SURFACE PREPARATION: The surface is cleaned of oil, dirt and grease by means of solvents or emulsifiers. Rust and scales are removed by mechanical means like scrapping, wire brushing and rubbing with emery paper. Sand or grit blasting is used wherever possible to obtain a completely clean surface. Chemical methods using phosphating chemicals, rust convertors, etc. may also be used. Immediately after cleaning the surface a primer coat is applied.
PRIMER COAT: The primer coat which protects the substrate is available in a choice of anticorrosive pigments such as zinc phosphate, zinc chromate and red oxide. For highly corrosive environment a zinc rich primer is recommended. Protecto-Corogard 10 and Protecto-Corogard 40 are mixed thoroughly and applied evenly by brush or spray. Details of the primer coat are given in Table 3.
TOPCOAT: The primer coat is allowed to dry for 2-3 hours. Two topcoats are then applied over it keeping a gap of 2-3 hours between the coats. Details of the matt, glossy or coal tar modified (for underground structures) topcoat finishes are given in Table 3.
APPLICATION ON CONCRETE
Dirt and grease deposits are removed from the concrete surface by wire brushing and solvent/detergent cleaning. An acid wash using 5-10% hydrochloric acid is then given followed by thorough washing with large quantities of water. The surface is allowed to dry thoroughly. Small cracks and depressions in the concrete surface are filled up with a paste made by adding silica or talc to a mixture of Protecto-Corogard 10 and Protecto-Corogard 30. Three coats of Protecto-Corogard mixture (glossy or matt) are applied by brush or spray, keeping a gap of 2-3 hours in between coats. Details of these coats are given in Table 3.
APPLICATION ON F.R.P. AND WOOD
The surface is thoroughly cleaned and leveled with compatible leveling compound or with a putty made by adding silica or talc to a mixture of Protecto-Corogard 10 and Protecto-Corogard 30. Smoothen the surface with emery paper. Two or three coats of Protecto-Corogard mixture (glossy or matt) are applied by brush or spray keeping a gap of 2-3 hours in between coats. Details of these coats are given in Table 1.