| Metal Surface | ||||||||||||||||||||||||
| Iron and structral steel work | Priming metal surface | ||||||||||||||||||||||||
| Surface Preparation Different types of metals demand different systems in preparing the surface coating for protection and decoration.  Iron and structural steel work:  In major construction such as power stations, bridges, chemical plants, industrial buildings etc steel is used and needs adequate protection against corrosion, by a paint system. The performance and the protection provided by the paint system specified is dependent upon the standard or surface preparation, the best of which is considered to be blast cleaning. This, of course, is only normally economical if carried out at the steel fabricator’s works. On site, less efficient methods are often used, consisting of perhaps chipping, scraping and wire brushing, or the use of percussion needle pistols or on small areas, flame cleaning with oxyacetylene burners where it is decided to use blast cleaning. The metal should not be left exposed but must be coated with a holding primer immediately or within 1 hour of cleaning. Ensure the relative humidity is not above 80% before priming. Priming metal surface:  The correct choice of primer is essential. The following table indicates the recommended primer/primers for various surfaces, taking into consideration the conditions and requirements. It is vital that the correct primer be used on the correct metal substrate, considering the conditions and requirements of every substrate. |
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NOTE: In cases where alternative primers are shown, they are given in order of superiority taking into consideration their rust-inhibiting properties. |