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  for Metal Finishing since 1989
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Keeping micro-mirrors shiny outdoors

September 28, 2011

Gentlemen -- I'm looking for advice on making shiny surfaces that are robust enough for outdoor deployment. I have a process for carving tiny mirrors into sheet metal such that sunlight glinting off the surface produces a holographic image. Currently I'm working in various aluminum alloys but could move to steels, titanium, etc. For an art installation I'm going to mount these on building exteriors, and I'm concerned about long-term corrosion-resistance, durability, and maintainability. I have some test pieces that have done well outside for 3 years, but urban conditions will not be so favorable -- skin oils and cleaning chemicals will attack the reflective surface and vandals may scratch aluminum. I'm looking for recommendations for treatments, coatings, platings, or alternative alloys that will keep a surface shiny even when touched, washed, and weathered. Chrome & electroless nickel are obvious candidates -- what else? BTW, I only need to preserve the carved reflective surfaces; the remaining surface of the sheet metal could be left to oxidize, patinate, etc. The reflective surfaces can be as small as the grooves in a vinyl record (50 micron), so I think re-polishing in the field is out of the question. All ideas appreciated.

Examples at www.zintaglio.com

Matt Brand
artist/technologist - Cambridge, Massachusetts, USA