Bottom-Line Benefits of Using Prepainted, Coil Coated Metal

Coil coating is one of the most advanced, efficient and environmentally friendly means of coating metal. Using prepainted metal can provide manufacturers with a streamlined manufacturing process, cost savings and a more environmentally friendly plant.

In the old days of traditional manufacturing, steel and other metals arrived at factories in a raw, untreated, unpainted state. Companies would fabricate and paint or treat the metal components of their product at the plant. This was a costly, time-consuming and environmentally harmful practice. The coil coating process was pioneered in the s for painting, coating and pretreating large coils of metals before they ever arrived at a manufacturing facility. The Venetian blind industry was the first to discover the benefits of prepainted metal.

Today, more than 800 million tons of coil coated steel and aluminum are produced and shipped in North America alone each year. Industry leaders using coil coated metal include GE, Whirlpool, Trane, Mercedes Benz, Nordyne and Steelcase, to name just a few. Thousands of products in dozens of different industries are made more efficiently with prepainted metal.

Major industries include building products such as metal roofs, wall panels and garage doors; office furniture (desks, cubical divider panels, file cabinets and modular cabinets); home appliances (refrigerators, dishwashers, freezers, range hoods and microwave ovens); heating and air-conditioning outer panels and ductwork; commercial appliances; vending machines; foodservice equipment and cooking tins; beverage cans; automotive panels and parts (fuel tanks, body panels and bumpers); and other components. New applications make the switch every year.

The Coil Coating Process

Coil coating is one of the most advanced, efficient and environmentally friendly means of coating metal. Large coils of metal (including cold-rolled steel, hot dip galvanized, electro galvanized, zinc-steel, aluminum, stainless steel, copper and brass) can be coated in a continuous, highly automated process prior to fabrication. During this continuous process, the metal is unwound and then cleaned and chemically treated. Depending on the product specifications, one or both sides may then be primed and/or topcoated, oven cured, and rewound for shipment.

The variety of coatings available is almost unlimited and includes polyesters, polyurethanes, epoxies, vinyls, plastisols, acrylics, waterborne emulsions, zinc-rich coatings, fluorocarbons, dry lubricants, and treatment and primer combinations. Moreover, product quality is continually improving as a result of new industry-specific coatings that are regularly coming to market and advanced testing performed throughout the coil coating process.

Superior Quality Control

The prepainting process is designed to produce highly uniform, impeccable-quality coatings. The coatings are precisely applied with special equipment that provides a high-quality finish. The coatings can be on both sides of the metal and meet the finished product specifications. Manufacturers using prefinished metals will find consistent color, texture, thickness and performance in their finished products.

To ensure the best possible results, numerous quality control tests are performed during the coil coating process. For example, before coating, the metal substrate and the viscosity, color, gloss and physical performance of the paints are tested. As the uncoiled metal is coated, the surface treatment process is tested and adjusted continuously to ensure a high-quality finish. In addition, the paint thickness, curing temperature and production line speed are controlled and measured. Coating performance, including features like gloss, color, hardness, adhesion, and resistance to cracking and marring, are inspected as the coated parts leave the production line. After production, parts are tested for corrosion resistance with salt, chemical sprays and/or water immersion. Additionally, they&#;re examined for heat resistance, accelerated ultraviolet and environmental exposure. Other tests conducted on coil coated parts include stain-resistance, welding capability, and resistance to abrasion.

Prepainted parts can outperform post-painted applications because prepainted metal coils are uniformly cleaned, pretreated and painted as a flat surface. The primer coat also prevents the undercutting of paint and enhances corrosion resistance, the durability of the product and overall quality. Furthermore, the coatings are tightly bonded to the metal and often are applied to both sides of the metal.

Moreover, there is almost an unlimited selection of available prepaint coatings. These coatings are available in various degrees of gloss, color, textures, lubricity, flexibility and combinations thereof. Various primers can be selected to help create an industry-specific coating system that maximizes the performance of the product for special end-use applications.

Case in Point

For a manufacturer using painted steel, aluminum or other metals in the manufacturing process, the process of coil coating can dramatically improve productivity, reduce processing costs, improve quality, and reduce inventory and environmental/emission concerns, all at the same time. Just ask Trane, Inc., a manufacturer of commercial air handlers. Quality has always been a top priority for the company, and this led to the switch from post-painted metal to coil coating technology.

