Powder Coating Clinic: Measuring Film Thickness before Cure

Q. How can I tell if the powder film build is thick enough before I cure the powder coating? We coat a lot of square footage and we need to control our cost. We often put on too much powder to avoid light coating. I need to know what my uncured film thickness is.

A. I suggest you start by running regular trials to establish operating parameters that will provide a specific film build. A spray gun or guns operating at a specific output and position will provide coating thickness that is reasonably predictable. If you use standard operating settings and the equipment maintenance is good, the film build can be predicted within an acceptable range for most coaters. Some coaters use more sophisticated controls to meter the output of powder in grams per minute for more precise flow control and film build control. There are also a couple of thickness gages available that can measure film thickness before curing. In installations where a lot of powder is used a savings in film build of 1 mil could provide an excellent payback for a dry film thickness gage.

 

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Originally published in the November 2016 issue.