Discolored Metallic Powder Finish
Q. We have a powder coat finish for our railing products that has been discoloring in the mountain states region (Colorado, Utah and Wyoming). The finish is textured metallic with a goldish tint, but it has been turning a darker color and rubs off upon touching. Is there anything that can be added to the powder coat or applied after the powder coating process that will inhibit UV rays and the discoloration of our product? A.J.
A. Metallic powder coatings are typically not UV-stable, and they can also be sensitive to handling damage or abrasion. Most suppliers of these products and reputable experts in the industry recommend the application of a clear coat over the base coat. Talk to your supplier to obtain a suitable polyester clear coat that is compatible with your “goldish” tint. Apply the base and partially cure it (about 50 to 60 percent). Then apply the clear coat and cure the two coats together. Be careful not to apply too heavy a coat with the clear to avoid loss of clarity of the base color. This will make your product perform better in sunlight and resistant to contact damage. Be aware that, even with a clear coat over it, you will lose some color and gloss over time.
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