Hydrogen gas generated during electrodeposition discharges electricity.
Electrical energy (sparks) of the discharge causes the paint film to partially harden, which leaves pinholes after baking.
Q:
- High coating voltage
- Low bath temperature
A:
- Hot-dip galvanized sheet steel is most likely to form pinholes due to outgassing, so be careful.
- To counter this problem, the most effective way is to increase the solvent quantity for improved paint film fluidity during baking and, at the same time, to reduce the coating voltage.
- Emergency measures: Raise the bath temperature and reduce the voltage.