The alloy you choose for your aluminum sheet naturally depends on your application. 5005 Aluminum sheet is often used when the material will be anodized and deployed in an architectural application like flashings, sills, curtain walls etc. Architects often specify 5005 alloy for anodized aluminum architectural metalwork.
The importance of using an anodizing quality (AQ) alloy when the aluminum will be anodized cannot be overstated. Anodizing is an electrochemical process that converts the metal surface into a decorative, durable, corrosion-resistant, anodic oxide finish. For more information about anodizing please see
http://www.anodizing.org/?page=what_is_anodizing. When anodizing, the metal you start with has a tremendous impact on the quality of the finished product that you will receive. Simply stated 5005 AQ alloy is formulated for a decorative architectural anodized finish. It allows for a more uniform and attractive anodized finish than other alloys.
Finishing 3003 Aluminum
A good example of why one should never anodize 3003 aluminum.
DO NOT attempt to anodize aluminum alloys like 3003 or 3105 if you want the finish to be attractive and consistent. These alloys will show imperfections such as structural streaks, cloudiness, blemishes, and EXTREME color variation.
Many people substitute 5052 for 5005. While 5052 can produce acceptable results, it has more imperfections and is more prone to color variation than 5005 alloy aluminum.
SAF is frequently asked, “Does SAF sell 5005 sheets in 1/4″ thickness?” Unfortunately, we do not. Flat material that is 1/4” is not technically sheet, it is plate. Plates are rarely used aesthetically and is normally used in structural applications. Because of this, plates are not manufactured for a perfect finish. If your application does not require good aesthetics, 5052 or 6061 alloys may be an acceptable substitute for 5005 aluminum.
Talk to your anodizer about your applications, and your expectations for the finish. They should be able to recommend an aluminum alloy for your application.