Several products at the Trane facility in Cullen, LA, are currently being produced using a new prepainted FAS-NER from AKH Inc., with prepainted metal. The fastener system is a simple punch and die operation, which automatically feeds, punches, inserts and locks a self-piercing fastener to produce a solid joint in one high-cycle operation. The fastener is inserted directly into prepainted metal without the need for pre-punched holes. This feature saves time and labor costs associated with tooling maintenance.

In the past, the Trane air handlers were spot-welded and then post-painted. Now, the products are completely assembled with prepainted metal. Since converting, Trane has seen an increase in productivity and profitability. Trane reports they have also experienced more consistency in the strength of the joint, as well as a better product appearance.

Several major appliance manufacturers also have experienced the benefits of using the combination of the AKH FAS-NER and prepainted metal. The fastener color is matched to the color of the finished product, allowing for the elimination of post-paint operations.

Numerous Benefits

The benefits of prepainted metal are many. It can be used for most product applications and will provide manufacturers with a streamlined manufacturing process, cost savings and a more environmentally friendly plant.

For more information about prepainted metal, call 216.241. or visit

**************

SIDEBAR: 5 Misconceptions about Coil Coating

Although the prepainted metal process has been around for years, a few misconceptions about the process still exist.

1. Myth: Outsourcing your painting operations would be an added cost.

Fact:

Like most manufacturers, companies are often burdened with adapting their paint shop to changing environmental standards, strict health regulations and increasing overhead. Businesses are trying to lower costs and remain competitive. Outsourcing the metal treatment and coating operations can alleviate or even eliminate these costs.

One recommendation is to establish a prepaint conversion team, consisting of internal and external managers and suppliers, to analyze the 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 determines 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, the plant will run more efficiently, more effectively and more economically. Switching to prepainted metal can improve your product and your bottom line.

2. Myth: Prepainted metal cannot be formed.

Fact:

Coil coated metal can be formed without any loss in surface quality or appearance. In fact, the paint system can be designed to have greater flexibility than the metal and can be 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. After the metal has been precleaned, preprimed, pretreated and prepainted, it can be formed. The paint layer is often more flexible than the underlying metal substrate.

3. Myth: Prepainted metal with cut-edge doesn&#;t weather well.

Fact:

Some manufacturers are concerned with exposed cut-edge on prepainted metal, but research has shown that prepainted cut-edge actually holds up better over time than post-painted surfaces. The National Coil Coating Association (NCCA), with the help of PPG Industries, Inc. and the North American Zinc-Aluminum Coaters Association (NamZAC), compared the corrosion resistance of prepainted cut-edge 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, FL. After 16 months, 44 months and 68 months of exposure to the elements, comparisons showed that the corrosion resistance of the prepainted parts was repeatedly and significantly better than the post-painted parts.

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 topcoat), 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; in comparison, post-painted parts at best have 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.

4. Myth: Coil coated metal cannot be joined without aesthetic and performance problems.

Fact:

More and more manufacturers are realizing that precoated metal can be joined easily - using adhesives, a variety of mechanical assemblies with or without fasteners, or even welding - and still retain a more beautiful and flawless surface than post-painted metal.

Using adhesives as a joining method offers a variety of benefits such as smooth surfaces, clean contours and uniform stress distribution. Adhesives also seal joints away from the elements. Mechanical assembly works well with prepainted metals, both with and without fasteners. Nuts, bolts and screws are cost-effective fasteners that offer design flexibility and allow for parts to be disassembled. Using rivets offers excellent shear and tensile strength as a fastener. Prepainted metals can also be assembled without fasteners by using a variety of methods, including lock and seam, pierce and tab, or stake and clinching methods. Welding is also an option for joining prepainted metals. Working closely with a coil coater can make welding an attractive joining option.

For more information about prepainted metal, call 216.241. or visit www.coilcoatinginstitute.org

5. Myth: You can&#;t handle coil-coated metal without marring the surface.

Fact: Precoated metal can be shipped on flatbed trucks, moved using forklifts, stored as coils for long periods - and still retain a more beautiful and flawless surface than post-painted metal. Prepainted metal can be handled successfully without harming the surface.

