Category: NEWS ALERTS

Do you ever have questions about good surface prep and coating adhesion when working with direct-to-metal coatings? Cortec’s Technical Service Manager, Rick Shannon, recently shed light on some frequently asked questions (FAQs) that come up when talking with Cortec® Coatings users.

1. Do I Need to Remove Cortec® VpCI®-41x Series Cleaners Before Coating?

If a sandblasted metal surface is going to sit exposed at least 24 hours before painting, it should be cleaned with a VpCI®-41x Series cleaner to remove grit and grime and inhibit flash rust. Since cleaners such as VpCI®– 414 and VpCI®-416 contain flash rust inhibitors that temporarily adsorb on the metal surface, the question arises of whether the cleaner itself needs to be rinsed off, as well, to ensure good coating adhesion.

The answer depends on how the cleaner was applied and how it has dried. Typically, Rick would recommend rinsing off the VpCI®-41x Series cleaner before painting, especially in areas where the wash water has pooled. However, if the VpCI® cleaner was applied by power-washing and has dried completely without pooling, adhesion should not be an issue, and the VpCI®-41x Series may not need to be rinsed off at all.

2. How Soon Can I Apply a Second Coating of CorrVerter®?

Another common question concerns recoat time. This is important because not waiting long enough for each coat of paint to dry before applying the next one can have a serious impact on adhesion.

In the case of CorrVerter® Rust Converting Primer, Cortec® recommends applying a second coat only after the first is dry to touch. Practically speaking, this often balances out to at least six to eight hours depending on the location and time of year. For instance, in the middle of July in the Northern Hemisphere, CorrVerter® may be ready to recoat in just three hours because the heat dries it out so quickly. But in late autumn as the temperatures fall, it may be necessary to wait overnight to get a full cure.

For any water-based coating, cooler temperatures greatly extend the recommended recoat time because water evaporation rates slow down. In fact, a cool, humid day could double recoat time. If painters have any question of whether a coating is ready to recoat, Rick recommends waiting overnight before applying the second coat. If for some reason it is not possible to wait, he suggests doing a coating adhesion test or solvent rub to see if the coating has cured.

3. How Long Can I Wait to Recoat?

On the other end of the spectrum is the issue of how long is too long to wait before recoating. Rick shared that for some Cortec® Coatings, recoating can wait indefinitely. Coatings such as EcoShield® VpCI®-386 or CorrVerter® can be recoated even a year later as long as the surface is clean. Other Cortec® Coatings, such as VpCI®-395 and VpCI®-396, cannot wait too long before recoating because their resins get much harder. If more than 72 hours have passed since applying these two coatings, the painter will need to scuff the surface before recoating to improve adhesion.

How to Make Use of FAQs

Many variables enter into the equation for each FAQ, and the answers are not always exactly the same. However, they provide a general rule of thumb on how to work with surface prep and coating dry time. The best way to make use of these FAQs is to use a healthy dose of common sense to apply the advice to each unique case. If uncertainty about a particular application still lingers, you can always contact Cortec® Technical Services for further help. Perhaps your own inquiry will even make it on a future list of FAQs!
https://www.corteccoatings.com/contact-us-2/

Keywords: Coating FAQs, Cortec Coatings, coating adhesion, good surface prep, rust converting primer, how soon can I apply a second coating, how long can I wait to recoat, coating adhesion test, solvent rub test, Cortec

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Have you ever been applying a coating out in the field and wanted to know if enough time had passed to apply the topcoat? Our newest demo video shows how to do a quick solvent rub test to make sure your coating has cured.

In this short video, Cortec® Technical Services Manager Rick Shannon explains how to do a solvent rub test and then demonstrates the technique on a panel coated with VpCI®-395 Water-Based Epoxy Primer. Wearing gloves, he rubs a towel dipped in solvent (MEK) back and forth across the panel 25 times to see if any of the coating will come off or fade. Rick finishes the solvent rub with no damage to the coating, confirming that it has fully cured and is ready to be top-coated with another Cortec® Coating.

