Preparation and Protective Painting of Structural Steel Available to Purchase

Introduction The post‐war period has seen great changes in the protective treatments applied to structural steel. Whilst corrosion scientists had urged for many years that removal of all rust, scale and surface contaminants before painting was essential to obtain full value from paint treatments, it was generally agreed until recently that to do so was impractical or ruinously expensive. Because the performance of the best available paints was not always adequate on poorly prepared steel, metallization treatments, designed to isolate steel by a complete cover of non‐ferrous metal, were sought, Galvanizing on pickled steel has been practised for many years on light gauge metal. For heavier sections metal‐spraying was developed, but to make this a viable process, mediods for cleaning the steel surface were essential. The grit‐blasting technique perfected for preparation for metal spraying began to be adopted as preparation for painting. However, progress was limited by gross variations in efficiency, and thus in costs, doubts about the type of surface desirable for paint and lack of definition of the bonus in performance to be expected from good preparation.