Source: NCCA


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SIDEBAR: 10 Signs a Manufacturer Should Consider Prepainted Metal

Converting from in-house post-painted metal to outsourced prepainted metal can save manufacturers money and time, and can ensure that products are the highest possible quality. The most important issues to consider when converting to a prepaint operation are timing, capital outlay, manufacturing costs and environmental compliance. Following are 10 indicators that a manufacturer should consider using prepainted steel or aluminum:

1. In-house paint shop expenses are on the rise. When maintenance budgets are growing and capital investments are required to comply with strict EPA regulations, prepainted metal and aluminum is often a cost-effective alternative to in-house paint lines. Many hidden costs are associated with in-house spray or powder operations. Staffing with trained personnel, equipment, supplies and even environmental compliance all contribute to the expenses of owning an in-house paint shop.

2. Internal operating costs need to be lower. Many manufacturers are searching for ways to lower operating costs in order to remain competitive. Through outsourcing prepainted metals, factories can eliminate costly in-house paint operations and the associated expenses of manning the production line. Some of the major cost savings of prepaint conversion include inventory, environment, insurance, cleaning and waste removal, purchasing raw materials, and operating costs.

3. Plant capacity must be increased. By purchasing prepainted metal, plants are actually outsourcing the painting process and can eliminate or greatly reduce the size of in-house paint shops, generating more floor space for other uses.

4. Coating quality needs improvement. Coil coated metals are uniformly cleaned, pretreated, painted and cured as a flat surface, so that the edge-to-edge and side-to-side variability is virtually eliminated. The prepainted part has two coats of paint (unlike powder coating, which has only one) that are bonded tightly to the metal.

5. Downsizing and/or combining plants is taking place. A good time to consider using coil coated metals is when other major manufacturing changes are taking place. Manufacturers can reduce expenses significantly and increase paint quality greatly by outsourcing the painting process. Coil coated metals can be effectively handled, cut with superior corrosion resistance, joined with welding and adhesives, and formed for many uses&#;all with a beautiful finish.

6. New product models are being considered. Many times when design changes are being made, a prepainted metal can be specified and the new design can be more cost-effective to produce.

7. Manufacturing bottlenecks are reducing productivity. Many delays in a plant are caused by paint issues such as stoppage while parts are painted, dried and cured before moving to the next phase of assembly. These bottlenecks can be eliminated with prepainted metal. Prepainted steel and aluminum are uncoiled, cleaned, primed and painted to a manufacturer&#;s specifications and re-coiled prior to shipping to the factory.

8. It&#;s time to update or replace the paint line. Capital expenditures can be avoided and long-term cost savings achieved by choosing prepainted steel and aluminum, rather than refurbishing or replacing a paint line.

9. A strategy of outsourcing is being implemented. Purchasing prepainted metals is a cost-effective outsourcing option that actually improves the durability of the coating.

10. New fabricating or material handling equipment is being evaluated. When significant changes are made at the plant, it creates an opportunity to improve many aspects of the manufacturing process, including the use of prepainted metal.

Source: NCCA

Links

By Bob Martinelli

Applying aftermarket protective coil coatings is critical to sustaining the full lifecycle of newly-installed HVAC equipment destined for corrosive environments, but many engineers and contractors don&#;t specify this important step.

Coastal areas are the most likely target markets for coil coatings. Salt spray from oceans can prematurely corrode outdoor HVAC coils in as little time as a year if not coated before use. Salt spray can travel as far inland as 10 miles, which creates a huge area of vulnerable equipment on North America&#;s seaboard.

What is new today are coatings that have been packaged in game-changing, convenient easy-to-use aerosol cans.

Protecting HVAC equipment with coil coatings isn&#;t a new concept. For many years, HVAC manufacturers have shipped newly-made coils directly to coating specialists as per the specification of engineers and contractors. Sensitive parts, such as electrical components, are masked-off, then coils are sprayed or electro-coated before the unit is shipped and installed in their corrosive environment destination.

What is new today are coatings that have been packaged in game-changing, convenient easy-to-use aerosol cans. Contractors can now coat coils in their shop or onsite before installation. This skips the past time and effort required to send a coil or the entire unit out for factory-applied coatings. Furthermore, contractors can create an entire do-it-yourself (DIY) coating niche that requires minimal experience or training.

Choose a brand that with a long history and reputation for providing OEM-approved, factory applied coil coatings.

When selecting a coil coating it is important to make sure that the product has passed ASTM B117 test standards for salt spray. It also should have multiple marine and industrial ASTM test standard listings for resisting ultraviolet (UV) rays, acid rain, high concentrations of urban vehicle emission air pollutants and other outdoor contaminants. It&#;s also important to choose a brand that with a long history and reputation for providing OEM-approved, factory applied coil coatings.

