Piano coatings lend the instruments their typically luxurious, high-gloss character. But there are a number of steps that have to be taken before the paint has been applied and the finish is polished. The basis of the piano coating is unsaturated polyester resins, which at BASF Coatings are condensed from alcohols and acids at 200°C. As with a cake batter, the paint producer gradually adds color pigments and additives to the resins. The additives ensure that the liquid paint does not sag when it is applied to vertical surfaces, such as the body of the piano. They also influence how quickly the paint gels and ultimately hardens.
To return to the cake-making image, BASF Coatings supplies the piano manufacturer the mixed "batter" and the manufacturer does the "baking" - applying, curing, sanding and polishing the coating. It takes up to 70 hours for a piano to be coated and polished. A grand piano even requires up to 120 working hours. The final coating has a film thickness of one millimeter, making it 200 times thicker than an automotive finish.
The robust finish of the housing protects the piano from damage and humidity - and gives it the familiar high-gloss, usually black, appearance, which is often used as a synonym for high-gloss, scratch-resistant surfaces.
When it comes to the sound of the instrument, the sound board is the key factor. The heart of the piano, made of wood, amplifies the vibrations of the piano strings. Since the sound board is constantly in motion, it is coated with a polyurethane paint that is crack-resistant and very elastic at the same time.
Other areas of application
BASF Coatings' piano coatings are not just used to provide high-gloss protection for musical instruments. For example, they are also used for luxury furniture finishes and for shipbuilding. In addition, up until a few years ago, piano coatings were used to coat wood trim in the automotive sector. However, ever since the requirements for paints used on vehicle interiors were changed, BASF Coatings has offered special paints for vehicle interiors in addition to piano coatings.