Frequently Asked Questions

Metal Coaters FAQ:

The following is a list of frequently asked questions from customers regarding coil coating technology. These questions and answers were obtained with permission from the National Coil Coating Association.

1Q: What are the costs of an in-house spray operation?
A: There are numerous primary, secondary and hidden costs. Primary costs are materials, people, energy, water and the cost of compliance. Secondary costs are the cost of rework, the time involved in manufacturing the product, the number of manufacturing steps appropriate to produce a product in a spray operation, and, of course, touch-ups. Hidden costs include lack of flexibility, since you can only apply one coat at a time, growth limitations and slower manufacturing cycle time due to a paint line bottleneck.
2Q: Why consider prepaint?
A: There are many reasons to outsource your paint operation.
  • Reduce costs
  • Reduce capital outlay
  • Reduce environmental
  • compliance expenses
  • Improve quality
  • Minimize hassles
  • Simplify your life
3Q: Why is outsourcing the best option?
A: In today's business environment, the ability to increase profits through increased prices is nearly impossible. Business analysts say the best way to increase profits is to outsource services or lower internal operating costs. With over 30% of the manufacturing maintenance budgets and plant capital expenditures being spent on growing environmental compliance with ever more strict EPA regulations, the need to reduce these and other operations costs is paramount to survival. Coil coating, also referred to as prepaint, is the outsourcing solution.
4Q: Who should consider prepaint?
A: Any business that works with sheet metal that is fabricated into parts or products that are post painted either for decorative or corrosion protection purposes;
Any business considering updating or replacing its paint line;
Any manufacturing operation that suffers production bottlenecks due to painting operations;
Any company that is constrained by space or capital;
5Q: When should a conversion to prepaint be considered?
A: Generally, conversions to prepaint occur when other major manufacturing changes are taking place. The time to consider a conversion is when:
  • Costs must be lowered to remain competitive
  • The down-sizing and or combining of plants is taking place
  • A strategy of outsourcing is being pursued
  • Plant capacity must be increased
  • Other factors for consideration include:
  • Major capital improvements are planned such as new painting or waste treatment equipment.
  • Compliance with United States Environmental Protection
  • Agency (US EPA) regulations has become an issue of critical concern.
  • New product model(s) are being designed.
  • A plan to optimize use of limited plant floor space is being implemented. New fabricating or material handling equipment is being evaluated.
6Q: How does the coil coating process work?
A: Coil coating is a continuous and highly automated process for coating metal before fabrication. In one continuous process, a coil of metal, up to 72 inches wide moving up to 700 feet per minute, is unwound and both the top and bottom sides are cleaned, chemically treated, primed, oven cured, top coated, oven cured again, rewound and packaged for shipment. More specifically, bare coils of metal are placed on an unwinder or decoiler where the metal is observed for defects. The metal is then cleaned and chemically treated in preparation for painting. Brushes can be used to physically remove contaminants from the sheet, or the metal may be abraded by flap sanders to further enhance the surface. Pretreatments may be used to provide the bond between the metal and the coating, in addition to making the product corrosion resistant. The type of chemical treatment varies with the type of metal being used. After drying, the strip enters a coating room for a coat of primer usually on both sides of the sheet. The pickup roll transfers the coating liquid from the pan to the applicator roll. The liquid is then pumped into the pan, and then overflows back to the supply reservoir, where it is remixed and filtered. The direction of the rotation of the applicator roll plays a part in determining the type of coating. Reverse roller coating, when the applicator roll turns in the opposite direction of the strip, is used to apply thick coatings. Direct roller coating, turning in the same direction as the strip, is used for thinner coatings, 0.5 mils or less. The paint sheet then enters an oven in which the coating is cured at high temperatures for 15 to 30 seconds. The strip exits the oven and is cooled with air and water. A majority of specifications call for two coats (primer and top coat) on each side of the sheet, requiring a pass through a second coater room and oven. The fully painted sheet then exits the second oven and is cooled before inspection and rewind. Since the process allows metals to be finished in one continuous pass, there is flexibility in how the metal is coated and the types of coatings. Organics and inorganics, such as polyesters, epoxies, vinyls, plastisols, acrylics, water-born emulsions, fluorocarbons, dry lubricants, treatment and primer combinations, can be applied. Prepainted coils can also be printed, striped and embossed to create special visual effects. Coil coating provides for controls that are virtually impossible to attain with most other painting processes. Dealing with a flat sheet allows for mechanical cleaning in addition to the spray cleaning. The flat sheet also enables excellent control of coating weights of both the pretreatment and the paint to within a tenth of a mil or less, depending upon the equipment and the paint system being applied. Such advantages, along with the economic and environmental benefits, make coil coating the right choice for many manufacturers.
