Anodizing aluminum
The environmental advantages of aluminum are widely acknowledged. Aluminum is one of the most durable and versatile of metals, offering improved mileage in automobiles by virtue of its lightweight and tremendous recyclability. According to the Aluminum Association, about one-third of all aluminum produced in the U.S. today is from recycled sources, saving some 95 percent of the energy required to produce aluminum from raw materials.
Source: Aluminum Anodizers Council (AAC). ACC is the international trade association of firms engaged in aluminum anodizing and whose mission it is to support members—and users of anodized aluminum—through education, advocacy and promotion.
Anodizing is an electrolytic process used to place a protective oxide coating on aluminum. This coating can be dyed a variety of colors before sealing, and after sealing provides a physically tough, wear-resistant surface with impregnated color. Stylmark is a Type II anodizing facility located in Minnesota. Type II anodizing is defined as conventional coatings produced from sulfuric acid baths.
Anodizing uses the base metal - the aluminum alloy - to create a thin, extremely strong and corrosion-resistant finish. The anodized surface is very hard and thus preserves and extends the life of the aluminum product.
Anodized aluminum finishes uniquely satisfy each of the factors that must be considered when selecting a high performance aluminum finish:
▪ Durability
▪ Indoor Color Stability
▪ Ease of Maintenance
▪ Aesthetics
▪ Cost
▪ Health and Safety
Anodized Aluminum Racking Marks
All anodized aluminum extrusion and parts must have electrical contact to the part to be anodized. Various contact types are used depending upon the size and geometry of the part being anodized. The electrical contact will leave racking marks on the finished parts. Racking marks include bolt marks, clip marks or thread marks. Most extrusions will include bolt marks, for this reason, Stylmark’s typical extrusion length is 2” over its nominal length, e.g., a 12 ft. extrusion measures to 146”. This way the user of the finished extrusion can trim the extrusion to size and have 12 ft. of useable, finished material. Other anodized aluminum parts, such as anodized sheet aluminum may also have bolt marks. Please verify allowable locations or contact Stylmark for options. Cut to length extrusions, fabricated or machined parts may be racked using clips. Although clips leave smaller rack marks, they are generally placed in least conspicuous locations possible as to minimize the appearance of the mark. It is important to communicate the critical surfaces & finish expectation to Stylmark so we can work with you to identify acceptable rack marks. Heavier materials, such as machined items or parts made from aluminum plate may require the electrical contact to be made in a tapped hole in the part. In this case, the rack mark will be on the threads of the tapped hole, where the bolt threads engage the part. If racking marks are a concern for the anodized materials on your project, you are encouraged to contact Stylmark, prior to placing your order, to discuss racking options.