Problem Solving Forum
April 25 - May 1, 2011
When specifying coatings for maintenance repainting of structural steel, under what conditions is it acceptable to settle for a surface-tolerant system, and when is such a system unacceptable?
Selected Answers
From
Antonio Tolotto of Boat S.P.A. on
April 28, 2011: First of all, I l ...read more
First of all, I look at what the specification says. If there is no specification and I must choose, my idea is to avoid poor surface preparation for immersion service. Second, I try to use this system for maintenance of external, non-immersed surfaces, providing a general deep cleaning, because the main quality of good surface-tolerant coatings must be good adhesion on old coatings and on steel, of course. It is recommended to use such coatings for the maintenance of interiors, since they generally have high solids. Last, but not least, I try to choose a reputable supplier, because very often surface- tolerant coatings are three wonderful names telling nothing.
From
M Ehab of North Valley on
April 7, 2012:
If the structure is ...read more
If the structure is complicated, better go for a surface-tolerant anticorrosive. In all cases, epoxy mastic is the best surface-tolerat coating. It is best is to apply an epoxy mastic anticorrosive with aluminium or glass flake or micaceous iron oxide flakes at DFT of 150 microns (6 mils) minimum. Some epoxy surface tolerant coatings are designed for M+R (i.e., can be applied by Brush at higher DFT). Keep in mind that improved surface treatment (blast cleaning to Sa 2½) will improve the performance.