When To Use A DIY Coating 

Deciding when to use a coating specialist versus a contractor with field-applied DIY aerosol applications, usually depends on the project scope. For example, it&#;s more economical to request the manufacturer ship 200 new split system condensers to a factory-coating specialist if the units are destined for a beachfront condo complex. However, a contractor using DIY aerosol protective coatings for a beachfront home&#;s condenser(s) can be very economical and reduce the installation time versus shipping the product(s) to and from a coating specialist. As for unit size, typically any HVAC coil in a system 10-tons or smaller is perfect DIY coating application.             

While coastal areas play a large part in coil corrosion, other potential areas where premature coil corrosion can occur are:

• Urban areas, and particularly airports, which have heavy concentrations of airborne vehicle emissions;
• Buildings near or located inside properties of waste water treatment plants;
• Any heavy industrial area that emits airborne chemicals;
• Restaurants where cooking grease particulates are exhausted in  close proximity to the HVAC rooftop system.             
• Heat Transfer and Static Pressure Considerations

Many engineers and contractors have questions about how the coatings will effect a coil&#;s heat transfer performance. While some coating formulas might be borrowed from other industries, only coatings designed specifically for HVAC coils  should be used, because they&#;re formulated for negligible heat transfer loss. These specialty coil coatings are typically only 1.4-ml thick or less, versus other thicker industrial coatings that can negatively affect heat transfer.  

Static pressure is also a consideration, but coatings designed specifically for HVAC coils don&#;t increase the pressure drop through the coil. Instead, they may even lower the pressure drop versus an uncoated coil, because less static pressure-increasing contaminants will reside or adhere to the coil surfaces.

Of course, there&#;s more to consider about corrosion than its effect on static pressure. Corrosion, especially from salt, can create formicary and pitting processes that ultimately lead to leaks.

How DIY Coatings Are Applied

Contractors can apply DIY coil coatings in the field, or in their shop. Obviously, shop-applied coatings are preferred, because of the controlled environment for temperature, humidity with no challenges from wind. 

&#;Clean&#; and &#;dry&#; are key to a good coating adhesion. The first step mandates cleaning the coil with a foaming, non-acid, non-caustic coil cleaner and then thoroughly rinsing the coil. Many contractors believe that new coils are clean. However, most new coils have machining oil residue from the manufacturing process that must be fully removed for successful coating adhesion.

While contractor-applied coatings are designed for new units, if an older unit that has already been exposed to corrosion is being coated, it should be treated first with a purposely-formulated salt and oil removing coil cleaner.

Once the coil has been cleaned and is completely dry, the electrical contacts, moving parts, valves, compressors and other parts not to be coated, are masked off with blue painter&#;s tape, which doesn&#;t leave a residue and is easily removed. It might also be beneficial to coat the unit&#;s compressors and accumulator to minimize the corrosive environment&#;s effect on these key components.

The coating stream is sprayed approximately 4-inches away from the coil in similar movements to spray painting. Some coatings are clear, which allow the coil to appear aesthetically uncoated. Other coatings are blue, for when the applicator prefers to visibly track even coverage of the sprayed area. Drying times for touching is 10 minutes; handling is 20 minutes; recoating is 30 minutes; and a full cure typically requires 48 hours.

During use, the corrosive elements in the air will attack the coil&#;s coating instead of the copper and aluminum surfaces. For this reason, coatings may need a re-application every five to 10 years depending on the environment&#;s corrosiveness.

Coatings are essential for coastal areas, however engineers and conrtactors should also consider the prospect of coating coils in high air pollution areas such as urban centers and airports also. In any corrosive situation, coatings will help improve the efficiency of the unit and maximize the unit&#;s useful life.

