Well then. Maybe I will start buying black sintra. I don't think it's the paint job. I start with primer, and add several thin coats of the colors I am using. Each of them is the same brand, Krylon for plastics. I then use a Krylon matte clear coat, which I have sprayed on in thin coats. Usually I spray 4 or 5 coats.
I must just be unusually hard on my armor. Maybe it's getting chipped and scuffed from being packed and transported to events. I just don't know at this point.
All these ideas are great! Keep them coming.