Making sure a coating has fully cured before applying the second coat on top is critical to good adhesion and the success of the entire coatings system. Without good adhesion, the coating will chip or peel off more easily, exposing the metal to corrosive elements that could damage the surface and cause coating failure altogether, negating corrosion protection. When time is limited and cold weather or other situations make it unclear how long you should wait before recoating, a solvent rub is a quick and easy way to check coating cure. Watch this demo to be prepared next time you need to do an impromptu MEK solvent rub test out in the field: https://www.youtube.com/watch?v=NrdAQiS77uk

Keywords: coating failure, Cortec demo video, how to check coating cure, coating adhesion, good adhesion, how long should you wait before recoating, Cortec, Cortec Coatings, MEK solvent rub test, corrosion protection

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We are pleased to release a new demo video on how to test coating adhesion! This test can be very important for coating applicators who want to make sure their first coat of paint has cured enough to apply the second coat-or for applicators who simply want to paint over an old coating. Good coating adhesion is critical to the success of an anticorrosion coating system because if the coating does not stick to the surface, protection is lost. If adhesion is good, the coating can do its job!

Now, painters can watch our new demo video to see how Technical Services Manager, Rick Shannon, tests coating adhesion according to ASTM D3359 on a panel coated with one of Cortec’s Micro-Corrosion Inhibiting Coatings™. Using a special tool from his adhesion test kit, he makes perpendicular cuts to get 100 tiny squares on the surface of a coating. After brushing off the residue, he uses a piece of masking tape to see how many squares of paint he can pull off. Based on this, he calculates the percentage of failure and the level of adhesion.

At the end of the video, Rick explains how to do the same basic test in the field without special equipment. The only tools needed are a utility knife and masking tape. Rick demonstrates how to make 11 cuts in each direction (to get 100 squares), brush off the paint residue, and see how many squares of paint can be pulled off with the masking tape.

Rick often recommends testing coating adhesion to customers. Now, instead of having to get the directions over the phone or via email, customers can watch this short demo video to see how it is done! Watch now: https://www.youtube.com/watch?v=XXVqiZeo4mI

Keywords: Cortec demo, how to test coating adhesion, adhesion test kit, Cortec Technical Services, anticorrosion coating, micro-corrosion inhibiting coating, demo video, adhesion test demo video, good coating adhesion, testing coating adhesion

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The fertilizer industry would be one of the finalists if awards were given to the most corrosive industries. Although fertilizer makes a huge difference for agricultural productivity, it has a negative effect when it comes to vehicles and structures, sometimes eating through eight inches (20 cm) of concrete in just five years and deteriorating fertilizer spreader trucks in a few short months. Cortec® is looking at ways to help the fertilizer industry pull out of this vicious cycle of equipment degradation through the strategic use of Cortec® Coatings.

Fighting an Uphill Battle Against Corrosion

Without special protection, trucks that spread fertilizer are destined to rust. Fertilizer blends made of ammonia nitrate, nitrogen, phosphate, and potash enrich the soil but take their toll on the trucks that spread them on fields for just a few summer months. In fact, fertilizers tend to be more corrosive than deicing salts used in harsh winter environments. Fertilizer corrodes practically any metal it touches: dump truck beds, brace bars, spreader pans, lines and pumps under the truck, and air intake filters. The economic cost is that fertilizer trucks often have to be ripped down to the frame and rebuilt every two years—a high price tag for these expensive assets.

Implementing a Preventative Maintenance Plan

In the past, fertilizer truck owners have taken it as a matter of course that their equipment will rust and need to be rebuilt or replaced every few years. However, for some, a new realization is dawning that it does not have to be this way. Cortec® Coatings offer an excellent preventative maintenance plan that can extend the service life of fertilizer equipment. A small annual investment can have a potentially huge savings that could have benefits for years to come.