                                                      
Bob Martinelli is Director of Corporate Development at RectorSeal® LLC, Houston, Texas (www.rectorseal.com). Modine Coatings recently named RectorSeal the master distributor for GulfCoat&#;, a new coil coating packaged in aerosol cans for contractors to apply at their shop or jobsite. GulfCoat extends the lifecyle of coils and HVAC equipment exposed to coastal area salt, urban air pollution and corrosive chemicals. RectorSeal offers hundreds of skus of HVAC tools and accessories that are sold exclusively through HVAC wholesalers. Martinelli can be reached at [ protected]

In the old days of traditional manufacturing, steel and other metals arrived at factories in a raw, untreated, unpainted state. Companies would fabricate and paint or treat the metal components of their product at the plant. This was a costly, time-consuming and environmentally harmful practice. The coil coating process was pioneered in the s for painting, coating and pretreating large coils of metals before they ever arrived at a manufacturing facility. The Venetian blind industry was the first to discover the benefits of prepainted metal.

Today, more than 800 million tons of coil coated steel and aluminum are produced and shipped in North America alone each year. Industry leaders using coil coated metal include GE, Whirlpool, Trane, Mercedes Benz, Nordyne and Steelcase, to name just a few. Thousands of products in dozens of different industries are made more efficiently with prepainted metal.

Major industries include building products such as metal roofs, wall panels and garage doors; office furniture (desks, cubical divider panels, file cabinets and modular cabinets); home appliances (refrigerators, dishwashers, freezers, range hoods and microwave ovens); heating and air-conditioning outer panels and ductwork; commercial appliances; vending machines; foodservice equipment and cooking tins; beverage cans; automotive panels and parts (fuel tanks, body panels and bumpers); and other components. New applications make the switch every year.

The Coil Coating Process

Coil coating is one of the most advanced, efficient and environmentally friendly means of coating metal. Large coils of metal (including cold-rolled steel, hot dip galvanized, electro galvanized, zinc-steel, aluminum, stainless steel, copper and brass) can be coated in a continuous, highly automated process prior to fabrication. During this continuous process, the metal is unwound and then cleaned and chemically treated. Depending on the product specifications, one or both sides may then be primed and/or topcoated, oven cured, and rewound for shipment.

The variety of coatings available is almost unlimited and includes polyesters, polyurethanes, epoxies, vinyls, plastisols, acrylics, waterborne emulsions, zinc-rich coatings, fluorocarbons, dry lubricants, and treatment and primer combinations. Moreover, product quality is continually improving as a result of new industry-specific coatings that are regularly coming to market and advanced testing performed throughout the coil coating process.

Superior Quality Control

The prepainting process is designed to produce highly uniform, impeccable-quality coatings. The coatings are precisely applied with special equipment that provides a high-quality finish. The coatings can be on both sides of the metal and meet the finished product specifications. Manufacturers using prefinished metals will find consistent color, texture, thickness and performance in their finished products.

To ensure the best possible results, numerous quality control tests are performed during the coil coating process. For example, before coating, the metal substrate and the viscosity, color, gloss and physical performance of the paints are tested. As the uncoiled metal is coated, the surface treatment process is tested and adjusted continuously to ensure a high-quality finish. In addition, the paint thickness, curing temperature and production line speed are controlled and measured. Coating performance, including features like gloss, color, hardness, adhesion, and resistance to cracking and marring, are inspected as the coated parts leave the production line. After production, parts are tested for corrosion resistance with salt, chemical sprays and/or water immersion. Additionally, they&#;re examined for heat resistance, accelerated ultraviolet and environmental exposure. Other tests conducted on coil coated parts include stain-resistance, welding capability, and resistance to abrasion.

Prepainted parts can outperform post-painted applications because prepainted metal coils are uniformly cleaned, pretreated and painted as a flat surface. The primer coat also prevents the undercutting of paint and enhances corrosion resistance, the durability of the product and overall quality. Furthermore, the coatings are tightly bonded to the metal and often are applied to both sides of the metal.

Moreover, there is almost an unlimited selection of available prepaint coatings. These coatings are available in various degrees of gloss, color, textures, lubricity, flexibility and combinations thereof. Various primers can be selected to help create an industry-specific coating system that maximizes the performance of the product for special end-use applications.

Case in Point

For a manufacturer using painted steel, aluminum or other metals in the manufacturing process, the process of coil coating can dramatically improve productivity, reduce processing costs, improve quality, and reduce inventory and environmental/emission concerns, all at the same time. Just ask Trane, Inc., a manufacturer of commercial air handlers. Quality has always been a top priority for the company, and this led to the switch from post-painted metal to coil coating technology.

