Liquid Coatings Clinic: Correcting Liquid Adhesion Issues

Q. I cannot get the desired adhesion of my coating to my part. What should I look for to fix this problem?

A. To optimize coating adhesion to the part, there are many things to consider, but I would start with the part preparation. All coatings need a clean and well-prepared surface to get the best adhesion to the surface as possible. Of course, there are many ways to prepare the surface. Options include a simple wipe down with a solvent removing soils that may interfere with the adhesion to a mechanical cleaning with sand or shot, creating an anchor pattern that gives the coating a clean and expanded surface to adhere to. There are also many chemical treatments that can etch or convert the surface to improve adhesion. Make sure you are giving your coating the best chance of success to adhere to a part by assuring the surface is well prepared for your coating choice. 

Another consideration is the coating selection. Make sure you have selected a coating that is designed for your application. If you are applying a coating without a primer and have not selected a direct-to-metal (DTM) coating for you application, you may need to apply a primer to enhance adhesion. Not only will the primer give you a better bond to the surface, but it will provide a subsequently better adhesion between the topcoat and the primer.

 

 

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Originally published in the January 2017 issue.