The problems with powder coating application over galvanized surface
Polyester powder coating over hot dip galvanized steel provides a high grade architectural finish to steel items with excellent atmospheric weathering characteristics.The powder coated product ensures maximum durability for steel components, which will generally provide 50 year+ rust free life spans in most architectural applications. Even so there are still some problems during this application.
Hot dip galvanized surfaces have been acknowledged as difficult to powder coating since the technology was first developed in the 1960’s. Industrial Galvanizers commenced research in this area in 1986 which culminated in the construction of a purpose built powder coating plant at its Hexham (NSW) site in 1988 in conjunction with its galvanizing operations there. The three main problem areas associated with the powder coating of hot dip galvanized steel products are:
- Pin holing of the coating
- Poor adhesion
- Incomplete curing of the polyester resin.
Industrial Galvanizers investigations into these problems, in conjunction with major polyester powder coating powder suppliers, resulted in the cause of these problems being better understood, and polyester chemistry and plant procedures and design to be modified to allow a consistent, quality assured polyester powder coated hot dip galvanized product to be supplied.