• Rusted steel should be painted to prevent further rusting.rusted background image by AGITA LEIMANE from Fotolia.com
  
  While some choose to paint steel because they want to alter the color, others are forced to paint the metallic surface to protect it from rust. Whatever the reason, steel should be painted a particular way. Because steel is ill-suited for adhesion, it requires thorough preparation or it will quickly shed its painted finish.
  
  

Aesthetics

• Steel often stands out from surrounding surfaces, so many homeowners choose to paint steel surfaces to help them to blend in better. Support beams in finished basements are a prime example of this.
  
  

Rust Prevention

• Galvanized steel surfaces are coated with a layer of zinc that protects them from rust, but steel that hasn't been galvanized will eventually rust when exposed to air and moisture. In these instances, steel should be painted, but first the steel requires a red oxide or zinc chromate primer that will protect the steel from future rust outbreaks.
  
  

Rust Sealing

• Once steel surfaces begin to rust, the rust will continue to spread until the entire surface is destroyed. Rusted surfaces can be salvaged, though, with the appropriate types of coatings. Existing rust should be removed with a wire brush prior to application of the coating. Then a coat of red oxide or zinc chromate primer is required to seal the existing rust and prevent recurrence.
  
  

Other Considerations

• Unlike wood surfaces, galvanized steel is ill-suited for paint adhesion. It must be coated with a galvanized metal etching primer that will abrade the surface to promote adhesion. Never paint over galvanized steel without first applying an etching primer, or the paint will eventually flake off and peel.