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springmaster
16-08-2011, 08:23 PM
Hi All
In a recent job that we done, we use galvanized sheets that were stock in the supplier for several months.
with the ducting already installed we see white spots, like a powder. We ask the supplier and He says that is humidity, but someone told us that is in english called "white rusting".
the supplier sugested that we can use paraffin 0on the sheets to clean this white rust, but we have almost the total of the ducts on site and installed.

The question is: is there any product that we can apply to clean this white rust?

your help would be much appreciated

Thanks in advwence

Brian_UK
16-08-2011, 10:57 PM
From reading elsewhere try this....
As far as removing the "white rust" phosphoric acid is very effective and is not too aggressive. Remember the protective zinc has been removed to some degree and a galvanic site has been created. the part should treated and painted or the damaged area cut out during fabrication.

Read also here...
http://www.finishing.com/0000-0199/009.shtml