Metal finishing Q&As since 1989
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Aluminum facade finishing
Hi, I am Gustavo Castillo from Mexico. The company for which I work, a metal objects manufacturer, has been given a very interesting project in an area that is not our main field of work, but in which we want to enter. This project will help us do so, but we are limited in our experience and don't want to fail, therefore, I refer to the specialists for help.
The project consists of covering a biulding's facade with aluminum parts. These parts are 75 cms wide concave hexagons. Each part will be anchored to the curved walls of the building, forming some kind of armor over it.
The main issue we have is with the finish of these parts. The architects want them to be just like mirrors, on their concave side, long lasting (40+ years) with the least maintenance possible. We are exploring chroming, polishing, anodizing, painting. Each with its pros and cons, but we want to ask you, the industry experts, if there is any process you would recommend, perhaps a different process from the ones I just listed, some kind of coating to reinforce any other process, a new high-tech chemical we should use, etc.
Your help will be very much appreciated.
Regards,
Gustavo
metal objects manufacturer employee - Mexico City, Mexico
August 25, 2009
Hi, Gustavo. Forty years may be an unrealistic expectation for an aesthetic, reflective metal finish. But I'd probably suggest bright dipping and anodizing, followed by a clear coat.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
August 25, 2009
Gustavo,
Though I agree with Ted in that bright dipped and anodized aluminum may be a very aesthetic answer at the begining I must also warn you that once the look is gone (two or three years, perhaps more) this base material and finish is very difficult or impossible to restore. On the other hand, Bronze and brass have for centuries been chosen as the best long lasting surfaces exposed to outdoor environments. They tarnish but can be easily polished back to as-new condition.
Monterrey, NL, Mexico
August 29, 2009
First of two simultaneous responses --
Many thanks Guillermo, how can I then get a silver mirror polish in bronze or brass? is there a way toprotect them from tarnishing? some kind of coating?
Thaks
- Mexico City, DF, MExico
September 2, 2009
Second of two simultaneous responses --
Forget aluminum try stainless steel or titanium.Even clearcoated aluminum can't be useful for that type of application(maybe it can last up to 5 years)Hope it helps and good luck!
Goran Budija- Zagreb,Croatia
September 3, 2009
Again, 40 years is a very long time. But nickel-chrome plated brass, as used on yachts and fine sailing ships, is a beautiful finish that can last for decades.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
September 8, 2009
September 9, 2009
Gustavo,
On www.atomium.be ,you find a building with 9000 square meters of wall cladding (pity photos are so poor and no one else is allowed to edit photos).
Originally in 1958 an aluminium wall cladding , bright dip + anodized
, but lost its mirror effect after some time.
Finally, after decades of dull appearance, was refurbished in 2003 with new cladding :stainless steel 316 electropolished and passivated. This has a good chance to keep its mirror aspect for 40 years and more. In Europe, this combination is the standard for everlasting wallcladdings.
Wish you success.
Kind regards,
Marc.
- Diksmuide, Belgium, Europe
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