed and hopper-fed guns, check out my earlier article here.)

Top Five Reasons for Powder Gun Surging

1)  Too Little Air

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.

2) Humidity

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.

Check the venturi nozzle on your powder gun often for wear and replace when needed.

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.

Powder Coating Q&A: Touching Up Your Powder Coated Finish

Every month, we take a common question about powder coating and get an answer from our resident coating expert, Bruce Chirrey. If you have a question for Bruce, please send it to info@reliantfinishingsystems.com.

Question: Occasionally I rub or scratch the fresh powder coated finish off of a small section of a part by accident while working with it after it has been coated. Aside from buying touch up paint to match the color I chose, is it possible to make a spot filler from the powder I was using? Someone I work with suggested using some rubbing alcohol and maybe a spoonful of powder to make a slurry, then applying it with a paintbrush and letting the alcohol evaporate before rebaking. Will this work? Thoughts on this or do you have a better suggestion? The areas I want to fill can be as small as a 1/16” square.

Answer: Touch-up can be tricky with powder coating. The alcohol method can work but might give you an unexpected result. Applying powder to the primary visual surface by any method other than respraying can give a halo-effect, a shimmer, or an uneven surface that may draw attention to the touch-up rather than disguise the original defect.

My simple answer for touch-ups is if it can be recoated, go ahead and recoat the whole part but with much less powder than was applied during the original coating. That way you have a consistency of powder film all the way around the part and no weird surface inconsistencies. If you just put a little powder in a corner, that’s different than on the prime visual area of the part. I have done corner touch-ups with q-tips and small brushes without the alcohol by applying powder to a part after it has been heated, then rebaking it at curing temperature for a few minutes. If you use the alcohol method, make sure the alcohol is completely evaporated. Otherwise, the touch-up and surrounding area can wrinkle.  

Thanks, Bruce! If you’re having issues with your finishing results, please give us a call. Bruce and our other specialists can troubleshoot your process and help you get the best finishes possible. Contact us today.

If you are looking for more powder coating information – including tips and tricks, troubleshooting guides, and equipment maintenance schedules – check out our Resources page.

Essential Powder Coating Supplies by Industry – By Bruce Chirrey

All right. You have decided to start powder coating. For most of you, this is an exciting and scary time. With the purchase of the powder equipment and the arranging of where to put it, you probably haven’t had a lot of time to think about the small stuff. So this article will give you some basic supplies tips that will get you coating faster. There are also so industry specific supplies or requirements to consider, but that will be at the end of the article.

Basic Supplies

Some supplies are fairly self-explanatory. If you are blasting to clean your parts, you will need some sand, garnet, or shot to run through the machine. Don’t buy a lot at first of any specific brand or size because you might wind up switching materials after a week. Buying the minimum amount to test your cleaning process is usually the best idea. The same goes for pretreatment chemicals, if you plan to use them. Most suppliers of chemicals will sell you a small amount to try before you commit to a large order. Sometimes they will even provide small samples for free. It doesn’t hurt to ask for a free sample.

Powder Coated Parts On RackAfter you have decided how to clean your parts, you will need to hang them in order to transport powder coated parts from the powder booth to the oven with out rubbing the powder off. Racks can be purchased or home made depending on your metal fabrication skills. If you are buying or making, the most important part of a rack is the wheels. Make sure you have metal casters at the bottom of the rack, that can withstand 450 degree heat. Order or make enough racks that you have at least one rack per finishing step. One in blasting ready for loading, one in the powder booth, one in the oven, and one in cool down or in your off load area. You don’t need that many to start powder coating and you may want to test one or two rack set-ups before you commit to buying or making four or more.

While you are experimenting with your rack design, try some different hooks. Get some samples from hook manufacturers or make some hooks using some bar stock and a wire/pipe bender. Most manufacturers do not use the first type of hook they try. You want a hook that will not get in the way of the powder, that will support the part, and be conductive for a proper grounding of the part. Plan on replacing or cleaning hooks every 5-6 uses. The reason for that is to keep a good ground on the part so that the powder does not fall off easily when moved or when a draft of air hits a powdered part.

Air cleanliness is very important to powder coating. Make sure you have a good oil/water separator on your incoming air line to make sure the powder is clean before it hits your powder gun and the powder that is being applied to your parts. A dedicated compressor with an air drier is ideal, but a decent filter on your air line will stop moisture from hitting your powder.

Now that you have clean parts on racks, they are ready to be powder coated. Most new powder coaters start with polyester powder coating. Polyester powder is user friendly, durable inside and outside, fairly inexpensive (except for wild colors and effects), and cures in an oven reliably without a lot of fine tuning. All powder companies have standard color cards that you can order from that cover most industry colors. If you know exactly what powder you will be using, then get a weeks worth of production quantity at a time. Most powder companies have 2-3 days shipping times on standard colors.

Powder Coating GunsWhile you are ordering powder, don’t forget to get some extra booth filters. One set of the first layer of filtration should do, be they filter squares or blankets. The other filters like bag or HEPA filters should not wear out very fast and can be ordered when needed. Remember not to “blow out” dirty filters with compressed air. That will cause holes in the filters and allow powder to get to the secondary filters faster than it should. Although the booth will pull most of the powder into the filters, operator masks are still required. According to the Occupational Safety & Health Administration (OSHA), Washington, powder coating workers must wear no less than what is called an “N95,” NIOSH-approved respirator (otherwise known as a dust mask).

