Cleaning

• Dirt and oily residue will inhibit paint adhesion. If the paint is peeling from your door, it may be because you failed to properly wash the steel prior to application.
  
  

Priming

• If you apply paint directly over a steel door, peeling will inevitably ensue. Metallic surfaces are ill suited for paint adhesion and require a base coat of a particular type of primer before they will accept painted finishes.
  
  

Etching

• Because steel is a nonporous surface, it is ill suited for paint. Unfortunately, ordinary primers will not bond to durable steel doors. You must pretreat the door with a special acid-based, galvanized metal etching primer before you paint. If the paint on your door is peeling, you may have chosen the wrong type of primer.