What is “white rust” and how can it be prevented?
“White Rust” or Wet Storage Stain is formed because, zinc on newly galvanized steel is very reactive and quickly forms zinc oxide and zinc hydroxide corrosion products that go on to become the stable zinc carbonate. When galvanized steel is stacked damp or stored in wet boxes or shrink wrapped with no free flowing air, the zinc forms excessive layers of zinc hydroxide, otherwise known as wet storage stain. Most wet storage stain can be easily removed with a nylon brush. To prevent wet storage stain, store galvanized steel indoors and in such a way to allow free flowing air between each galvanized item. Why does the appearances of the coating sometimes differ from job to job and and will any difference affect how long it lasts? The chemistry of the steel is the main influence on coating thickness and appearance. Steel produced by the steel companies has a wide variety of chemistries, thus the different coating appearances. The galvanizer may also add several different additives to their
