The electrochemical link between zinc and steel is sufficient, to provide rust prevention on small damages on zinc coating. But client may face necessity to renovate damages caused by cutting or welding, or other significant damages.
In such a case different methods may be applied. Irrespectively of the chosen method, it should be ensured that coating thickness in the damaged place would be by minimum 100 µm. European and international standard ISO 1461 allowing small renovations recommend bu thermal zinc spraying or by a suitable zinc-rich paint.
Renovation methods of damaged zinc coating:
Brush the damaged place with metal brush and apply several coatings of zinc rich paint, until the coating by 30 µm exceeds the original zinc coating.
Brush the damaged place with metal brush, heat it with gas flame and apply in the needed thickness appropriate alloy by soldering.
Clean the damaged place with shot blasting and spray zinc rich paint, until the coating by 30 µm exceeds the original zinc coating. This method requires specific equipment.