Polyester Durability

Polyester is hard, but correspondingly brittle. There are trade-offs involved in the real world of hard knocks. January 27, 2008

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.

Forum Responses
(Finishing Forum)
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.

From contributor C:
Pretty much any time you impact polyester, it will act as shattered glass, because it is something like 80% the hardness of glass. A good barrier cote may help. I find they always do.

From contributor J:
I always spray a coat of 2 part polyurethane first. This product bites into the wood a lot better than polyester. Typically I use Dupont Emron. It's the best and it doesn't turn yellow so fast.