Sandblasting aluminum uses compressed air to propel abrasive particles that either cut the surface (raising adhesion for coatings) or peen it (creating an even satin look). What you get—strong coating adhesion, premium matte, or fast paint stripping—depends on five knobs you control: media type, grit size, pressure (PSI), standoff distance, and travel speed.
Most people assume “sand” is the default for blasting, but aluminum needs purpose-made blasting media and controlled settings. The safest way to learn is to standardize a small routine: clean → mask → test coupon → full part → coat or anodize within 4–24 hours. Do that, and you’ll avoid warping thin sections, over-texturing faces, or contaminating your aluminum with the wrong abrasive.
What sandblasting does to aluminum
When abrasive particles hit aluminum, they either cut (sharp edges slice micro-grooves) or peen (rounded particles compress peaks and valleys). Cutting media—like aluminum oxide, crushed glass, or garnet—build a sharper “anchor profile” that helps primers and powders grab. Peening media—especially glass bead—produce a uniform, premium satin matte with typically lower Ra, which is great for visible housings.
Aluminum is softer and conducts heat faster than steel, so it’s easier to over-cut or “heat soak.” Keep the PSI moderate, hold a steady standoff (roughly 150–250 mm), work at a 60–80° angle, and never dwell at edges or on thin ribs. These simple habits prevent most defects.
Aluminum blasting cheat sheet
| Goal | Recommended Media | Typical Grit | Start PSI | Standoff / Angle | Expected Surface / Ra | Common Uses | Avoid |
|---|---|---|---|---|---|---|---|
| Decorative matte (satin) | Glass bead | 80–120 | 30–60 | 150–250 mm / 60–80° | Even satin, Ra ≈ 0.6–1.2 μm | Visible housings, lighting parts | Don’t dwell at edges |
| Strong adhesion for coatings | Aluminum oxide (brown/white) | 100–150 | 40–80 | 150–250 mm / 60–80° | Sharper micro-profile for primer/powder/anodize | Primer, powder, paint, anodize prep | No steel shot/grit; no silica sand |
| Fast stripping | Crushed glass / Garnet | 60–100 | 60–80 | 150–250 mm / 70–90° | Quick removal, moderate profile | Old paint, heavy oxide | Refine if low Ra is required |
| Delicate / mixed materials | Soda / Walnut / Plastic | 60–120 | 20–40 | 150–250 mm / 60–80° | Very gentle, low profile | Gaskets, plastics near Al | Not ideal for high adhesion |
| Wheels & rims | Crushed glass → Bead (finish) | 60–80 → 80–120 | 60–80 → 40–60 | 150–250 mm / 60–80° | Uniform matte ready to coat | Automotive aluminum wheels | Must mask bores/seats |
Is it safe to sandblast aluminum?
Yes—if you avoid the two classic mistakes: too much pressure and the wrong media. For cosmetic faces, most shops start around 30–60 PSI with glass bead; for coating prep, 40–80 PSI with aluminum oxide is a dependable band. Always mask threads, bearing seats, and sealing bores. Never use silica sand (serious health risk and poor finish control) and avoid steel shot/grit (iron can embed in aluminum and trigger galvanic corrosion and coating failures). If a part is thin or highly ribbed, go gentler: increase standoff, reduce PSI, and keep the nozzle moving.
How to choosing blasting media for aluminum
Aluminum oxide (AO).
The most common production choice for coating adhesion. Start with 100–150 grit. Brown AO is durable and cost-effective for large batches. White AO is cleaner and slightly sharper, popular before anodizing to keep the profile clean. Black AO (slag-based) strips fast and is economical but needs dust and breakdown control. Coarser sizes (60–80) remove paint quickly but leave a rougher texture; finer (180–220) clean gently with a lower profile.
Glass bead (bead blasting aluminum finish).
Bead peens instead of cutting, giving a uniform satin look with lower Ra—perfect for visible aluminum parts like lighting housings. A reliable starting point is bead 80–120 at 30–60 PSI. If a powder spec demands more tooth, follow bead with a very light AO 120–150 pass to raise micro-profile without losing the satin.
Crushed glass or garnet.
Choose these when throughput matters—stripping heavy paint or oxidation fast. After the quick cut, refine with AO 120–150 if your coating requires a tighter Ra band.
Soda, walnut shell, and plastic media.
These are gentle—great for mixed materials or delicate assemblies where cutting is risky—but they rarely create enough tooth for durable coatings. If adhesion matters, follow with a light AO pass.
