Severe deterioration of metal surface is noticed over vertical legs, horizontal channels and roller supports of this conveyor structure which is due to continuous exposure of saline salts and condensation, in-spite of having conventional paint over them. Existing paint was unable to prevent the ingress of these corrosive substances and in turn allowing the underneath corrosion that resulted in blistering and localized deterioration of metal surface
Newly fabricated roller supports and rest of the conveyor structures were blast cleaned with coarse copper slag to achieve “Near White Metal Finish of Swedish Sa2.5 standard” along with an average 50 microns surface roughness with due checking of salt freeness. All these three aspects i.e., cleanliness, roughness and contamination freeness will directly influence the adhesion of coating in terms of polar-polar, chemical and mechanical interlocking with surface of conveyor.
Over very thoroughly prepared surface, ProCoat coating system was applied directly with very thorough wetting coat with high hand pressure application followed by low hand pressure coat with synthetic roller carried out to meet the recommended thickness of coating.
All desired quality checks such as “surface contamination”, surface cleanliness, surface roughness were checked with Elcometer instruments, and after application of coating, wet and dry film thickness checks alongside coating integrity check with Elcometer instruments were carried out to ensure complete integrity of ProCoat coating in all respects
In a phased manner, over & top of the fully and thoroughly completed areas of ProCoat coating, a top coat of dark grey colour weather resistant polyurethane was applied by brush and roller to the desired thickness levels. The purpose of this top coat is to maintain colour code as per the customer’s in- dustrial norms, as well as to give additional protection from weathering apart from the saline corrosion protection offered by ProCoat Advance Polymer Coating System.