You can stain a fiberglass door, and you’ll be pleased with the result. But be aware: You don’t use the same stain or process for staining on fiberglass that you use on wood doors.
Unlike wood, fiberglass doors, which you can get embossed so they look like wood, don’t absorb stain. So you must use a gel stain on fiberglass doors, and cover that with a clear topcoat.
Many of the door manufacturers sell kits that contain both stain and finish.
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