7Q: What colors are available?
A: There are wide varieties of paints available: polyesters, polyurethanes, zinc-rich coatings, epoxies, fluorocarbons, silicone polyesters and more. A wide range of colors and glosses are available to meet customer needs.
8Q: How do you control the color match from batch to batch?
A: The color control from coil to coil and run to run is one of the distinct advantages of the coil coating process. Metal is coated in the flat, and because of the roll coating process, it is possible to lay down a smooth and uniform film. Laboratories and paint companies that supply coatings have developed ways to maintain film control at a variety of thicknesses that are very reproducible. Line results are very consistent, and coaters have the ability to coordinate lab conditions with line conditions to control the incoming raw materials for consistency.
9Q: Can prepainted metal be formed?
A: Yes, in fact, prepainted metal can be formed and shaped with a finish that is actually superior to post-paint. This is because post-painted surfaces often suffer from dirt and oil residue, uneven application, and other imperfections. You can pre-clean, pre-prime, pretreat, and prepaint metal coils prior to manufacturing, saving cost, time, and hassles, while ensuring a beautiful and flawless surface…even after forming. Once you see how easily prepainted metal can be formed, you'll form a new opinion about this remarkable process.
10Q: Will Prepaint scratch during forming?
A: Sound manufacturing practices, including proper handling, make Prepainted metal no more susceptible to damage than finished products. It is recommended, however, that tooling be dedicated to Prepaint. The use of bare and Prepainted material on the same tools can cause scratching of the Prepainted metal. There are many proven, simple techniques that can be employed to prevent damage, should it occur. Again, refer to NCCA’s “Receiving Prepainted Metal Into Your Plant” document. The on-line tutorial, How to Form Prepainted Metal also provides helpful information on forming and can be viewed on NCCA’s web site
11Q: How can prepainted metal be joined?
A: Prepainted metal can be joined easily – using adhesives, fasteners, or welding – and still retain a beautiful and flawless surface than post-painted metal. That's because prepainted metal has a more flawless top coat to start, with paint covering edge to edge, at a consistent thickness, often with both top and bottom coats. Be assured prepainted metal can be joined beautifully. The on-line tutorial, How to Join Prepainted Metal also provides helpful information on fastening and can be viewed on NCCA’s web site
12Q: Does prepainted metal with cut-edge weather well?
A: Yes, research has proven that prepainted cut-edge actually holds up better over time than post-painted surfaces, due to prepaint's overall superior surface. It may be hard to believe, but it's true: prepainted metal with cut-edges corrodes significantly less than post-painted metal with no exposed edges. So make your products a cut above the rest…by using prepaint. The NCCA, with the help of PPG Industries, Inc. and the North American Zinc-Aluminum Coaters Association (NamZAC), compared the corrosion resistance of prepainted with three types of post-paint. Prepainted metal louvers with exposed cut edges were tested in the field alongside three sets of metal louvers, one with a post-painted electrocoat, a second with a powder finish and a third with a spray finish. The parts were made of hot dipped galvanized steel, and the louvers were exposed to the same environment over time in Daytona Beach, Florida. After 16 months, 44 months, and 68 months of exposure to the elements, comparisons showed the corrosion resistance of the prepainted parts was repeatedly and significantly better than the post-painted parts, in terms of the uniformity of treatment and film thickness. The reason the prepainted parts outperformed post-painted ones is that prepainted metal sheet is uniformly cleaned, pretreated and painted as a flat surface, so the edge to edge and side to side variability is virtually eliminated. In addition, the prepainted part has two coats (primer and top coat), and each is tightly bonded to the metal as compared to a post-painted part, which generally has only one coat of paint. In most cases, the prepainted part has paint (one or two coats) on the backside as compared to the post-painted part which at best has a minimal amount of overspray. Uniform pretreatment and paint on the backside of a part increases the corrosion resistance of the part, enhancing long-term durability. So when it comes to cut-edge, prepaint edges out the competition.
13Q: Can prepainted metal be handled without harming the surface?
