Buffing & Metal Finishing Aluminum

Aluminum:  Before 1886 pure aluminum was so rare that it was considered a precious metal.  Then Charles Martin Hall developed a new electrolytic process, which is the basis for all aluminum production today.  Since then it has become it has become one of the most common and versatile metals in the world.  Aluminum is often blended with other materials to provide enhanced its properties whether improved machining, casting, forming, bending or buffing.  Because of the high strength and low weight aluminum is often used in the aerospace and transportation industries.  These same properties make it very useful in household products such as cookware, small appliances, utensils and packaging.

The versatility of aluminum makes it ideal to be used in several different forms that are commonly buffed: picture frame is extruded, airplane skin is rolled from sheet, automotive wheels are forged and complex engine parts are cast.  Any way the parts are made aluminum always provides high strength and light weight.  Although aluminum has relatively low melt temperatures (1200 °F), it is high enough to handle aggressive tangential buffing when necessary. 

For example, aluminum extrusions used for framing bathroom shower doors is a very competitive business.  Although the anodizing process produces a semi-bright finish it does not cover blemishes.  The die lines and flow lines produced in the extrusion process must be removed in buffing before anodizing.  These parts can handle the fast, high pressure tangential buffing to remove these lines.  Many times aluminum extrusions can endure the aggressive nature of even treated sisal buffs.

In the case of aluminum sheet or rolls a more gentle touch is necessary.  Rolls and sheet buffing is difficult enough because any defect jumps out of the flat surface unhindered by bends or contours of other shapes.  But in addition a buff that is too stiff may actually put small scratches into the relatively soft metal.  Therefore, roll and sheet aluminum buffing will often start with a mild mill treated cotton buff followed by a soft color buff.  Care must also be taken to apply the compound without forming lines on the part where it was sprayed.  Most often the compound is rolled on the sheet or sprayed on the buff with a low pressure gun to soften the compound lines.