Effects of Relative Humidity during Surface Preparation and Painting
Author:
J.E. Yates
National Surface Treatment Center
Louisville, KY
Abstract:
Most U.S. Navy preservation specifications require surface preparation of steel substrates to a white metal or near-white metal cleanliness standard.  To mitigate the formation of flash rust and to optimize the service life of the entire coating system, the U.S. Navy requires the relative humidity in tanks to be kept at or below 50 percent during the entire surface preparation/paint application/paint curing process.  This essentially arbitrary requirement often necessitates the use of costly dehumidification and ventilation equipment. 
This study will examine the effect of various levels of constant relative humidity on the amount/rate of flash rust formation on a steel substrate and on the curing/performance of a selected coating system.