PREPARATION FOR SURFACE TOLERANT COATINGS

Reference: 6/37

Valid from: April 14, 1987

Last reviewed: August 2020

PREPARATION FOR SURFACE TOLERANT COATINGS
The surface to be coated should be reasonably dry and free from contamination. Contaminants should be removed by an appropriate method before proceeding with further preparation. Hand brushing, chipping or mechanical cleaning will not remove grease and oil but will tend to spread it further over the surface. Localised grease or oil spots can be treated by using white spirit or other suitable solvent. Larger areas can be treated using emulsifying cleaners (water-soluble degreasing solvent), but where significant areas are contaminated, treatment should be by steam cleaning. Steam cleaning can also be used for rinsing after using emulsion degreasers.

Alkaline degreasing using soaps or synthetic surfactants should be avoided, or where these are used, extreme care should be taken to thoroughly rinse the surface. Alkaline degreasing residues may severely affect the bond performance of Corrocoat surface tolerant coatings. Dry accumulated dirt can usually be removed by dry bristle brushing. Scale should be removed by hammering, scraping, wire brushing and grinding which may be carried out either manually or mechanically.

Preparation standard should be to ISO Standard 8501-1 ST3 generally as follows:
Loose scale, rust and dirt are removed by thorough scraping of the surface using a hard metal scraper or needle
gun. The surface is then wire brushed vigorously. Loosened material should be removed during the operation so that the results can be observed. After cleaning the residues, the surface should have a faint metallic sheen.

On surfaces operating at temperatures up to 1350C, preparation to be carried out to higher standard ISO Standard 8501-1 ST3 .

Corrocoat surface tolerant coatings may also be applied to steel surfaces, blast cleaned to ISO Standard 8501-1 Sa1 or wet blast cleaned surfaces cleaned to a high standard, which have flash rusted.

On surfaces where firmly adhered light rusting only has occurred and no contamination is evident, surface preparation is not required except where elevated temperatures will be encountered.

Corrocoat surface tolerant coatings will overlap on to most aged coating systems, but loose or flaking coatings should be removed back to a firmly adhered edge.

Where corroded surfaces are contaminated with soluble metallic salts (usually after seawater service), evident by patches of the surface turning black and moist after scale removal, these salts should be removed by washing with fresh water or Chlor*rid and drying and re-brushing.

THE PERFORMANCE OF CORROCOAT PRODUCTS IS DEPENDENT UPON THE DEGREE OF SURFACE PREPARATION. OPTIMUM PERFORMANCE WILL ONLY BE ACHIEVED WHEN PREPARATION REQUIREMENTS ARE FULFILLED.