Eco-friendly anodize

Introducing acid etch to customers and employees
By Tammy Schroeder
September 22, 2009

The Grand Rapids (Mich.) Ballet featuring secondary aluminum with eco-friendly anodize. Photo courtesy of Tubelite Inc., Walker, Mich.

Traditional caustic etch (upper left) versus eco-friendly acid etch.

Linetec’s anodize line.

Unlike a painted finish, anodizing highlights aluminum’s metallic appearance. An integral part of the substrate, the anodic coating results in a hard, durable substance providing good wear with minimal maintenance. It is highly resistant to abrasion, temperature, corrosion, humidity, warping and the ravages of time. Anodized aluminum is an inert material that is not combustible, entirely recyclable and poses no health risks.

To achieve these traits, etching is an important step during the anodize process. Etching is designed to dissolve a thin layer on the surface of the aluminum to develop a smooth uniform finish. Linetec, Wausau, Wis., recently changed its etch chemistry from conventional caustic etch to a more eco-friendly acid etch process.

As architects' and building owners' demand for recycled aluminum has increased to meet green building goals such as those outlined under the U.S. Green Building Council’s Leadership in Energy and Environmental Design program, so too have manufacturers' interests in providing them with an aesthetically appealing, high-quality finished material.

Anodized aluminum is 100 percent recyclable and can be stripped to raw aluminum through the conventional etch process and then painted, or re-anodized. Aluminum can be recycled and re-used again and again without losing any of its characteristic attributes: There is no loss of quality in using recycled aluminum.

With eco-friendly anodize, the resulting matte finish reduces glare in bright sunlight, an attribute associated with increased productivity and comfort for occupants. Interior comfort and recycled material content are recognized by green building programs such as LEED.

To modify the etch chemistry at Linetec, one new process tank was installed for each anodize line. The material moves through the anodizing process facilitated by an automated control system. The computer-controlled hoist system guides the material through the process, eliminating manual variations in pre-cleaning, etching, anodizing, coloring or sealing. This ensures a consistent and durable finish on every load.

Coupled with the chemistry and equipment to offer eco-friendly acid etch, Linetec’s employees were trained to identify and assess the new variations associated with a different process, including the new gloss levels and color ranges. Linetec also has been educating its customers and helping them inform architects about the advantages of the new process.

The author is national marketing specialist, Linetec, Wausau, Wis.