Category Archive: Industry News

Pretreatment for Painting

A high-quality conversion coating is essential for the durability of painted metal goods. The process of applying an inorganic conversion coating to a metallic surface involves removing any surface contaminants, then chemically converting the clean surface into a non-conductive, inorganic conversion coating. Conversion coatings increase the overall surface area and promote adhesion of the subsequently applied organic film. In addition, conversion coatings change the chemical nature of the surface, which increases corrosion resistance. It is these two functions, increasing surface area and changing the surface chemistry, that serve as a base for preparing the substrate material for paint finishes.

There are a number of driving forces in the pretreatment industry today with quality, cost and the environment being the most predominant. While these aren’t new issues, the pretreatment industry has responded to the needs of finishers by creating technology to address each of these requirements. In understanding the complete manufacturing process, including paint formulations, application equipment and regulatory impacts, it’s possible to address each driver simultaneously.

The conversion coating chemistries predominately used today are either zinc or iron phosphate. There is movement to replace these technologies with new types of phosphate-free or very-low-phosphate metal pretreatments. The new-generation technologies have been commercialized by many vendors over the past several years and are rapidly becoming industry standards. Regardless of the chemistry, conversion coatings are used to promote adhesion and improve corrosion resistance. Depending on the conversion coating and the desired performance, the conversion coating can be applied at a number of points in the process.

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Providing Superior, Extended Corrosion Protection

The hybridized matrix membrane developed in the study presents a unique design strategy for highly hydrophobic coatings showing great long-term corrosion resistance.

Addressing the Corrosion Problem of Magnesium Alloy
Thanks to their low weight, high specific strength, and recyclability, magnesium (Mg) alloys are employed across many industries, including the automotive and aeronautical sectors and electronic equipment.

Despite this, magnesium alloys can easily suffer from corrosion in aqueous conditions because of their strong chemical activity, restricting their widespread applicability.

Multifarious techniques, including electrodeposition, ionic implants, and surface coatings, have been used to improve the corrosion resistance of magnesium alloys.

Surface coatings, particularly organic surface coatings, offer great corrosion resistance with the advantages of being facile and inexpensive.

PDMS Coatings for Better Corrosion Resistance
Compared to traditional organic coatings, PDMS is a unique polymeric material having low surface energy, high chain flexibility, superior thermal oxidation resistance, and chemical corrosion resistance thanks to the robust silicon-oxygen-silicon backbones.

PDMS is extensively used in flexible electronic devices and microfluidics. Moreover, due to its strong water-repellent nature, PDMS is a preferred material for corrosion resistant coatings.

While PDMS polymer coatings exhibit strong corrosion resistance and barrier function, their protective powers become weaker when they absorb water after extended contact with a corrosive medium.

Meanwhile, doping or hybridization can lead to the formation of microcracks and microspores in organic coatings, which ultimately causes poor corrosion resistance durability.

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The Powder Coating Process

Powder coating is a dry finishing process used to apply a dry coating material. The coating material is made up of finely ground particles of resin and pigment for color, along with other additives for specific functions such as gloss or hardness. The dry powder coating is delivered to a spray gun tip that is fitted with an electrode to provide an electrostatic charge to the powder as it passes through a charged area at the gun tip. The charged powder particles are attracted to a grounded part and are held there by electrostatic attraction until melted and fused into a uniform coating in a curing oven.

Since its introduction more than 40 years ago, powder coating has grown in popularity and is now used by many manufacturers of common household and industrial products. In North America, it is estimated that more than 5,000 finishers apply powder to produce high-quality, durable finishes on a wide variety of products. Powder-coated finishes resist scratches, corrosion, abrasion, chemicals and detergents, and the process can cut costs, improve efficiency and facilitate compliance with environmental regulations.

Because powder coating materials contain no solvents, the process emits negligible, if any, volatile organic compounds (VOCs) into the atmosphere. It requires no venting, filtering or solvent recovery systems in the application area such as those needed for liquid finishing operations. Exhaust air from the powder booth can be safely returned to the coating room, and less oven air is exhausted to the outside, making powder coating a safe, clean finishing alternative and saving considerable energy and cost.

Theoretically, 100 percent of the powder overspray can be recovered and reused. Even with some loss in the collection filtering systems and on part hangers, powder utilization can be very high. Oversprayed powder can be reclaimed by a recovery unit and returned to a feed hopper for recirculation through the system. The waste that results can typically be disposed of easily and economically.

Powder coating requires no air-drying or flash-off time. Parts can be racked closer together than with some liquid coating systems, and more parts can be coated automatically. It is very difficult to make powder coating run, drip or sag, resulting in significantly lower reject rates for appearance issues.

Powder coating operations require minimal operator training and supervision when compared with some other coating technologies. Employees typically prefer to work with dry powder rather than liquid paints, and housekeeping problems and clothing contamination are kept to a minimum. Also, compliance with federal and state regulations is easier, saving both time and money. In short, powder coating can provide the five “Es:” economy, efficiency, energy savings, environmental compliance and an excellent finish.

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What is CARC Paint?