Several products at the Trane facility in Cullen, LA, are currently being produced using a new prepainted FAS-NER from AKH Inc., with prepainted metal. The fastener system is a simple punch and die operation, which automatically feeds, punches, inserts and locks a self-piercing fastener to produce a solid joint in one high-cycle operation. The fastener is inserted directly into prepainted metal without the need for pre-punched holes. This feature saves time and labor costs associated with tooling maintenance.

In the past, the Trane air handlers were spot-welded and then post-painted. Now, the products are completely assembled with prepainted metal. Since converting, Trane has seen an increase in productivity and profitability. Trane reports they have also experienced more consistency in the strength of the joint, as well as a better product appearance.

Several major appliance manufacturers also have experienced the benefits of using the combination of the AKH FAS-NER and prepainted metal. The fastener color is matched to the color of the finished product, allowing for the elimination of post-paint operations.

Numerous Benefits

The benefits of prepainted metal are many. It can be used for most product applications and will provide manufacturers with a streamlined manufacturing process, cost savings and a more environmentally friendly plant.

For more information about prepainted metal, call 216.241. or visit

**************

SIDEBAR: 5 Misconceptions about Coil Coating

Although the prepainted metal process has been around for years, a few misconceptions about the process still exist.

1. Myth: Outsourcing your painting operations would be an added cost.

Fact:

Like most manufacturers, companies are often burdened with adapting their paint shop to changing environmental standards, strict health regulations and increasing overhead. Businesses are trying to lower costs and remain competitive. Outsourcing the metal treatment and coating operations can alleviate or even eliminate these costs.

One recommendation is to establish a prepaint conversion team, consisting of internal and external managers and suppliers, to analyze the 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 determines 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, the plant will run more efficiently, more effectively and more economically. Switching to prepainted metal can improve your product and your bottom line.

2. Myth: Prepainted metal cannot be formed.

Fact:

Coil coated metal can be formed without any loss in surface quality or appearance. In fact, the paint system can be designed to have greater flexibility than the metal and can be 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. After the metal has been precleaned, preprimed, pretreated and prepainted, it can be formed. The paint layer is often more flexible than the underlying metal substrate.

3. Myth: Prepainted metal with cut-edge doesn&#;t weather well.

Fact:

Some manufacturers are concerned with exposed cut-edge on prepainted metal, but research has shown that prepainted cut-edge actually holds up better over time than post-painted surfaces. The National Coil Coating Association (NCCA), with the help of PPG Industries, Inc. and the North American Zinc-Aluminum Coaters Association (NamZAC), compared the corrosion resistance of prepainted cut-edge 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, FL. After 16 months, 44 months and 68 months of exposure to the elements, comparisons showed that the corrosion resistance of the prepainted parts was repeatedly and significantly better than the post-painted parts.

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 topcoat), 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; in comparison, post-painted parts at best have 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.

4. Myth: Coil coated metal cannot be joined without aesthetic and performance problems.

Fact:

More and more manufacturers are realizing that precoated metal can be joined easily - using adhesives, a variety of mechanical assemblies with or without fasteners, or even welding - and still retain a more beautiful and flawless surface than post-painted metal.

Using adhesives as a joining method offers a variety of benefits such as smooth surfaces, clean contours and uniform stress distribution. Adhesives also seal joints away from the elements. Mechanical assembly works well with prepainted metals, both with and without fasteners. Nuts, bolts and screws are cost-effective fasteners that offer design flexibility and allow for parts to be disassembled. Using rivets offers excellent shear and tensile strength as a fastener. Prepainted metals can also be assembled without fasteners by using a variety of methods, including lock and seam, pierce and tab, or stake and clinching methods. Welding is also an option for joining prepainted metals. Working closely with a coil coater can make welding an attractive joining option.

For more information about prepainted metal, call 216.241. or visit www.coilcoatinginstitute.org

5. Myth: You can&#;t handle coil-coated metal without marring the surface.

Fact: Precoated metal can be shipped on flatbed trucks, moved using forklifts, stored as coils for long periods - and still retain a more beautiful and flawless surface than post-painted metal. Prepainted metal can be handled successfully without harming the surface.

Source: NCCA


**************

If you are looking for more details, kindly visit 1 Side 1 Coating Line for coating factory.

