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Month: June 2022

NEWS ALERT: Formulating with Cortec® Coating Additives? Keep Foam Out of the Equation!

Cortec® offers a variety of VpCI® additives that formulators can use to boost the corrosion protection and salt spray performance of their own coatings. These additives are typically used at a much lower dose than others and are clean and efficient to add. However, the entire benefit of using a VpCI® additive is undermined when too much foam causes defects like pinholes, craters, and curtains. It is therefore imperative to know when a defoamer is needed to avoid these problems.

What Kind of Coating Are You Formulating?

The first sign that you will probably need a defoamer is when you are formulating a water-based coating. While water-based coatings often have important environmental and worker advantages, such as low VOC and easy cleanup, they almost always need a defoamer. This is less common in solvent-based coatings.

What Is the Target Application Method?

Another factor to consider is the expected method of coating application. Spray application is less likely to cause foaming problems, while vacuum coaters are notorious for creating “milk shakes”—paint with more foam than you know what to do with. Flow coaters also have the tendency to create “curtains” where entire strips of metal remain uncoated because an air bubble blocked the paint from flowing underneath that spot.

What Else Will You Be Adding to the Coating?

Coatings can contain dozens of different ingredients—each with a specific purpose—and can vary significantly from one formula to another. This means the defoamer that works for one coating may not work for another. For example, sometimes silicone defoamers may actually cause pinholes or craters due to how they interact with the other ingredients.

How to Choose the Best Defoamer

The best way to avoid foam and ensure that your Cortec® enhanced coating is a success is to talk with your defoamer supplier. Discuss the characteristics and target application of your new VpCI®-powered formula. Then try the recommended defoamers by adding them to the coating and doing a shake test or running them through a blender to see which one is best at reducing foam. It is also a good idea to apply the coating to metal to see how the finish is.

Maximize the Success of Your New Anticorrosion Coating

When you choose a Cortec® additive, the purpose is to make your coating perform better. One of the last things you want to happen is to have the coating fail because of too much foam. Next time you add a Cortec® VpCI® additive to your formulation, be sure to include a defoamer in the discussion to maximize the success of your new anticorrosion coating. Contact Cortec® for more advice on formulating coatings with VpCI® additives here: https://www.cortecadditives.com/contact-us/

Keywords: Cortec Coatings, coating additives, corrosion protection, salt spray performance, low VOC, water-based coating defoamer, silicone defoamers, how to choose the best defoamer, make your coating perform better, anticorrosion coating

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PRESS RELEASE: VpCI®-373 Wash Primer: The Path to Good Coatings Adhesion on Galvanized Steel and Aluminum

Good adhesion is critical to the success of a coatings system, especially when painting metal to protect it from corrosion. Although many of Cortec’s Micro-Corrosion Inhibiting Coatings™ are designed to be applied direct to metal (DTM coatings), a primer is often recommended for improved adhesion. Extra care must be taken for galvanized steel, aluminum, and other metals where adhesion is more difficult. Cortec’s VpCI®-373 serves this purpose as an excellent wash primer for creating a strong bond between metal surfaces and the paint that protects them.

Common Methods for Improving Coating Adhesion
Common methods for improving adhesion on galvanized steel and aluminum include the following:

• Chromate pretreatment/conversion coatings for unpainted aluminum
• Lead and zinc chromate primers for galvanized steel
• Acid etching on galvanized steel
• Applying a wash primer

The first three options have obvious downfalls due to the use of heavy metals and harsh acids that could be harmful for workers. The fourth is an excellent way to keep paint application simple. Wash primers typically are very thin yet promote good adhesion between the metal surface and the chosen topcoat. This can help the protective coating last longer instead of failing prematurely. Without good adhesion, the coating is destined to peel or flake early, giving corrosives free access to the metal surfaces.

VpCI®-373 Wash Primer
VpCI®-373 is a water-based wash primer that creates a good bond on metal surfaces such as galvanized steel or aluminum where adhesion is difficult. VpCI®-373 can be applied at an extremely thin DFT (dry film thickness) of 0.5-1.0 mils (12.5-25 µm) and top-coated with a wide range of water-based or solvent-based Cortec® MicroCorrosion Inhibiting Coatings™ for corrosion protection. It creates a strong bond between the metal and its protective coating to enhance durability and longevity. It can replace chromate treatments and conversion coatings and is an excellent alternative to acid etching in terms of both safety and convenience.

Coating Galvanized Roofing Sheets
VpCI®-373 was used to answer the adhesion question when painting a galvanized roof over a liquid nitrogen loading dock at an industrial site in the Philippines. Lead and zinc chromate based primers had not been enough to avoid adhesion problems, and etching of the galvanized coating with phosphoric acid was expected to lead to coatings failure within a year. This time, the customer chose to clean the new roofing material and apply VpCI®– 373 as a primer, followed by a topcoat of VpCI®-386. VpCI®-373 worked better than standard red lead or zinc chromate primers and was found to fully adhere to galvanized iron roofing sheets.