Depending on the powder gun you have purchased, there will be different wear parts to keep on hand to keep you gun spraying properly. Powder pump(venturi) nozzles, gun tips, and extra hoses are the most common extra powder coating gun supplies to keep around. The nozzles are near the pick-up tube and are necessary to keep the powder flowing without surging. They are plastic, so powder will eventually wear them out by cutting into the side. If you see a groove being cut into a nozzle or if the nozzle starts to look oval in the middle, change it out. Gun tips typically don’t wear out, but operators do drop guns accidentally so it’s a good idea to have a spare or two. Hoses  can get holes, be run over, get cut, or be melted by a hot rack. I’d have a couple around just in case. Some folks keep an extra set of hoses for color changes.

Blast RoomsWhile you are in the powder booth area, there are a few other things that might be good to have around. Silicone plugs and high temperature tape will keep powder out of areas or off surfaces that you don’t want powder coating on. Bolt holes and friction surfaces are a couple of places you would want to keep powder away from. A box of cheap ear plugs are good to keep in the powder area. Safety-wise it’s a good idea to wear ear plugs in a noisy environment like a spray booth. Unused ear plugs are also great hose scrubbers for using between color changes. By using compressed air, you can shoot an earplug through a powder hose to “scrub” stubborn powder off of the interior hose walls.

Before you start moving racks in and out of the oven, you will want to invest in some high temperature gloves or mitts. 400 degrees F is pretty hot and will burn you if you don’t take precautions. Keep some high temperature grease close to grease the bearings of the fan in the oven.

mek-solution-for-powder-coating-testingAfter your parts have cooled down from being baked, it is a good idea to regularly check your finish to make sure it meets your quality standards. The easiest test is an MEK rub test. By getting some MEK and some q-tips, you can spot check your parts to see if you are getting enough cure. 20 double rubs will let you know if you have enough cure. Adhesion testing is also done fairly easy although you will want to check it on a scrap piece of metal instead of a part. Use a utility knife and some sticky tape to do a cross cut with about 5 cuts each way. Apply the tape to the cross cut and then pull up the tape. If any squares come up you need to look at your metal preparation or your cure. The final tool in a basic quality control box is a dry film thickness gauge. Be sure and get one that will measure steel and aluminum. Checking powder thickness is important for ensuring durability and to reduce unnecessary powder waste.

Those are the basic supplies or additions that every industry should think about incorporating in their process. Next up are some additional supplies or different materials that you might need for specific industries.

Architectural Aluminum

All architectural aluminum finishes will have to be pretreated with a Zirconium based pretreat and something to take off the oxidation of the aluminum. The powder used for extruded aluminum is usually of two different qualities. The first is Superdurable Polyester AAMA 2604 quality. This is what most architects will specify for the exterior of buildings. KYNAR® AAMA 2605 quality is the most durable exterior powder for powder, however, it is very specific on how the pretreatment must be applied. KYNAR® can only be applied over an automatic pretreatment system specially designed for these 10-30 year warranty finishes. Since the warranty is so extensive, an on-site boiling water test is usually added to the quality control daily checks. A color computer or unit is usually required because customers need verification that the parts produced will match other components done at different manufacturers.

Heavy Exterior Equipment

Heavy equipment suppliers usually will need upgraded exterior durable finishes. This starts in the pretreatment. While a one stage pressure wand may work in most cases, there may be additional steps depending on the end customers specifications. 3-5 stage systems may be needed to insure proper salt-spray requirements. A wash stage, rinse stage, phosphate (iron/zirconium/zinc) stage, rinse stage, and sealer stage is a common set-up. Additional testing like impact or salt spray are usually done on-site or by the powder suppliers lab.

Pipe

Powder coating industrial pipe is an interesting process since they usually heat the pipe to curing temperature and then spray or dip the pipe with powder. This uses a specific kind of powder called Fusion Bonded Epoxy powder. Since the pipe goes underground, the epoxy gives the best durability versus rust, chemicals, and moisture. However, if the pipe is exposed to the sun, polyester powder will have to be applied over the epoxy to keep the coating from degrading due to the UV rays.

Marine Equipment

Marine equipment like cranes on ships are the toughest environments for any coating to survive. Daily exposure to salt water and extreme temperature changes can wreck any finish. The pretreatment will have to be a 5-7 stage zinc phosphate system followed by a zinc-rich epoxy powder primer. Then a urethane topcoat will be applied to allow the best flexibility and UV resistance protection available. This is not a cheap system and will need regular salt spray and QUV testing by the manufacturer or their powder supplier.

Automotive

Automotive part manufacturers are usually grouped into under-hood part and exterior part suppliers. Under-hood parts are usually coated with epoxy powder due to the great chemical resistance epoxy provides. Since chemical resistance is so important, regular watch glass checks with hydraulic and brake fluid are not uncommon. Exterior parts are usually urethane or superdurable polyester powder. Gloss and color are very important for automotive manufacturers so daily gloss checks with a gloss meter and color checks from a color unit are usually required. Flexibility and dent resistance is also checked by having impact drop testing and a conical mandrel bend test.

Military

Military powder coating is fairly new. They have a two coat system usually starting with an epoxy powder primer and a CARC powder topcoat. CARC stands for chemical agent resistant coating. It is designed to be resistant to chemical warfare chemicals and also aids in the decontamination process if the vehicle is exposed. All the parts need to be pretreated with zirconium. A gloss meter is usually required to make sure the low gloss is within standard.

Summary

Developing your supplies list to tie into your powder process. Don’t be afraid to try different suppliers or qualities of each item. All of your supplies should contribute to a more efficient process and a quality finish. Try and compare each item apples to apples to see how much use you get out of it and if it helps your end customer. Keeping good notes on when you used an item and how much life you really got out of a particular spare part will guide you on keeping costs low and quality high.