SIDEBAR: 10 Signs a Manufacturer Should Consider Prepainted Metal

Converting from in-house post-painted metal to outsourced prepainted metal can save manufacturers money and time, and can ensure that products are the highest possible quality. The most important issues to consider when converting to a prepaint operation are timing, capital outlay, manufacturing costs and environmental compliance. Following are 10 indicators that a manufacturer should consider using prepainted steel or aluminum:

1. In-house paint shop expenses are on the rise. When maintenance budgets are growing and capital investments are required to comply with strict EPA regulations, prepainted metal and aluminum is often a cost-effective alternative to in-house paint lines. Many hidden costs are associated with in-house spray or powder operations. Staffing with trained personnel, equipment, supplies and even environmental compliance all contribute to the expenses of owning an in-house paint shop.

2. Internal operating costs need to be lower. Many manufacturers are searching for ways to lower operating costs in order to remain competitive. Through outsourcing prepainted metals, factories can eliminate costly in-house paint operations and the associated expenses of manning the production line. Some of the major cost savings of prepaint conversion include inventory, environment, insurance, cleaning and waste removal, purchasing raw materials, and operating costs.

3. Plant capacity must be increased. By purchasing prepainted metal, plants are actually outsourcing the painting process and can eliminate or greatly reduce the size of in-house paint shops, generating more floor space for other uses.

4. Coating quality needs improvement. Coil coated metals are uniformly cleaned, pretreated, painted and cured as a flat surface, so that the edge-to-edge and side-to-side variability is virtually eliminated. The prepainted part has two coats of paint (unlike powder coating, which has only one) that are bonded tightly to the metal.

5. Downsizing and/or combining plants is taking place. A good time to consider using coil coated metals is when other major manufacturing changes are taking place. Manufacturers can reduce expenses significantly and increase paint quality greatly by outsourcing the painting process. Coil coated metals can be effectively handled, cut with superior corrosion resistance, joined with welding and adhesives, and formed for many uses&#;all with a beautiful finish.

6. New product models are being considered. Many times when design changes are being made, a prepainted metal can be specified and the new design can be more cost-effective to produce.

7. Manufacturing bottlenecks are reducing productivity. Many delays in a plant are caused by paint issues such as stoppage while parts are painted, dried and cured before moving to the next phase of assembly. These bottlenecks can be eliminated with prepainted metal. Prepainted steel and aluminum are uncoiled, cleaned, primed and painted to a manufacturer&#;s specifications and re-coiled prior to shipping to the factory.

8. It&#;s time to update or replace the paint line. Capital expenditures can be avoided and long-term cost savings achieved by choosing prepainted steel and aluminum, rather than refurbishing or replacing a paint line.

9. A strategy of outsourcing is being implemented. Purchasing prepainted metals is a cost-effective outsourcing option that actually improves the durability of the coating.

10. New fabricating or material handling equipment is being evaluated. When significant changes are made at the plant, it creates an opportunity to improve many aspects of the manufacturing process, including the use of prepainted metal.

Source: NCCA

Links

By Bob Martinelli

Applying aftermarket protective coil coatings is critical to sustaining the full lifecycle of newly-installed HVAC equipment destined for corrosive environments, but many engineers and contractors don&#;t specify this important step.

Coastal areas are the most likely target markets for coil coatings. Salt spray from oceans can prematurely corrode outdoor HVAC coils in as little time as a year if not coated before use. Salt spray can travel as far inland as 10 miles, which creates a huge area of vulnerable equipment on North America&#;s seaboard.

What is new today are coatings that have been packaged in game-changing, convenient easy-to-use aerosol cans.

Protecting HVAC equipment with coil coatings isn&#;t a new concept. For many years, HVAC manufacturers have shipped newly-made coils directly to coating specialists as per the specification of engineers and contractors. Sensitive parts, such as electrical components, are masked-off, then coils are sprayed or electro-coated before the unit is shipped and installed in their corrosive environment destination.

What is new today are coatings that have been packaged in game-changing, convenient easy-to-use aerosol cans. Contractors can now coat coils in their shop or onsite before installation. This skips the past time and effort required to send a coil or the entire unit out for factory-applied coatings. Furthermore, contractors can create an entire do-it-yourself (DIY) coating niche that requires minimal experience or training.

Choose a brand that with a long history and reputation for providing OEM-approved, factory applied coil coatings.

When selecting a coil coating it is important to make sure that the product has passed ASTM B117 test standards for salt spray. It also should have multiple marine and industrial ASTM test standard listings for resisting ultraviolet (UV) rays, acid rain, high concentrations of urban vehicle emission air pollutants and other outdoor contaminants. It&#;s also important to choose a brand that with a long history and reputation for providing OEM-approved, factory applied coil coatings.

