Overcoating Lead-Based Alkyd Paint on Steel Penstocks: Practical Experience

摘要

While it remains axiomatic that good surface preparation is critical to the success of a coating application, for overcoating applications it is equally crucial to select overcoating systems with utmost care, paying particular attention to their chemistry, physical properties, performance history, and intended service environment. This article describes key technical attributes of an inno vative high ratio calcium sulfonate alkyd (HRCSA) overcoat system, and how these attributes allowed for the successful overcoating of a lead-based alkyd paint system on a penstock exterior at a Canadian hydroelectric facility, using only 5,000 psi pressure washing for surface preparation. The case history provided outlines how the coating system also lent itself well in helping to solve different crevice corrosion issues.