Substrate Galvanised Steel
Substrate Galvanised Steel

Substrate Galvanised Steel

Galvanised steel is coated for two reasons…

  • For decoration, that is aesthetic reasons,  to a different colour and gloss
  • To enhance corrosion protection in locations where galvanizing might be vulnerable

There have been many failures of coatings over galvanized steel. A&I Coatings has done extensive research into this phenomenon and has reached the following conclusions…

  • It is important to have enough film thickness to have a barrier coating, that is a coating that is impermeable to oxygen and moisture vapour.
  • It is important to have a corrosion inhibiting primer such as a zinc phosphate.
  • The galvanized surface must be clean and free from oil, grease, dirt, corrosion products and especially soluble salts.
  • Galvanised steel must be whip blasted, or mechanically abraded before coating
  • The A&I Specifications following are based on the above premises.

Effective coatings are available both in solvent borne and water borne vehicles, depending on specification, customer choice, green star requirements etc.