Stainless steel mechanical finishes: brushing

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By Richard Smylie | Apr 12, 2017
Selectively brushed stainless steel sill plate

GMN Automotive’s selective mechanical finishing capabilities include brushing, spinning, and texturing. Mechanical finishes are used to create contrast that can increase the perceived value of a part. In this blog, we will discuss the options available when choosing a brushed mechanical finish on metals such as stainless steel.

Brushed metal is produced by abrading the surface of a metal with a brushing wheel. Brushed finishes can be applied selectively or overall, in one or multiple directions. To create a selectively brushed finish, a screened-printed mask is applied to the area where the brush is not to come in contact with the metal, leaving only the non-masked areas to be abraded. Although selectively brushed stainless steel finishing is a very rare capability to come by, it has become one of GMN Automotive’s core competencies.

However, most finishes on metal – for both stainless steel and aluminum – are applied to the part overall. The most common finish used is a wet number four polish. The uneven brush strokes of a number four polish/brush highlight the metal’s brilliance on stainless steel. An ideal construction for stainless steel is one that requires the brilliance of a metal finish and superior structural performance. Common applications include automotive trim such as sill plates and arm rest trim.

Alternatively, the number eight mirror finish is highly reflective. This finish is created by treating the metal surface with a series of fine abrasives and then buffing it to create a mirror-like appearance. In contrast to the finish mentioned above, the number eight finish improves corrosion resistance. This is due to the polishing process that eradicates any cracks where particles can stick. Because of this corrosion-resistant feature, the number eight finish is commonly used for mirrors and wall panels.

In addition, brushed finishes can be combined with colors to add even more contrast and light movement to the aesthetic of the part.