VpCI®-391 is a water-based removable coating that dries to a clear non-tacky film. It is great for spraying over painted surfaces without significantly changing the appearance of the equipment. It has a low VOC of 0.4 lbs/gal (48 g/L) and is easy to work with. Although it is considered a removable coating that can be washed off relatively easily with an alkaline cleaner, users often leave it on for ongoing corrosion protection because it is so inconspicuous. VpCI®-391 can be sprayed over both painted and unpainted metal surfaces on fertilizer trucks. For the underbody, a tough coating of VpCI®-398 Undercoat is recommended. VpCI®-398 dries to a soft, non-brittle black film that helps protect against cracking and coating damage from the impact of gravel or debris.

Revolutionary Solution for Front-End Loaders

Over 10 years ago, a barge loading company discovered the benefits of VpCI®-391 when it started applying this removable coating for annual preventative maintenance on front-end loaders used to move large volumes of deicing salts and/or fertilizers at ports. The harsh exposure typically made the loaders look 10 years old in just one year, requiring replacement every two or three years. The equipment started lasting much longer when the company started applying VpCI®-391 over the top, bottom, front, and back—all accessible metal—of the loaders. The company loved the coating and has continued to apply it as part of annual preventative maintenance for many years.

Fight Corrosion, Cut Costs

Fertilizer is a formidable but not impossible corrosion challenge to tackle. With simple preventative fleet maintenance using Cortec® Coatings, fertilizer companies can help their trucks and equipment last longer, saving huge costs with just a small annual investment. Contact Cortec® to learn more about developing a solution for your fertilizer equipment: https://www.cortecvci.com/contact-us/

Keywords: fight corrosion on fertilizer trucks, Cortec Coatings, fertilizer corrosion, preventative maintenance, extend service life, underbody coating, low VOC coating, fleet maintenance, Cortec, most corrosive industries

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June 21, 2022

When cleaning or degreasing metals, it is important to choose a cleaning fluid that guards against flash rust. It is also important to consider the method of cleaning, since high pressure and high agitation can create a foaming mess. To address both concerns, Cortec^® Corporation offers VpCI^®-418 LM, a non-foaming alkaline cleaner with flash rust protection.

Preventing Flash Rust on Freshly Cleaned Metal

Metals are especially susceptible to flash corrosion after cleaning, which is why Cortec^® has developed VpCI^®-41x series cleaners/degreasers that contain flash rust inhibitors. These corrosion inhibitors are ideal for protecting metals that cannot be immediately coated. Other common uses include dual cleaning/corrosion protection of the following:

• Machinery, engine blocks, or forgings coated with grease or oil deposits
• Plate, sheet metal, and metal castings covered with oily films prior to painting or pickling
• Metal parts contaminated with stamping, drawing, or buffing compounds
• Metal structures

Overcoming Foam Problems in Parts Washers

When cleaning the items mentioned above, foam is usually associated with a better cleaning experience. That changes with parts washers, where high agitation creates excess foam that could overflow out of the machine and onto the floor. Pressure washing and power washing can have similar problems. VpCI^®-418 LM is good for both applications because it is non-foaming and performs best with mechanical action. VpCI^®-418 LM can be used on a variety of metals (carbon steel, stainless steel, cast iron, galvanized steel, brass [30% Zn], copper) and may be used at different dosages for light, medium, or heavy-duty cleaning.

Next time you need to clean metal parts or structures in a high agitation environment, remember to take advantage of the flash rust corrosion protection and non-foaming aspects of VpCI^®-418 LM. Contact Cortec^® to learn more about our portfolio of flash rust inhibiting cleaners/degreasers: https://www.cortecvci.com/contact-us/

Keywords: metal cleaning, flash corrosion protection, corrosion protection, cleaning and degreasing metals, flash rust protection, rust inhibiting cleaners, foam problems in parts washers, preventing flash rust, Cortec, VpCI

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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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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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