I have been spraying polyester now for almost two years on pianos. I have had varying success with different products, but one thing remains the same. When a large impact on a piece occurs, the polyester lifts slightly around the impact edge, creating a light colored barrier. This occurs if I use a polyurethane undercoater or not. I have seen the same problem with some of the manufacturers, but I have seen other brands that do not exhibit the same problem. I am wondering if it is operator error, or if there is a polyester product out there with better adhesion qualities.
From contributor D:
I would think of this as less of an adhesion problem and more of a flexibility problem. Polyesters are hard, as in brittle. "Large impact" is significant impact, but a more flexible marine grade polyester may survive the blow better. I can recommend Duro Coat from Hawkeye Industries for long term hold up under extreme conditions. Others may have other suggestions. Beyond that, tell your clients not to let their chandeliers drop on their pianos.