Anodized aluminum etching process and related apparatus

A process for modifying an aluminum article comprising:

• anodizing an aluminum article to produce first and second surfaces, each including an anodic layer;
• sealing the anodic layer of the first and second surfaces;
• advancing the aluminum article over a roller so that the roller contacts the aluminum article and so that an etching composition comprising sodium hydroxide is applied from the roller to the first surface to remove a portion of the anodic layer from only the first surface, thereby creating a plurality of protrusions to improve the adhesive strength of the surface;
• preventing the etching composition from etching the second surface of the article by maintaining the second surface out of contact from the roller.

A process for modifying unanodized aluminum sheets or webs comprising:

• providing an aluminum sheet or web;
• anodizing the aluminum sheet or web to produce a first anodized surface and a second anodized surface, each including an anodic layer;
• sealing the anodic layer;
• advancing the aluminum sheet or web over a roller so that the roller contacts the sheet or web, the roller at least partially submerged in a caustic solution comprising sodium hydroxide;
• and
• administering the caustic solution to the first anodized surface, but not the second anodized surface, with the roller to dissolve the anodic layer of the first anodized surface a pre-selected amount and to create a plurality of protrusions extending from the remaining anodic layer so that the protrusions and the remaining anodic layer provide an adhesion surface, wherein the aluminum sheet or web remains unsubmerged in the caustic solution so that the caustic solution cannot contact the second anodized surface.