For any coating application, it is extremely important to know your coating, to ensure you get the application done right, and to ensure best results. But let’s face it, if you aren’t the coating manufacturer, knowing the coating and application parameters can be a daunting task. That’s why manufacturers supply Cliffs Notes versions of the important stuff in the form of Technical Data Sheets. Technical Data Sheets give most of the information you need to help avoid common pitfalls in the coating application. Following these recommendations help to ensure the best possible outcome on the job site. While complete information, and assistance is typically offered direct from the manufacturer, the technical data sheet should be used as a fail-safe resource for pinpointing application parameters for any project. There are lots of tips to share to increase application success rates, but two of the most important components to getting things right, are to 1) comply to surface preparation requirements and 2) stay within the recommended film thickness.
Rule #1: Comply with Surface Preparation Requirements
You may have seen the statement “all surfaces must be clean, dry, and contaminate free” in the surface preparation section of our data sheets. That is the starting place of any paint application. At the very least, a solvent wipe is recommended for removing any oils, grease, or other contaminates on the surface. Solvent wiping should take place before any further surface preparation is started. Blast cleaning may also be recommended. If so, it generally means the coating requires a surface profile to achieve intended adhesion properties or to enhance adhesion for specific services.
Have you asked, “Why did the paint fall off my equipment?”
Watch out for adhesion issues! You can experience adhesion issues for a number of reasons, but the top culprits are dirty substrates or little to no surface profile.
Keep it Clean.
Tape tests can be used prior to painting to ensure a clean substrate. Simply apply clear tape to the part you are painting…..if dust, rust, or other debris is apparent on the tape when removed, you can easily determine how your adhesion could be affected. If 50% of that tape has debris, you are decreasing your adhesion by approximately 50%!
Pinholing is another issue that can arise from unclean surfaces. Pinholes are small voids in the film that can be caused by moisture, improper atomization, but most often from unclean surfaces!
Know Your Profile!
Not the one on LinkedIn or Facebook, but the one you create by hand tool or blast cleaning your substrate. Surface profile should be measured prior to application to ensure proper a profile has been achieved. If your profile is non- existent or too low, the coating will have less surface area and/or “tooth” to bite down upon. On the opposite end of the spectrum, you can also have too much profile which can result in improper coating coverage of surface peaks ultimately resulting in premature surface rusting.
If you experience adhesion problems, cross hatch or pull-off adhesion testing can be administered to determine the exact cause of adhesion failure.
Rule #2: Stay Within Recommended Film Thickness
When it comes to coating thickness, you must fight the urge telling you that if some is good, more is better. Know your target range and give a nod to Goldilocks….she knew best. The trick is not too little, and not too much! Check that Technical Data Sheet to find out what range is Just Right!
Is My Paint Too Thin?
Applying your coating too thin can result in uncovered peaks in the surface profile. You might not be able to see this with your naked eye, but you will see premature rusting in areas that have too low of a film build. You can also compromise the service life of your coating or coating system when you apply too little. Measuring wet film thickness (WFT) or dry film thickness (DFT) can keep you in check!
Is My Paint Too Thick?
Applying a heavier coat of paint than recommended can lead to an array of problems. These problems include runs, mud cracking, solvent entrapment, improper film development or failure.
If you experience runs in your paint during application, you are most likely applying too much paint or with too much pressure. In any case, the result is excessive film build in the run areas. Mud cracking occurs when the film build is too great and the outer surface dries faster than the underlying coating. The outer layer will contract first, or at a faster rate than the underlying coating resulting in cracks in the film or alligator-like appearance. Solvent entrapment can occur with excessive film builds as well and is usually diagnosed bubbles or blisters in the film. The solvents in the coating become trapped when the outer film dries more quickly. Solvents can escape or evaporate eventually, leaving voids in the film or blisters if they are forced out by higher temperatures. With excessive film build, you can also see improper film development. Many coatings rely on solvent evaporation, chemical cure, or air to cure or dry as intended. With excessive film builds, you can alter the rates of drying or curing and ultimately affect the film integrity.
It’s Time to Get It Right!
Review the Technical Data Sheets and comply with our recommendations. We want you to look good, because you make us look good! When in doubt, contact Highland Technical Support! We are here to guide you through all of your coating challenges. We are waiting to answer your questions and provide expert advice on all aspects of the coating process. Contact us today!