CARC (Chemical Agent Resistant Coating) is a paint used on military vehicles to make metal surfaces highly resistant to corrosion and penetration of chemical agents. It provides surfaces that are easily and effectively decontaminated after exposure to liquid chemical agents.

There are three types of coatings in the CARC system: anepoxy polyamide primer, an aliphatic polyurethane paint (PUP), and epoxy polyamide enamel. Each of the coatings is supplied as a two-component system. When the two components are combined, a terminal reaction begins which makes an impermeable coating.

During application of CARC, the surfaces to be coated with CARC must sometimes be stripped. After stripping, the surface must be cleaned of all oils, grease, and water. When the item is ready for coating, the two components are mixed and allowed to stand for a prescribed period. The mixture must then be applied within a given time period known as its “pot life” in order to be effective.

Trans-Acc is fully certified to meet the military’s most strict CARC paint requirements and is an experienced CARC supplier to the defense industry, for use in various military applications. For more information about outsourcing CARC Coating solutions, see Military CARC Coating Services.

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Noting advances in powder coating

Complete coverage of powder coating is always a worthwhile goal, both in terms of application and knowledge about the subject.

More metal fabricators are finding themselves in a position where they are expected to take on responsibility for finishing metal parts. Either OEM customers want them to take on powder coating activities, or at the very least they want the shops to coordinate the finishing process in addition to the fabrication.

Of course, in this economy, many metal fabricators aren’t in a position to say no to such requests. Fortunately, powder coating technology has advanced to the point where it’s more user- and production-friendly than ever.

It’s one of the younger metal finishing technologies on the marketplace, having appeared on the manufacturing scene in a large way in the 1970s. The technology grew rapidly in the 1980s as key industry segments, such as appliance and architectural, gravitated to it, and powder coating usage grew with international expansion in the 1990s. The growth of the technology is not as robust as in past decades, but this lull has put pressure on the material and application equipment sector to develop new products in an aggressive manner.

The basic premise for powder application remains the same. Dirt, oils, and lubricants have to be removed from the material with chemicals, which also help prepare the metal surface for powder application and improve powder adhesion. These pretreatment chemicals usually are applied in a spray process, but sometimes a submersion method with several tank stages is used. Once the parts are dried (see Figure 1), they enter a booth where an application gun shoots electrostatically charged particles at the grounded metal parts (see Figure 2). The powder adheres to the parts as long as electrostatic charge remains on the powder, which is usually more than enough time for the parts to travel to a curing oven. The oven provides the elevated temperature necessary to melt the powder and cause the material to flow out, creating a skin over the metal part.

The powder coating industry is not one marked by regular technological revolution, but that doesn’t mean noteworthy advancements haven’t taken place over the last five to 10 years. Here are five developments you should be aware of if your company is increasing its involvement in powder coating.

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How To Better Control Powder Coating Film Thickness

Q: We struggle to avoid light coating in some areas of our parts. Our application is all manual so we have focused on working with operators to help them understand the critical areas and work harder at getting enough powder in the inside corners and tight spaces, but they still have some failures. We also have some heavy coating at times and that may be related to the effort to avoid the coating. Any suggestions on how to better control film build?

A: This is an age-old question that has been considered a few times in this and other columns. There are many factors that impact film build control so the answer is not simple. Start by considering the key word in the sentence — “control.” Control implies a systemic approach to a problem by implementing clear and repeated methods and techniques. The things that need to be controlled include powder fluidization, flow rate, gun-to-target distance, stroke pattern and speed, parts racking, line speed and presence of good contact to the ground.

It starts with racking. Do you have the right number of parts per minute traveling through the booth? If you have too many, the coating will vary toward the light side. If you give the parts too much space, the coating can be heavy in some areas. Spacing needs to be adequate for good access without leaving too much empty air in the pattern. Parts should be close enough for good efficiency without limiting access to all areas of the part. The position needs to assist vision and ergonomic access to the part surface. Parts need to be held steady and consistently. Hooks need to be clean and in good repair. The line speed and amount of part surface needs to be comfortable for the operators so they can cover all surfaces without racing to keep up with the line.

Next, make sure that the powder is flowing smoothly and consistently from the gun tip in adequate volume for the amount of part surface that is traveling through the booth. Control the velocity and pattern to allow a high percentage of efficiency and minimize overspray.

Work on consistent patterns so the parts get the same coverage all the time. Use some research and trials, if necessary, to make sure you have the best possible setup and spray pattern. Measure the film thickness and help the operators see what is happening to each area of the part.

Finally, work on standard methods for all of these operational variables so you can improve on consistency. Standard operating procedures and well-conceived racking arrangements can provide the improvement you are looking for in film-build control.

Read more: How To Better Control Powder Coating Film Thickness

New Paint Helps Protect Warfighters

You’ve probably seen plenty of Army vehicles on the road. They might be standard olive drab, or possibly a desert camouflage pattern. However they’re painted, the basic material for the coating is called CARC, Chemical Agent Resistant Coating.

“Our Nato customers, our allies, they are all using this. This paint is in theater,” said Pam Clark from Huntsville’s CFI Military Solutions. She is not talking about CARC.

