Brushed Stainless Steel Finishing

Brushing and mirror polishing are the surface finishes we run in our own workshop, which is why this page can be specific about brushing instead of describing it in the third person. It is also the finish buyers most often get wrong on the drawing — “brushed stainless” can mean anything from a coarse 80-grit grain to a fine decorative line, and the difference shows the moment two panels sit side by side.

What brushing actually does

Brushing is an abrasive process, not a coating. An abrasive belt or wheel is drawn across the surface in one direction, cutting a shallow, parallel grain into the metal. Because the grain is cut rather than deposited, it does not flake, chip or peel, and it hides the small handling marks that a mirror polish would amplify. On stainless it also gives the surface a slightly matte, low-glare character that reads as industrial rather than domestic.

What it does not do is protect the metal. Brushing removes the passive chromium-oxide layer that makes stainless corrosion-resistant, so a brushed part is passivated afterwards. That is a chemical step — passivation and electropolishing both run on the audited partner line that handles our other chemical finishes — we specify the method and the acceptance evidence on the drawing and check the result on receipt.

Grades: the grit sequence is the specification

“Brushed” without a grit is not a specification. These are the finishes we run and what each one looks like in service.

If the drawing says only “brushed stainless”, we will ask which of these you mean and put the answer on the drawing before the batch runs, because it is not something that can be corrected afterwards without reworking the surface.

Grain direction: the detail that decides whether a set looks made or assembled

On a single flat panel the grain direction is hardly noticeable. On an assembly — a door and its frame, a run of cabinets, a two-part housing — the grain direction is the first thing the eye picks up, and mismatched grain is what makes an otherwise sound product look cheap.

• Vertical grain is the most common choice for tall panels and doors; it reads as stable and is the convention for architectural work.
• Horizontal grain suits wide, low panels and is frequently used on drawer fronts and fascia panels.
• Grain across a bend must be planned at the drawing stage: the grain runs through the bend in one direction, and the outside of the bend takes the grain differently from the flat. If the part is formed after brushing, we agree which grain orientation gives an acceptable result at the bend.
• Matched joints — where two panels meet — need the grain agreed across the joint. We set the grain direction from a datum on the drawing so that panels brushed in different batches still meet correctly.

Because brushing is in-house, we can brush a set of parts as one batch with the grain direction set from a single datum, rather than finishing panels separately and hoping they match. This is a practical reason buyers move brushing to a fabricator that also forms the parts.

How we agree the appearance standard

Surface finish disputes come from judging the same panel under different light. So the acceptance standard is agreed before production rather than argued about after delivery:

• An approved sample panel is kept as the reference for the batch, and both sides hold a copy or a photograph with the agreed lighting noted.
• The grain direction and grit sequence are written on the drawing, not left to the shop floor.
• Inspection is visual against the approved sample under agreed lighting at an agreed distance — not at arm’s length under office light, which passes almost anything.
• If your incoming inspection grades appearance, tell us the standard you use and we will confirm before quoting whether we can hold it.

Brushing compared with the alternatives

What to put on the drawing

• Grit or finish name: coarse, standard (No. 4), fine, or non-directional satin
• Grain direction, and the datum it is measured from
• Whether brushing happens before or after forming, and how the bend is to be treated
• Faces that are cosmetic and faces that are not — finishing effort belongs where it shows
• Areas that must stay conductive or be masked, if the part is also coated or bonded
• Your appearance acceptance standard, if your incoming inspection grades finish

Lead time and what we need to quote

• Simple samples: 3–7 days. Complex first article: 15–20 days. Production batch: 25–35 days.
• Brushing is part of the finishing route quoted with the part, not a separate line item added afterwards.
• Tooling, where brushing follows a formed part, is quoted separately: 7–15 days simple, 30–45 days complex.

Send 2D drawings (PDF, DWG or DXF) and 3D models (STEP, IGES or SolidWorks) with material, grit or finish name, grain direction and quantity. We will confirm the finish we can hold and quote it with the parts.

Brushing is one of four finishes we work with on stainless and five on aluminum. If you are still deciding which one, the stainless and aluminum enclosure finishes page works through it by what will kill the enclosure rather than by appearance.

Related reading: stainless steel sheet metal fabrication · metal surface finishing · surface treatment for stainless steel · anodized aluminum enclosures