MAR 26, 2015

Flash rusting – what it is and how to prevent it

Water jetting is an effective method of surface preparation, widely used on a wide range of materials including metal and stone.  Water jets clean dirt, they blast away grime and they can also cause flash rusting if you’re not careful, especially if you attempt to clean metal surface areas. 

Flash rusting appears within minutes of metal being cleaned, it changes the way the surface of the metal looks and leaves a bronzy, rust-coloured appearance behind.  Virtually all steel surfaces will show traces of flash rusting within as little as half an hour after cleaning and visible signs of rust will quickly become present.

Flash rust causes

Flash rusting is normally caused by metals being exposed to corrosive environments. It’s more likely to happen when wet surfaces are left to dry naturally or freshly blasted surfaces aren’t coated quickly enough. Flash rust is also caused by tiny iron particles falling onto metal surfaces. They stick to the surface area and quickly start to rust. The longer you leave the rust untreated the greater chance there is of causing permanent damage and creating a much larger problem.

Treating flash rusting

You can remove flash rusting by washing, rubbing and treating the surface area as soon as possible.  Specialist rust cleansing liquids can be used to remove all traces of particles and steel wool is another common method used to scrub rust away from metal. Once the metal is rust-free the surface area should be treated with a rust inhibitor and given a protective coating to prevent the problem from reoccurring.

Ways to avoid flash rusting

One obvious way to prevent metal surfaces from being exposed to flash rusting is to use other methods of cleansing apart from water jet blasting. Water pressure is a good tool for cleaning purposes but blast cleansing using specialist media should help to reduce the risk of rusting, particularly if the area is treated, painted and prepped straight afterwards.      

As always, we have a range of blasting abrasives suitable for different types of abrasives at Blastrite. For the sake of convenience, you can find them all here http://www.blastrite.co.za/products/blasting-abrasives   

Created on 26th March 2015
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