The surface cleaning and preparation are processes to remove oil, grease, old coatings and surface contaminants and control the size, flatness, and/or roughness of the surface for coating or further finishing. These processes are essential for the success of any protective coating scheme.
There are three basic methods of removing contaminants: Chemical Cleaning, Abrasion and Degreasing.
- Chemical Cleaning is popular for preparing metals. It includes treatments which etch the surface to form highly adhering oxides, or deposit complex inorganic coatings.
- Abrasion includes sandblasting, vapor honing and use of abrasives cleaning and finishing materials. The dimension of components needs to be watch closely when using abrasion methods.
- Degreasing often cleans the surfaces with either a hot alkali solution or solvent vapor. To use either method, surfaces must be free of rust, paint and mill scale.