As published in the March 2020 issue of Products Finishing
APC has an extensive polishing and buffing department, one that has been a mainstay of the shop for more than 60 years. Castings with parting lines of sufficient size may need to be polished with an 80-grit abrasive and then finished with a progressively higher grit sequence of polishing abrasives, something which APC has gained industry notoriety for perfecting. Polishing witness marks can also be removed with a range of buff treatments and compounds, and the treatments vary in texture and stiffness, depending on the application/use and the buff compound materials that actually affect the finishing.
“Copper Buffing” is a metal finishing strategy APC uses which adds two extra steps to the finishing process, but produces the smoothest finish for chrome plating product. With the copper buffing approach, Macary says a magnesium, zinc or aluminum die casting would first get polished and buffed, followed by a second step to deposit a thick layer of copper. The third step is to buff the copper and then nickel-chrome plate the part, a process that produces what Macary calls “Show Chrome.” Click here to read the complete article.