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Does Acid/Alkalinity exposure to galvanized surface simulate flooding exposure?

March 31, 2008

I am researching possible flood exposure to two 2007 motorhomes that have a zinc/galvanized coating on undercarriage metal surfaces. The two motorhomes have been shipped from the manufacturer (Indiana)to two dealers, one on the east coast (New Jersey), and the other on the west coast (California). They both display what the galvanizers association calls heavy wet storage stain. This apparently happens when the galvanized coating has not passivated by forming its protective coating known as the zinc patina.

My question is... can exposure to strong acid/alkalinity produce the same results?

Thank You,

Dennis Myhre
researcher/investigator - Branson, Missouri, USA

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Personally, I doubt it, Dennis. First, there looks to be some evidence of rust of the underlying steel, and alkali will not cause steel to rust. Second, acid attacks the corrosion products (oxides) first because they are more soluble (that's how metal polishes work). My personal opinion -- not a professional opinion -- is that this is water damage.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
April 3, 2008