Problem Solving Forum
April 7 - April 14, 2017
When a specification calls for removing only loose coating from a masonry substrate, what methods are effective without damaging the intact coating that is left on the surface?
Zenith Czora of Durotech Industries, Inc. on
April 12, 2017:
I have learned based on experience and from the e ...read more I have learned based on experience and from the experts. Depending on the severity of the damage, you may choose to employ one or more the methods to prepare the surface for a new coating. 1. Scraping - Use shaped scrapers like triangle or oval shapes to get into corners and on rounded profiles. Take care not to gouge, score or otherwise harm the surface. Feather sand all rough edges with a medium, then fine grit garnet sand paper. 2.Wire or Bristle Brushing - Use a stiff wire brush, being careful not to damage the substrate. Once all loose paint has been removed, sand the surface with a medium then fine grit garnet sand paper. A stiff bristle brush is often a better choice than a wire brush, as it will not leave any metal swarf in the paint film, which may cause rust spots if the surface becomes moist. 3. Sanding - If the surface is just flaking slightly, you can simply sand the area with progressively finer grit garnet papers starting with coarse, then medium, then fine.