Bead blasted matte finish

Bead Blasted Aluminum Finish

Bead blasting is the great equalizer of machined surfaces: a controlled stream of glass media that replaces tool marks, blend lines, and handling scratches with one uniform satin-matte texture.

On its own it's a cosmetic finish; before anodizing it's the difference between a part that looks machined and a part that looks manufactured.

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What this finish is

Controlled texture, not just cleaning

Bead blasting propels spherical glass media against the aluminum surface, peening it into a non-directional matte. Unlike sandblasting's angular grit, glass bead rounds the surface profile rather than tearing it — the result is smooth to the touch, low-glare, and visually uniform across faces machined by different tools at different times.

The variables that define the result are media size, air pressure, and coverage. We specify all three per part family so that this month's batch matches last month's — 'bead blast' without parameters is a different finish from every supplier.

Texture
Non-directional satin matte; typical media #80–#220 glass bead, finer media = silkier surface.
Dimensional impact
Negligible on general tolerances; masked on fits tighter than ±0.02 mm and on sealing lands.
Surface roughness
Slightly raises Ra versus fine machining — don't blast Ra 0.8 functional faces.
Usually a preparation step
Most blasted parts continue to clear or black anodize; blasting sets the texture, anodize sets the protection.
Appearance lifetime
Bare blasted aluminum fingerprints easily — anodize over it for surfaces that get touched.

Benefits

What bead blasting buys you

One inexpensive step solves most cosmetic complaints machined parts generate.

Erases tool witness lines

Pocketing passes, blend boundaries, and re-fixturing marks disappear into one uniform field.

Batch-to-batch consistency

With media and pressure specified, blasted parts from different machines and months match on the same shelf.

The anodizing equalizer

Anodize amplifies whatever texture it grows on — blasting first is why production anodized parts look uniform.

Hides service wear

Matte texture disguises the small scratches and rub marks that show immediately on bright machined faces.

Glare control

Diffuse reflection instead of mirror glints — relevant around vision systems, optics, and operator stations.

Improved grip feel

Hand-loaded tooling and handled covers get a tactile, non-slippery surface.

Typical applications

Where bead blasted parts show up

Anywhere the part is seen or touched — usually as the texture step under an anodized finish.

Consumer product enclosures

The blast-then-anodize recipe behind most premium aluminum electronics housings.

Instrument and device panels

Front panels and bezels with uniform matte that hides fingerprints in daily use.

Robotics and machine covers

Customer-visible cell hardware where mixed machining marks would look unfinished.

Medical equipment surfaces

Satin texture under sealed anodize — the standard cleanable cosmetic in clinical settings.

Optics-adjacent hardware

Blasted and black-anodized surfaces controlling stray reflections around cameras and lasers.

Hand-loaded tooling

Operator-facing fixtures where grip and wear-hiding both help.

Design considerations

Designing for bead blasting

Blasting is forgiving, but a few callouts keep it from touching the surfaces that can't afford it.

Specify the media grit

Call out media size (e.g., #120 glass bead) on the drawing. Coarser reads industrial, finer reads consumer — and unspecified reads different every order.

Mask fits and sealing surfaces

Blasting peens edges and raises Ra. H7 bores, O-ring grooves, and Ra-controlled faces get masked — list them explicitly.

Don't blast threads

Media lodges in threads and alters fit. Threads are masked or plugged by default; confirm the callout so gauging stays valid.

Mind sharp cosmetic edges

Blasting slightly rounds crisp chamfer lines. If a knife-edge aesthetic matters, tell us — we adjust pressure and standoff.

Blast before anodize, always

Sequence is blast → etch → anodize. Blasting an anodized part destroys the film — plan the finish stack, not individual steps.

Define the cosmetic zone

Full-body blasting costs more than show-face blasting. Marking which faces are cosmetic keeps the price matched to the requirement.

Compatible aluminum grades

Alloy behavior under glass bead

Every machinable alloy blasts well — the differences show in the follow-on anodize tone.

Alloy	Suitability	Engineering notes
6061-T6	Excellent	The reference combination — uniform matte, then bright uniform anodize
7075-T6	Excellent	Blasts uniformly; expect the alloy's darker tone after anodizing
5052-H32	Good	Softer surface picks up handling marks after blasting — finish late, pack carefully
2024-T351	Good	Blast texture helps hide 2024's uneven anodize film tone
MIC-6	Fair	Works, but cast porosity can read as speckle — rarely worth it on tooling

Comparing coatings instead? Return to the aluminum surface finishes hub or read the full anodized aluminum CNC machining guide.

Quote your bead blasted parts

Upload CAD with cosmetic faces, grit preference, and masked features marked — or send a reference photo of the texture you want and we'll translate it into parameters. Review within one business day.