Flash Rusting from Water Bourn Paints

Flash rusting is a significant problem for all water borne paint, especially over steel.

What Is Flash Rusting?

Flash rusting is corrosion from steel bleeding through a coating creating a stain within hours of the coating application. Long term corrosion is not flash rusting. This occurs when a thin film of water resides on the surface of steel for a brief period of time causing corrosion to take place. The corrosion products are often soluble and can migrate within a coating to produce a stain.

Flash Rusting on Metal
Flash Rusting on Metal

Flash rust is very common in water borne coatings since they have the two primary requirements to allow corrosion; oxygen and water. If either water or oxygen is not available, the metal corrosion rate will be retarded. Since water borne coatings are applied in a thin film, this allows oxygen to readily permeate through the coating. Henceforth, flash rusting is a common problem.

It usually occurs when there is high humidity, low temperatures, high wet film thickness, another cause is low coverage over a higher blast profile.

Rustoleum Noxyde Metal Cladding Paint
Rustoleum Noxyde Metal Cladding Paint

Our full range of metal protective products can be found on our website here.

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Do you require more information on flash rust solutions? Contact our technical team on 01462 421333 to discuss your requirements today. Alternatively, email our team on info@promain.co.uk.