Parts makers these days are on the lookout for processes that are more environmentally friendly. One of the latest examples is in aluminum anodizing. Bonnell Aluminum, Newnan, Ga., a supplier of aluminum extrusions to the nonresidential construction market, is moving to an acid-etch process, said to be “greener” than the usual caustic etching it replaces.

Bonnell Aluminum

Bonnell says acid-etched anodic coatings have better finish consistency than those from caustic-etch anodizing. Acid etch is better at hiding imperfections in extrusion surfaces and nearly eliminates the appearance of visual streaks and die lines while giving a nice matte finish, a Bonnell spokesperson says.

The “green” aspect of the process stems from the fact that it conditions surfaces more quickly than acid etch, which reduces the amount of waste-sludge disposal by as much as 90%. In addition, the process enables the use of more recycled content in extrusion billet while maintaining a highly uniform finish, Bonnell says.

Edited by Leland Teschler