Good Adhesion or Failed Protection
Corrosion inhibitor coatings lose their value as soon as they begin to peel off the metal they are designed to protect. When special alloys such as galvanized steel or aluminum make adhesion more difficult than normal, VpCI®-373 steps in to provide a proper bond between the metal and the chosen paint, uniting them in a powerful anticorrosion coatings system to make protection more effective. Contact Cortec® to learn more about VpCI®-373 and the means of achieving good coating adhesion: https://www.corteccoatings.com/contact-us-2/

Keywords: wash primer, good coatings adhesion, painting metal, corrosion, corrosion inhibiting coatings, Cortec, direct to metal coatings, corrosion protection, improving coating adhesion, coating galvanized roofing sheets

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CASE HISTORY SPOTLIGHT: Case History #336: Protective Coatings for European Extrusion Plant

The owner of a film extrusion plant in Croatia needed a full protective coatings system that was cost-effective, easy to apply, and took the environment into consideration. Cleaning, adhesion, and overall appearance were other important factors.

All silos, light poles, and the floor were first cleaned with VpCI®– 414 Cleaner/Degreaser (sometimes diluted 15% with water). One coat of VpCI®-386 Green was applied to the silos. VpCI®– 386 Green was also used as a topcoat on the light poles after priming them with VpCI®-373 to improve adhesion to the galvanized surface. MCI®-2026 Concrete Primer and MCI®-2026 Floor Coating were applied to the floor. A Cortec® water-based coating system was also applied to the extrusion line before the manufacturer shipped it from Italy to Croatia.

The Cortec® Coatings allowed the extrusion plant to easily apply a color-coded coatings system that promotes safety and corrosion protection while employing several water-based products.

Keywords: protective coatings, improve adhesion, priming galvanized surface, water-based coating system, Cortec Coatings, floor coating, MCI, priming light poles, corrosion protection

Read the full case history here.

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NEWS ALERT: How to Avoid Pinholes, Craters, and Other Painting Defects for Better Coatings Success!

Pinholes and craters are two common coating defects that make the paint look bad, compromise corrosion protection, and require a complete redo of the project. By understanding the root cause of these issues, painters can avoid them in the first place and promote the best possible performance of their Cortec® Coatings system.

Where Do Pinholes, Craters, and Similar Defects Come From?

Pinholes are tiny holes in the coating. Craters are larger holes. Both create weak points where corrosion can begin. These defects are almost always caused by contamination. Grease, dirt, oil, or dust on the metal changes the coating’s surface tension, causing the rest of the paint to pull away from that spot and create a gap in the coating. Pinholes can also be caused by air bubbles that do not break until after the coating has dried. One culprit is vigorous mixing that creates too much foam.

How to Prevent Pinholes and Craters

The number one way to prevent pinholes, craters, and similar defects is to clean and dry the surface before coating it. Rinsing the metal with a VpCI®-41x Series cleaner is especially beneficial for surfaces that have been sandblasted down to white metal and are at risk for flash rust as they wait to be painted. Foam control is also important. If painters are mixing the paint too rapidly, they simply need to slow down to create less foam. Other times, the problem takes place in production, and the coating manufacturer may need to modify their formula.

Do It Right the First Time

No one wants to redo a paint job and have their previous efforts wasted. That is why it is critical to guard against contamination and excess foam from the outset. By taking the precautions mentioned above, painters can get their Cortec® Coatings application off to a good start for better coatings success in the long run. Contact Cortec® Coatings for further assistance to prevent and diagnose these and other coatings problems:
https://www.corteccoatings.com/contact-us-2/

Keywords: how to avoid coating defects, how to avoid pinholes, painting defects, Cortec Coatings, flash rust, foam control, paint defoamer, corrosion protection, painting surface prep, coatings success

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How to Avoid Mud Cracking When Applying Anticorrosion Coatings

No one wants to apply a paint or anticorrosion coating only to come back later and find that it has dried to look like cracked mud. Not only does the texture look bad, but it also leaves behind cracks that go down to the metal surface, making it more susceptible to corrosion. While the problem of mud cracking can only be resolved by removing and reapplying the coating, it is very easy to prevent by following the guidelines below!

Why Does Mud Cracking Happen?

No matter how good a coating is, mud cracking can occur when the coating is applied too thickly. This is because solvents and water evaporate out of the paint at a certain rate as the coating dries. If the coating is too thick, the surface of the coating dries more quickly than the volatiles underneath can evaporate. Once the surface dries, the volatiles are trapped below, and the only way they can escape is by cracking the dry surface layer to get out. While mud cracking can happen with either solvent-based or water-based coatings, it is more common in water-based coatings because water evaporates more slowly.

How Can You Prevent Mud Cracking?

The solution for preventing mud cracking is extremely simple: follow the manufacturer’s recommendations for coating thickness. The coating manufacturer already knows how the coating will behave and usually provides both a wet film thickness (WFT) and a dry film thickness (DFT) recommendation on the product data sheet. To avoid mud cracking, the coating applicator simply needs to apply the recommended WFT, measuring coating thickness with a WFT gauge to make sure it is correct.

