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Ask the Expert Question-and-Answer Archive by Ron Joseph December, 2007 Painting Over Powder Coated Frames in Hospital Environment Q: I just completed a project where I placed some murals in large window areas dividing patient rooms in and ICU unit. The window frames were powder coated a dark green. The murals are caribbean colors and the frames look hideous. I have permission to paint the frames as long as I do it correctly. I can't use toxic paints. Was wondering if I scuffed the surface if I could use pure acrylic paints with a water based clear coat over them. Please advise and thank you much. A: I believe you will have a good chance of success if you scuff the power-coater frames to a thoroughly matt finish and then use acrylic paints. Adhesion of one paint to another is enhanced if you can achieve both chemical and physical adhesion. In this case, I don't think that the acrylic will adhere chemically; therefore, you must achieve adhesion solely by physical means. That means using a relatively coarse abrasive paper, 320 grit or lower (coarser) and insuring that you do not leave any area unsanded. If the window frames are frequently washed with detergents, (since this is in a hospital setting) I'm not sure how well the acrylic with stand up. Therefore, you might consider priming the thoroughly sanded surfaces with a waterborne epoxy primer and then applying a waterborne epoxy or polyurethane topcoat in the color of your choice. I would prefer using a polyurethane as the topcoat, but the vapors given off by some poly's during the application and curing process can cause some people suffer serious breathing problems The only reason for recommending epoxy and polyurethane coatings is that the frames are in the ICU of a hospital and I expect that the surfaces are scrubbed down on a regular basis. The hospital's maintenance department can give you recommendations for epoxy and polyurethane coatings that have been approved for use in the ICU area. Good luck. Please send me pics of the finished frames and murals. Regards, Ron Joseph |