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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
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Type 2 Black Anodizing Discoloring
My company makes motorcycle exhaust tips and we are having trouble with them staying shiny black over time.
The tips are 6061 aluminum, machined, polished, bright dip black anodized type 2, laser engraved with our logo, and then teflon coated.
The teflon coating eliminates problems we were having with UV discoloration. When left in the sun, the exposed sign would turn brownish whereas the rest of the part would remain black. When running on a bike, however, they are exposed to a constant heat and over time (2 weeks to a month) they are turning a shiny purple color.
The look is extremely important. Going to type 3 anodize I was not able to get the same shiny clean black look that we want. Ceramics and other finishes, same problem. Is there a way to get a type 2 black anodize that won't discolor from the heat? I've read about teflon impregnating or sealing. Is this something done instead of a standard nickel seal?
Procurement for company - Santa Ana, California, USA
August 25, 2010
Organic Black Dye will fade with temperature. The anodic coating will crack with temperature.There is no fix to correct the problem of cracking and fading.
Robert H Probert
Robert H Probert Technical Services
Garner, North Carolina
August 27, 2010
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