Q. I have a unique question for which I need some advice. It pertains to the proper preservation of an original I-beam from the 9/11 World Trade Center site. I have been asked to make an honorable artistic memorial for exhibition on the 10th anniversary of the tragedy. For the memorial, a section of the I-beam will be publicly displayed inside an airport, and it may be an open display able to be touched by the public. When the I-beam was in storage, it was placed into an oxygen-purged tent for a few years. The TSA recommended we find some way to clean the beam but leave the original finish intact. Who knows what chemicals, debris, toxins and human parts are on the surface? We thought of a liquid cleaner/soap but suspect this will cause more rusting after application. Any recommendations for cleaning, preservation and processing while retaining the original finish? Thanks! B.B.
A. Since the WTC I-beam will be touched by you, your staff and the public while the memorial is being built and is on display, it must be cleaned to remove any contaminants and toxicants. To preserve the original finish or look of the artifact under those conditions, it must be coated with a flat, clear finish. The best choice for that purpose would be either a flat, clear two-component polyurethane or an epoxy coating. Since the clear finish will be flat (no gloss), it will be practically imperceptible.
I recommend the following procedure for preserving the appearance of the original finish on the WTC I-beam:
1) Clean the artifact using a hot aqueous detergent solution applied by spraying to remove toxicants and oily soils. The cleaning solution should contain a rust inhibitor to prevent further rusting.
2) Spray rinse using clear water containing an aqueous solution of a rust inhibitor, if it is not already in the cleaner.
3) Dry thoroughly.
4) Coat immediately after drying using either of the aforementioned flat, clear coatings.
The cleaning solutions are available from industrial metal pretreatment suppliers. The coatings are available from company stores of the major paint companies.