Pam is talking about “Intermat Stealth, Anti-Thermal Spraying Coating”. It’s a paint CFI was showing off in its booth at the recent Space and Missile Defense Symposium.

“We have a paint that covers their IR signature,” said Pam. IR stands for infra-red. You can think of it as the heat signature. Obviously, if a vehicle has a less detectable heat signature it would be less visible to a sensor that homes in on heat. The kind of sensors that might be on an enemy drone, or a heat-seeking missile.

“We’re defending the people who are inside the buildings or inside the Humvee. We’re defending their lives. If they can’t be seen, and they can’t be sought out by missiles, they can’t be hurt,” said Pam.

There’s a photo from CFI that shows three vehicles. One is mostly painted with Intermat, and it’s far less visible than a similar vehicle painted with CARC. A third vehicle is entirely painted with Intermat and its heat signature is significantly harder to detect than the other two vehicles. CFI is in the process of doing testing, and that’s where another benefit of their paint became obvious.

“We have data that backs it up now on the Stryker (vehicle) that we had down here. It will keep the inside cooler too,” said Pam Gardner.

She believes the testing will prove the worth of the paint for the U.S. Military, and as Pam has already said, it’s being used by NATO allies. Something that lessens the heat signature would save lives. If it keeps a vehicle cooler it would protect sensitive instruments, which could also be a lifesaver.

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Military “STARs” Are Born With Paint Facilities

The Yermo Annex Marine Corps. Logistics Base in California and the Corpus Christi Army Depot Aviation Center in Texas have acquired new systems to help train and enhance employees’ painting abilities.

The bases obtained a Spray Technique Analysis and Research for Defense (STAR4D) training program from the University of Northern Iowa, a virtual training that the military says improves quality while reducing time, materials and toxic exposures.

The military branches are using the systems in training to apply chemical agent resistant coatings (CARC) required on all combat, combat support and combat service support equipment. CARC is a polyurethane paint that provides superior durability, extends service life for military vehicles and equipment, provides surfaces with superior resistance to chemical warfare agent penetration, and greatly simplifies the process of decontaminating equipment when necessary.

Mike Jackson, supervisor at the Yermo Annex Marine Corps Logistics Base, says the STAR4D improved transfer efficiency.

“It is hands-on training allowing workers to judge their distance and thickness of spray, and allow them to develop speed without the waste of using a booth,” Jackson says. “It prepares workers, giving them an idea of what is to be expected and develop a rhythm.”

The military says that currently the maintenance centers in Barstow, Calif., and Albany, Ga., are experiencing a 40 percent transfer improvement efficiency with a 20 percent projected cost saving. That equates to an average savings of 60 gal of paint per year for every 300 gal used, or about $200,000 in savings.

“We have the ability to train our employees without having to worry about the amount of paint we are using, or any air pollution that we would have to worry about from constantly using the painting booth,” Jackson says. “The system is constantly getting better, and the more it does, the better we can train our employees and also save money on things such as paint. Along with saving the time that we would be using the booth for training, we can now use it for pushing more products off the line.”

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The Sandblasting Media Market to record USD 14.8 billion revenue by 2027, Says Global Market Insights Inc.

Sandblasting machines find usage in tasks like rust removal, paint removal, and domestic civil repair works. Increasing demand for sandblasting machines is primed to enhance sandblasting media consumption. Mounting adoption of sandblasting media in the metalworking, construction, and automotive sectors is calculated to drive market growth over the forecast timeline.

Aluminum oxide is commonly used as a blasting media on glass, wood, and metal, among other materials owing to its aggressive nature. Driven by prevalent adoption of aluminum-oxide media in the construction industry, the aluminum oxide product segment is projected to register solid growth through the study timeframe.

Key reasons for sandblasting media market growth:

Surging demand in metalworking sector.
Increasing adoption in construction industry.
Prominent usage in automotive applications.
2027 forecasts show ‘automotive’ segment retaining its dominance:

With respect to end-user, the automotive industry segment is anticipated to exhibit stable development at approximately 7% CAGR over the estimated timespan. Sandblasting can easily remove rust, powder coating, paint, body filler, and chrome. Thus, it is utilized in automotive restoration for removing rust and repainting to obtain high-quality finish on vehicles, such as cars, among other applications. Soaring uptake of automotive sandblasting is expected to bolster the segmental growth through the forecast period.

Read more: The Sandblasting Media Market to record USD 14.8 billion revenue by 2027, Says Global Market Insights Inc.

Powder Technology’s CARC Powder Topcoat Approved by ARL

The U.S. Army Research Lab in Aberdeen, Maryland, has approved Powder Technology’s MIL-PRF-32348 Type III, Class I, Tan 33446 powder topcoat.

The new product listing is now shown online on the ARL’s ‘Qualified Products Database,’ and the manufacturer’s designation is product number PT-QS01-TS0001. This latest product marks Powder Technology’s ninth ARL-approved powder coating.

“When used in conjunction with one of our many approved primers, the ultralow gloss Tan 33446 topcoat offers a complete protection solution for military assets,” says Quint Towle, Powder Technology’s director of sales and marketing.

Powder Technology is ISO certified and ITAR registered. Visit powdertechnology.com.

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