When To Use A DIY Coating 

Deciding when to use a coating specialist versus a contractor with field-applied DIY aerosol applications, usually depends on the project scope. For example, it&#;s more economical to request the manufacturer ship 200 new split system condensers to a factory-coating specialist if the units are destined for a beachfront condo complex. However, a contractor using DIY aerosol protective coatings for a beachfront home&#;s condenser(s) can be very economical and reduce the installation time versus shipping the product(s) to and from a coating specialist. As for unit size, typically any HVAC coil in a system 10-tons or smaller is perfect DIY coating application.             

While coastal areas play a large part in coil corrosion, other potential areas where premature coil corrosion can occur are:

• Urban areas, and particularly airports, which have heavy concentrations of airborne vehicle emissions;
• Buildings near or located inside properties of waste water treatment plants;
• Any heavy industrial area that emits airborne chemicals;
• Restaurants where cooking grease particulates are exhausted in  close proximity to the HVAC rooftop system.             
• Heat Transfer and Static Pressure Considerations

Many engineers and contractors have questions about how the coatings will effect a coil&#;s heat transfer performance. While some coating formulas might be borrowed from other industries, only coatings designed specifically for HVAC coils  should be used, because they&#;re formulated for negligible heat transfer loss. These specialty coil coatings are typically only 1.4-ml thick or less, versus other thicker industrial coatings that can negatively affect heat transfer.  

Static pressure is also a consideration, but coatings designed specifically for HVAC coils don&#;t increase the pressure drop through the coil. Instead, they may even lower the pressure drop versus an uncoated coil, because less static pressure-increasing contaminants will reside or adhere to the coil surfaces.

Of course, there&#;s more to consider about corrosion than its effect on static pressure. Corrosion, especially from salt, can create formicary and pitting processes that ultimately lead to leaks.

How DIY Coatings Are Applied

Contractors can apply DIY coil coatings in the field, or in their shop. Obviously, shop-applied coatings are preferred, because of the controlled environment for temperature, humidity with no challenges from wind. 

&#;Clean&#; and &#;dry&#; are key to a good coating adhesion. The first step mandates cleaning the coil with a foaming, non-acid, non-caustic coil cleaner and then thoroughly rinsing the coil. Many contractors believe that new coils are clean. However, most new coils have machining oil residue from the manufacturing process that must be fully removed for successful coating adhesion.

While contractor-applied coatings are designed for new units, if an older unit that has already been exposed to corrosion is being coated, it should be treated first with a purposely-formulated salt and oil removing coil cleaner.

Once the coil has been cleaned and is completely dry, the electrical contacts, moving parts, valves, compressors and other parts not to be coated, are masked off with blue painter&#;s tape, which doesn&#;t leave a residue and is easily removed. It might also be beneficial to coat the unit&#;s compressors and accumulator to minimize the corrosive environment&#;s effect on these key components.

The coating stream is sprayed approximately 4-inches away from the coil in similar movements to spray painting. Some coatings are clear, which allow the coil to appear aesthetically uncoated. Other coatings are blue, for when the applicator prefers to visibly track even coverage of the sprayed area. Drying times for touching is 10 minutes; handling is 20 minutes; recoating is 30 minutes; and a full cure typically requires 48 hours.

During use, the corrosive elements in the air will attack the coil&#;s coating instead of the copper and aluminum surfaces. For this reason, coatings may need a re-application every five to 10 years depending on the environment&#;s corrosiveness.

Coatings are essential for coastal areas, however engineers and conrtactors should also consider the prospect of coating coils in high air pollution areas such as urban centers and airports also. In any corrosive situation, coatings will help improve the efficiency of the unit and maximize the unit&#;s useful life.

                                                      
Bob Martinelli is Director of Corporate Development at RectorSeal® LLC, Houston, Texas (www.rectorseal.com). Modine Coatings recently named RectorSeal the master distributor for GulfCoat&#;, a new coil coating packaged in aerosol cans for contractors to apply at their shop or jobsite. GulfCoat extends the lifecyle of coils and HVAC equipment exposed to coastal area salt, urban air pollution and corrosive chemicals. RectorSeal offers hundreds of skus of HVAC tools and accessories that are sold exclusively through HVAC wholesalers. Martinelli can be reached at [ protected]

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