If only the DFT is listed, the painter can figure out the proper WFT based on the recommended DFT and the percent volume of solids. This percentage tells how much of the coating will remain after the volatiles have evaporated. For example, an approximately 50% volume solids coating such as VpCI®-395 will lose about half of its WFT by the time it dries. To get 3 mils (75 µm) DFT, the coating will need to be applied at 6 mils (150 µm) WFT. A coating such as EcoShield® VpCI®-386 with a 31% volume of solids will lose a little more than two-thirds of WFT by the time it dries, meaning 9.6 mils (240 µm) WFT are needed to achieve 3 mils (75 µm) DFT.

What If You Need a Thicker Coating?

Sometimes, it is necessary to apply a thicker coating than normal. If this is the case, the painter can avoid mud cracking by applying the paint in multiple coats and allowing them to dry in between each application.

Remember to Follow Instructions!

Often the best way to achieve success is right in front of us. By following WFT recommendations on a coating’s technical data sheet, painters can avoid unnecessary problems and rework caused by mud cracking. Contact Cortec® for more coating application tips and advice on selecting an anticorrosion coating for your specific application: https://www.corteccoatings.com/contact-us-2/

Keywords: Cortec, Cortec coatings, anticorrosion coatings, mud cracking, how to avoid mud cracking, measuring coating thickness, water-based coatings, solvent-based coatings, coating application tips, measuring WFT

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PRESS RELEASE: Paint On, Peel Off: Are You Ready to Try VpCI®-372 Peelable Coating for Corrosion Protection?

When choosing a coating, painters typically want one with good adhesion that will not peel quickly. But in some cases, a peelable, strippable coating is exactly what users need for a temporary coating application. Factor in corrosion protection, and manufacturers and maintenance crews have VpCI®-372, a flexible option for removable metal coatings applications.

How VpCI®-372 Works

VpCI®-372 from Cortec® Corporation is a fast-drying, water-based, low VOC acrylic peelable coating that provides corrosion protection in sheltered applications. It can be applied to metal surfaces by spray, brush, or dip. It dries quickly to a clear coat or can be tinted to match some existing color schemes or to provide easy identification of parts. When protection is no longer needed, the user can peel the coating off by hand and discard it as solid waste. This is an exceptional advantage, allowing workers to keep the metal clean, dry, and protected without having to expose themselves to solvents and paint removers.

When to Use VpCI®-372

VpCI®-372 should be used when packaging and other rust preventative coatings are not optimal. The following questions can be helpful in guiding the decision:

  • Does the shape of the metal make packaging difficult?
  • Would packaging removal at the end of preservation interrupt the workflow?
  • Do I need temporary protection rather than a permanent topcoat?
  • Do I want to be able to remove the coating without solvents or cleaners?
  • Will my component be exposed to light physical abrasion (e.g., gravel bouncing off the road)?
  • Do I have metal parts that need to be masked off?

If the answer to any of these questions is “yes,” the application is a good candidate for VpCI®-372 corrosion protection.

Where to Use VpCI®-372

VpCI®-372 peelable coating can be used on equipment in transit, in storage, and sometimes even in operation. For example, instead of applying a greasy rust preventative to new parts being shipped to the assembly plant, a manufacturer can spray the bare metal components with VpCI®-372, which can be peeled off clean and dry when the end user is ready to assemble the parts. Other applications include:

  • Threads, Splines, and Dynamic Profiles – VpCI®-372E is an extra thick version of Cortec’s coating that can be painted on to protect threads, splines, machined areas, or other metal surfaces with dynamic profiles.
  • Winter Equipment Storage –Maintenance crews putting away metal boats or other equipment for the winter can spray metal surfaces with VpCI®-372 and simply peel it off in the spring.
  • Component Masking – Coating applicators in a paint booth can mask off specific areas of a part with VpCI®-372 before spraying the rest of the component with a permanent coat. The VpCI®-372 collects the overspray and can be peeled off to reveal a clean, bare metal surface after the paint application.
  • Heavy Equipment Storage – VpCI®-372 can even be sprayed on dump truck beds, forklift tines, or grader blades of heavy equipment that has to sit in storage for extended timeframes. The equipment will be protected but ready to drive off at a moment’s notice, with or without removing the coating.

Give Peelable Coatings a Try

Peelable coatings work better in some applications than in others. The key is to determine what factors are at play for a particular preservation need. If your application calls for temporary corrosion protection and is not suited to packaging, it may be time to put peelable, strippable coating to work by ordering a sample of VpCI®-372 or VpCI®-372E. Contact Cortec® for advice today: https://www.corteccoatings.com/contact-us-2/

Keywords: corrosion protection, peelable coating, strippable coating, low VOC coating, transit coating, heavy equipment storage, winter equipment storage, Cortec, Cortec coating, metal coatings

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