ForMatter/Finishes/polish/Brushed (#4 / #6 / #8)
finish_polish_brushed

Brushed (#4 / #6 / #8)

polish · brushed · satin finish, directional brush, hairline, #4 finish, #6 finish, #8 finish

A directional grain laid down with a stiff abrasive belt or pad. Hides fingerprints, hides micro-scratches, shows a soft sheen instead of a hard reflection. The face of a stainless refrigerator, the deck of an Apple laptop, the side of a satin-finish wedding band.

Industry levels: #4 brushed (~150–180 grit, Ra 0.4–0.6 µm) is the standard architectural / appliance finish; #6 brushed (~220–240 grit, Ra ~0.2 µm) is finer, soft luster; #8 brushed (~320 grit, Ra ~0.05 µm) is near-mirror but still directional. Cut with abrasive belts, Scotch-Brite, or non-woven nylon wheels charged with grit. Direction matters — brush always parallel to the long axis of the part.

character — directional sheen, warm-cool gray, fingerprint-tolerant, reads as workmanlike.

Finish properties

  • levelbrushed
  • subcategorydirectional abrasion
  • Ra (µm)0.4
  • applies tometal

Second life

reversibilitymoderate — a polished surface can be re-roughened (sandblast, brush, etch) and a roughened surface can be re-polished; the substrate is preserved unless polishing-induced material loss is significant.
blocks substrate recyclingno
renewabilityvery high — polishing is the canonical maintenance operation for almost any hard surface; field-renewability is high for accessible surfaces, shop-renewability for everything else.

ASM Handbook Vol. 5 Surface Engineering; manufacturer abrasives literature (3M, Norton, Mirka).

Citations

  • url · https://en.wikipedia.org/wiki/Brushed_metal
  • standard · NAAMM AMP 504 — Stainless Steel Finishes (architectural metal grades #2B / #3 / #4 / #6 / #7 / #8).
  • book · Lefteri, *Making It* (Laurence King, 2012), 'Polishing' p. 282.