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Need to paint a Cor-Ten clock tower

September 3, 2009

Our company has been asked to paint a clock tower on a local university campus. This is a four sided clock on four 12" square steel uprights about 50' tall. The square uprights are supposed to be cor-ten, but are extremely pitted. I didn't think that cor-ten was supposed to pit. Is there any special prep required for painting cor-ten? Is there a specific paint system to use? I have looked at USS website which gives very little info about cor-ten.

Phil Kenney
sign contractor - Frostburg, Maryland

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My understanding is that Cor-ten is not meant to be painted and is in fact designed to weather/corrode with a low corrosion rate. The "pitting" you see is at least partly if not completely pre-existing -- i.e., it was made that way.

If there is absolute insistence that a coating be applied, get an expert to recommend a proper multi-layer paint system AND consider using it in conjunction with a passive or active corrosion suppression system based on buried zinc anodes.

Thomas Hanlon, Materials Engineer
aerospace finishing - East Hartford, Connecticut, USA
September 30, 2009

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Good grief! Forget it. I eat dim sum on Sunday mornings and my stomach turned over the second I looked at your photos! That looks like a job best left to a more gullible, volunteer victim!

Rod Henrickson
gunsmith - Edmonton, Alberta, Canada
October 2, 2009