Bead Blasting: Thickness, Specs & Materials

What is Bead blast?

It hides machining marks on aluminum and evens the appearance of metal and polymer additive parts.

How it works

Compressed air accelerates glass or ceramic beads toward the workpiece. Repeated shallow impacts peen and visually homogenize the surface without intentionally cutting it like angular grit. Glass bead in the 80–120 mesh range is common for cosmetic aluminum. Pressure, stand-off, angle, dwell, bead size, and prior roughness control the result; ASME B46.1 or ISO 21920 measurement is needed when Ra is a drawing requirement.

Why specify it

Hides light tool marks on aluminum
Produces a repeatable satin appearance
Removes essentially no bulk material in a controlled cosmetic pass
Prepares a uniform surface before anodizing

Where it falls short

Does not remove deep scratches or pits
Can round sharp edges and soften laser marks
May embed media in soft metals if media and pressure are wrong
Raises rather than lowers some initially smooth surfaces

Bead blast at a glance

Bead blast is a middle-of-the-range finish; its best score is cosmetic quality (65 of 100), at a budget cost. It adds little corrosion protection or lubricity. Surface hardness is not rated: the finish leaves the part's own surface.

Corrosion protectionMinimal5 / 100

Surface hardnessNot rated—

Cosmetic qualityGood65 / 100

LubricityMinimal10 / 100

Relative costBudget15 / 100

Each score is 0–100 against every finish in this catalog. Corrosion comes from salt-spray life (ASTM B117, log scale) and hardness from the finish layer's Vickers or pencil hardness; cosmetic, lubricity and cost are FabDigit's engineering assessment. Economy on the radar is the inverse of cost.

Bead blast key numbers

Typical values from the governing specifications and shop practice; bars are this finish against the highest value among mechanical finishing finishes.

Thickness0 µm0 mil

Thickness: No coating; resulting Ra is typically 1.6–6.3 µm (63–250 µin).
Electrical: Unchanged
Appearance: Uniform satin to matte with fine diffuse texture.

Specifications for Bead blast

The documents a drawing cites to define this finish, with the Type / Class rows that apply. Each links to a page explaining the standard.

Drawing call-out

BEAD BLAST ALL OVER, 120 MESH GLASS BEAD, Ra 1.6 µm MAX, MASK DATUM A AND ALL THREADED HOLES

Which materials take Bead blast?

Verdict per material family, with the grades that behave differently. Each family links to its datasheets in the material library.

Material family	Verdict	Notes
Aluminum	Yes	Commonly used to hide machining marks and prepare a satin anodized appearance. Thin walls and sharp edges need reduced pressure
Brass	Yes	Suitable; protect against smear and media embedment.
Copper Alloy	Yes	Suitable; expect faster cutting and easier smearing than steel.
DMLS / SLM	Yes	Common to remove sintered powder and even metal AM texture.
MJF	Yes	Standard cosmetic clean-up for powder-bed nylon. Do not overblast thin PA12 features
SLS	Yes	Standard cosmetic clean-up for powder-bed nylon.
Stainless Steel	Yes	Produces a uniform satin surface when stainless-dedicated media is used. Avoid carbon-steel-contaminated media
Titanium	Yes	Suitable with contamination-controlled tooling or media.
FDM	With care	Can hide layer lines but also rounds edges and opens porosity.
Magnesium Alloy	With care	Possible with non-sparking media and fire-safe dust control.
Polymer	With care	Light glass bead can frost plastics; aggressive blast erodes edges.
SLA	With care	Light blast can even gloss; heavy blast frosts and can pit resin.
Steel	With care	Produces a satin blast but carbon steel can flash-rust unless coated or oiled promptly.
Zinc Alloy	With care	Soft die-cast zinc cuts quickly and can embed media.

How Bead blast is applied, and what it does to the part

1Degrease
2Mask critical areas
3Blast with 80–120 mesh glass bead
4Clean with filtered air and wash
5Inspect appearance and Ra

Dimensions	Bulk dimensions normally remain unchanged, but repeated impact can round exposed edges and alter precision sealing or optical surfaces.
Build-up per side	0 µm — No intentional buildup or measurable bulk removal; edge rounding is possible.
Masking	Usually needed. Mask sealing faces, bearing fits, threads, datums, labels, and surfaces whose roughness must remain unchanged.
Electrical	Unchanged
Appearance	Uniform satin to matte with fine diffuse texture.
Added lead time	1–3 working days on top of the bare part

Design rules for Bead blast

What to decide on the drawing before the part goes to the finisher.

State bead material and mesh.Glass bead 80–120 mesh gives a different texture from ceramic bead.
Specify Ra separately from appearance.Visual uniformity does not guarantee profilometer roughness.
Mask functional datums and fits.Impact can change texture and edge condition.
Approve a limit sample for cosmetic work.Pressure, dwell, and alloy change gloss.

Bead blast versus the alternatives

Finishes engineers weigh against Bead blast, and when each wins.

Finish	Corrosion	Hardness	Cosmetic	Cost	Choose it when
Bead blast this page	5	—	65	$	—
Sand Blasting Bead blast vs Sand Blasting →	0	—	35	$	when aggressive scale removal or coating key is required
Wet Blasting Bead blast vs Wet Blasting →	5	—	70	$$	when a finer slurry-blasted satin surface is preferred

Bead blastSand Blasting

The radar overlays Bead blast with Sand Blasting, its most common alternative — chosen when aggressive scale removal or coating key is required. Scores in the table are 0–100 across every finish in the catalog.

Cost, lead time and compliance

Relative cost

Bead Blasting is a budget-cost finish ($): cheaper than about 85 % of the finishes FabDigit quotes.

Finishing is priced per part with a lot minimum, from FabDigit's own China-side rates cross-checked against US job-shop pricing. The exact figure appears on the instant quote once the part is uploaded.

Lead time and compliance

Added lead time	1–3 working days
RoHS	Compliant
Notes	The process adds no regulated coating; collect spent media and removed contaminants.

What Bead blast is used for

Aluminum electronics housings
Stainless instrument panels
MJF and SLS cosmetic parts
Pre-anodize cosmetic preparation

Bead blast — frequently asked

bead blast vs sand blast

Bead blasting uses spherical media and usually gives Ra 1.6–6.3 µm (63–250 µin) with a softer satin look. Sand blasting normally uses angular grit, cuts more aggressively, and commonly leaves Ra 3.2–12.5 µm (125–500 µin).

does bead blasting change dimensions

A controlled cosmetic pass removes essentially no bulk material. It can still round sharp edges, soften markings, and disturb precision sealing surfaces, so mask critical features.

what glass bead size is used for aluminum

Glass bead in the 80–120 mesh range is common for cosmetic aluminum. The drawing should state media, mesh, Ra limit, and masked surfaces.

does bead blasting hide machining marks

It hides shallow tool marks by making reflectance uniform, especially on aluminum. Deep cutter tracks remain visible and must be sanded or polished first.

how is bead blasted roughness measured

Measure Ra with a suitable cutoff and evaluation length under ASME B46.1 or ISO 21920. Do not accept a visual sample as a substitute when Ra is functional.