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Bead blasted
Bead blasting propels fine glass beads at a part with compressed air to produce a uniform satin-matte surface. It softens light tool marks, fingerprints and machining lines and is the usual prep before a cosmetic anodize. Typical results are 32–125 µin Ra (0.8–3.2 µm) depending on media and pressure. Dimensional change is minimal, but sharp edges round slightly.
- Applies to
- Aluminum, stainless steel, titanium, steel, zinc and aluminum die castings, and 3D-printed metal and nylon parts
- Adds
- 2 days
- Cost
- Low
Specs
| Typical media | Glass bead, about 70–170 mesh (90–210 µm) |
|---|---|
| Blast pressure | 40–80 psi (2.8–5.5 bar) typical |
| Resulting roughness | 32–125 µin Ra (0.8–3.2 µm), media dependent |
| Dimensional change | Negligible on most features; sharp edges round slightly |
| Masking | Threads, bores, sealing and datum faces as specified |
| Appearance | Uniform satin to matte, low glare |
Call out on the drawing
- MIL-PRF-9954 (glass bead media)
- SAE AMS 2431 (peening media, when bead peening is required)
- SSPC-SP 10 / NACE No. 2 (near-white blast, steel coating prep)
Materials it suits
Structural aluminum6061-T6
Extrusion aluminum6063-T5
Aerospace aluminum7075-T6
Marine aluminum5052-H32
Die-cast aluminumA380
Mild steel1018
Carbon steel1045
Alloy steel4140
Structural steelA36
Machining stainless303 SS
Everyday stainless304 SS
Marine stainless316 SS
Magnetic stainless430 SS
Hardened stainless17-4 PH
Machining brassC360 brass
TitaniumTi-6Al-4V
3D-print nylonPA12
Questions
Should I bead blast before anodizing?
Yes, for cosmetic parts. Blasting evens out tool marks and gives a consistent matte base, so black or colored anodize looks uniform. Specify the media, for example glass bead, and the anodize type on the drawing.
Does bead blasting change part dimensions?
Only slightly. Glass bead removes almost no material but rounds sharp edges and can affect very small features and fine threads. Mask bores, threads and sealing faces that must stay as machined.
Bead blasting vs sandblasting?
Bead blasting uses round glass beads that peen the surface to a satin finish with little material removal. Sand, aluminum oxide or steel grit cuts the surface to a rougher anchor profile, which suits paint and powder coat adhesion on steel.
Does bead blasting hide machining marks?
It softens light tool paths and blends small mismatches, but deep marks and step lines still show. For show surfaces, call out a finer machined finish plus blasting.
Price it with this finish.
The builder adds lot charges, per-part cost and lead time for the finish you pick.