A: See if you can handle this fact. Prepainted metal can be shipped on flatbed trucks, moved using forklifts, stored as coils for long periods -- and still retain a beautiful and flawless surface. Hard to believe? It's true: prepainted metal can be handled successfully, without harming the surface. Storing prepainted coils also is a simple process. Coils should be stored in a temperature controlled warehouse. To further ensure successful job site storage, paper-wrap panel bundles, and consider using cover (waster) sheets and end caps. Of course, as an additional prevention, minimize storage time. The contents of each bundle should be described in an external packing slip to minimize damage to paper packaging required for receipt inspection. Generic labels may also be affixed to panel bundles describing proper handling and storage practices. Handling prepainted coils is simple…and it has beautiful results.
14Q: Can prepainting accommodate special design and aesthetic needs?
A: Yes, prepainted coils can be printed, striped and embossed to create special visual effects. In many ways, coil coating has limitless design possibilities, many of which are virtually impossible with post-painted metal.
15Q: How does the process affect floor space and throughput?
A: When you eliminate a post-finishing operation, you free up floor space. Additionally, since work-in-process inventory is reduced, the demands for additional floor space are correspondingly reduced. Production capabilities can grow without adding exclusive manufacturing space.
16Q: What equipment changes are necessary?
A: Minor changes may be required in order to get the most value out of a conversion to Prepaint. The most common changes are die clearances, depending on the product being made. If it is a brake press product, dies might need to be adjusted to allow for the additional film that exists with paint on both sides of the product. It’s also a good time to evaluate potential manufacturing process changes, such as steps that can be eliminated and where time and money can be saved moving a product through the manufacturing cycle faster when utilizing Prepaint.
17Q: Do I have to change my current tooling?
A: In most cases, you don’t have to change tooling but you may have to make a few adjustments. Dies should be polished and die clearances adjusted to fit Prepainted metal. Prepaint serves as a lubricant, and when you use Prepaint, you actually get extended tool life. It is recommended that tooling be devoted only to Prepainted material versus moving back and forth between bare material and Prepainted materials. If the customer processes bare metal, the raw material has not been cleaned and carries roll oils and metal fines. Therefore, it is not wise to move bare material and Prepaint on the same equipment.
18Q: How long does it take to convert to a Prepaint system?
A: The majority of time is spent developing and understanding the requirements of the painted product. Once the requirements are fully understood and agreed to by all members of the team (which should include the metal supplier, coater, paint supplier and key customer representatives), a small trial run is done to confirm that the system, which includes the metal, paint and treatment, meets customer requirements. Once the qualification process is complete, the conversion to Prepaint can take place, and the current paint system can be eliminated. Depending on requirements, this transition can last anywhere from 60 days to one year.
19Q: Are there cost benefits to switching to prepaint?
A: Like most manufacturers, you're probably burdened with adapting your paint shop to changing environmental standards, stringent health regulations, and skyrocketing overhead. Outsourcing your metal treatment and coating operations can even eliminate all of these hassles and costs. All businesses are trying to lower costs and remain competitive. Conversion to prepaint is the answer for manufacturers seeking ways to pare down unnecessary costs. A Prepaint Conversion Team, consisting of internal and external managers and suppliers, should be established to analyze your products and process, to determine if prepaint conversion is practical. This team can also act as a steering committee once implementation begins. After the initial analysis has determined that the use of prepaint is practical, a cost justification study should be conducted to determine the full economic impact of the proposed conversion. This analysis should answer three major questions: What additional costs will be incurred by converting to prepaint? What is the offsetting cost savings from eliminating post-paint? What is the bottom-line benefit of converting to prepainted metal? Once the conversion process is complete, your plant will run more efficiently, more effectively, and more economically. Improve your product. Improve your bottom line. Coil coating is your solution. To learn more about cost savings download our Cost Comparison Form, as well as our PDF on How To Save With Prepaint.
20Q: How do I make the change from post-paint to prepaint?
A: Metal Coaters specializes in the conversion of manufacturers from their inefficient post-painted processes, to the use of highly efficient and environmentally friendly prepainted metal. When this opportunity arises, a dedicated supply chain team is created to identify the customers’ needs and to engineer coating systems that meet their specific requirements.
21Q: What is the minimum quantity I have to order?
A: Typically, truckload orders or truckload quantities would best fit the bill. However, Prepainted metal can be produced to any size order. The larger the order, the lower the cost per ton.
22Q: Can I depend on supply?
A: Yes. Metal Coaters takes the necessary steps to meet the ever-growing demand for Prepainted metal by using and providing access to an Electronic Data Interchange (EDI) and CoilTracker, an internet-based inventory management information system that allows customers to easily manage their unique prepainted steel requirements.