HOME  > Surface Finishing Tutorial  > #119 Surface Adjustments - Brushed Finish
Surface Finishing Tutorial

#119 Surface Adjustments - Brushed Finish

Category :
March30, 2012

This is a method of pressing and moving metal brushes onto material surfaces to create directional lines, and is called "Hairline finishing".
Smaller scale brushed finishes maybe done with commercially available metal brushes, but larger scale brushed finishes employ semi-automatic system with wider brushes where the brushes pass over the workpieces or the workpieces pass under the brushes.
Other brush configuration is where the brush wire elements are arranged radially as brush wheels. This type of brush wheels can be mounted on buff lathes in a similar manner as paper buffs, and can create directional lines on surfaces. Table 1 shows the types of wheel brushes and finish types.

[Table 1] Brush types and finishing levels
Finish level Brush type Appearance
Coarse DIA. 0.5~0.8mm stainless steel or
steel wire brush
Approx. 50s
Medium finish DIA. 0.12~0.36mm stainless steel or
steel wire brush
12s~18s
Fine finish DIA. 0.05~0.1mm brass wire or
stainless steel wire brush
3s~12s
Gloss finish DIA. 0.05 or less brass wire or
stainless steel wire brush
Approx. 3s

There are a various diameters of wheel brushes and are used based on application purposes. There are types made of bent metal wire fixed to sheet steel. When used on buff lathes, varying wire lengths result in various finish effects.

In general, longer wire with circumferential velocity will result in dot effects, and lower circumferential velocity will generate scratch effects. With the wheel brushes, sharpness of the tips of the wire is critical. Pumice stones and bricks are occasionally pressed against the wheel brushes to remove accumulated oxides and metal powder.

A notable point on the brush finishing is that the wire fragments and powder of the bushes get ingrained into the surfaces of soft metal such as aluminum. If anodizing or chemical conversion processes are applied on such surfaces, partially blackened defects will result. Pretreatments to remove these ingrained fragments must be applied.

[Fig1] Hairline Finish, [Fig.2] Scratch Finish

MISUMI USA eCatalog