Tea-staining is a discolouration of the surface of stainless steel caused by mild corrosion  This corrosion is cosmetic only and does not affect the structural performance of stainless steel. Having recently attended an ASSDA seminar on Preventing Coastal Corrosion, I would like to share some information on how to get the most out of your stainless steel and keep it looking shiny and new - Why is Stainless Steel Incredible?

There are several precautions you can take to help prevent tea-staining occurring which include choosing the correct grade of stainless for your application (Guide to selecting the correct grade) , ensuring the smoothest possible finish of your stainless steel (for more information, refer to our DOs & DON’Ts Guide for Stainless) and adequate cleaning or washing of the installed product (see our Cleaning and Maintenance Guide). It is important that residues and salt deposits are regularly washed from your stainless and an occasional rain washing is sufficient in many applications. A minimum of 316 marine grade stainless steel should be used in high corrosion or coastal environments and as a general rule, the smoother the finish of your stainless steel, the better it is able to resist corrosion.

If tea-staining does occur, the Nickel Institute recommends application of a phosphoric acid gel to remove the staining and restore the surface of the stainless steel. For this purpose, Anzor Fasteners stocks Grunt Emergel, which is a phosphoric acid based gel that is excellent for this type of treatment.

Grunt Emergel is a simple to apply, then wash off product, that can easily remove tea-staining in most applications and eliminate the necessity for mechanical removal of surface corrosion,  which can be time consuming and expensive. Ensure you wear gloves and safety glasses when using Grunt.  Grunt Emergel is a gel, so you can leave it on the surface for 15-30 minutes to help remove really nasty stains before scrubbing clean the stainless steel and then washing off.