Tom Hunter-- Regarding Corten Steel structures... I saw a paper by Mr
Patrick Gallapher (referenced below) on Conservation ON-line. You may
want to contact him about your bird dropping problems, as they are
probably producing an acid which will lead to , if not already done so,
many types of interesting corrosion products. It appears he has a web
site on this very topic. Good luck.
Lisa Young,
Archaeological Conservator
Weathering Steel Sculpture
by Patrick Gallagher
Materials Preservation
http://www.best.com/~drrust[log in to unmask]