Media comparison for aluminum
| Media | Hardness (approx.) | Cut/Peen Behavior | Typical Ra Band on Al | Recyclability | Best For | Avoid / Notes |
|---|---|---|---|---|---|---|
| Aluminum Oxide (Brown) | Mohs ~9 | Cutting | 1.0–2.5 μm (100–150 grit) | High | Robust adhesion before primer/powder | Can over-texture if too coarse; manage dust |
| Aluminum Oxide (White) | Mohs ~9 | Cutting (cleaner) | 1.0–2.0 μm | High | Clean profile before anodize | Keep air dry/clean; slightly higher media cost |
| Black AO / Slag-based | ~8–9 (var.) | Cutting (aggressive) | 1.2–2.8 μm | Medium | Fast stripping at low cost | Grade consistency varies; control dust |
| Glass Bead | Mohs ~6 | Peening (satin) | 0.6–1.2 μm | Medium | Decorative matte, visible housings | Lower tooth—add light AO if needed |
| Crushed Glass | ~6 | Cutting (fast) | 1.0–2.0 μm | Medium | Quick paint/oxide removal | Refine for smoother coatings |
| Garnet | ~7–7.5 | Cutting (stable) | 1.0–2.0 μm | Medium–High | Consistent stripping, decent recycle | Good shop hygiene; tune grading |
| Soda | ~2.5 | Gentle cleaning | <0.8 μm | Low | Residue-sensitive cleaning | Minimal tooth—follow with AO for adhesion |
| Walnut / Plastic | ~3–4 | Gentle | <0.8 μm | Low | Very delicate surfaces | Not for high-adhesion prep |
| Silica Sand | ~6–7 | Inconsistent | — | — | — | Do not use (health & quality) |
| Steel Shot/Grit | — | Peen/Cut | — | High | Steel only | Do not use on aluminum (Fe embedment) |
Ra bands are indicative; confirm on test coupons. Equipment, flow rate, nozzle, and traverse speed all influence results.
How to setting sandblast aluminum
A practical way to pick parameters is to work backward from the result you want and use the table below as a starting map. Always validate on a test coupon, then record the final recipe (media × grit × PSI × standoff × travel speed) so the line can repeat it lot after lot.
Presets by target finish
| Target Finish / Task | Start Grit | Start PSI | Standoff / Angle | Notes (tuning & QA) |
|---|---|---|---|---|
| Satin decorative matte (bead blast aluminium) | Bead 80–120 | 30–60 | 150–250 mm / 60–80° | 30–50% overlap; even travel; gloves-only handling |
| Primer/Powder prep (sandblasting with aluminum oxide) | AO 100–150 | 40–80 | 150–250 mm / 60–80° | Verify adhesion on coupon; match powder spec |
| Anodize prep | White AO 120–150 | 45–65 | 150–250 mm / 60–80° | Clean profile; hand off to anodize ≤24 h |
| Fast stripping | Crushed glass 60–80 or Garnet 60–80 | 60–80 | 150–250 mm / 70–90° | Add AO 120–150 pass if low Ra is required |
| Thin covers / ribs | Bead 100–170 | 25–40 | 180–250 mm / 60–70° | Increase standoff & speed; confirm on coupon |
| Wheels (refinish flow) | CG 60–80 → Bead 80–120 | 60–80 → 40–60 | 150–250 mm / 60–80° | Mask bores/seats; keep lance moving on spokes |
Bead blasting aluminum finishes
Bead blasting excels when you need visually consistent satin across large faces—no streaks, no glare, softer highlights. That’s why it’s common on lighting housings and other visible die-cast parts. If adhesion is the top priority, AO wins; if the look is king, bead wins. Many teams combine both: bead first for uniformity, then a quick low-pressure AO 120–150 touch to lift the micro-profile without killing the satin. Always confirm Ra/Rz and coating adhesion on coupons before you scale.
Sandblasting aluminum wheels
Wheels can be blasted safely with proper masking and heat control. A dependable flow is: clean and inspect, strip with crushed glass 60–80 at 60–80 PSI, then finish with bead 80–120 at 40–60 PSI for a uniform matte (or AO 120–150 if maximum adhesion matters). Degrease thoroughly and coat promptly—often epoxy/zinc primer under powder or clear. Keep the nozzle moving, especially on thin spokes, and check the finish for evenness before coating.
Quick wheel tips (scan-friendly add-on):
- Mask bores, bearing seats, valve areas, and threads before blasting.
- Keep the wheel rotating or the nozzle moving—don’t dwell on spokes.
- Strip fast, finish smooth, and coat within 4–24 h.
- Verify no peening glare and confirm adhesion after cure.
“Sandblasting sand” and safety
Retail “sand” queries are common, but silica sand is a poor choice: it poses serious health risks (respirable free silica) and its grading/shape are inconsistent for aluminum finishes. Use engineered media—aluminum oxide, glass bead, crushed glass, or garnet—with proper dust collection, PPE, and grounding. You’ll get safer, cleaner, more repeatable results.
After blasting: timing for primer, powder, or anodize
Blasting exposes fresh metal and raises surface energy. Don’t let that preparation go stale. Prime, powder, or anodize within 4–24 hours; sooner is better. If you must hold parts, bag them dry with desiccant and handle with gloves. Before coating, confirm the surface is free of fingerprints and dust; keep rinse steps clean if you’re heading into anodize.
Production controls buyers actually care about
Serious buyers expect repeatability. Lock your media × grit × PSI × standoff × path speed on a test coupon per alloy and geometry. Track nozzle wear hours, air pressure and dryness, and media recycle cycles. Verify Ra/Rz where required and maintain a visual swatch board so operators can match look and feel. For critical parts, provide a simple record: media lot, settings, first-piece approval, and finish inspection notes.
From blasting to aluminum die casting
Lighting-grade die-cast aluminum housings, ready to coat. We run 800–2000-ton aluminum die-casting cells with in-line de-burr → blast (bead/AO) → powder or anodize. For A380/ADC12/AlSi10Mg parts we deliver a defined Ra, a clear media × grit × PSI recipe, and inspection data—so every lot looks the same and coatings stick.
→ Get Ra Spec & Sample in 48h • → Upload Drawing for DFM + Finish Plan
Sandblast Aluminum FAQ
1) 100 vs 120 vs 220 grit aluminum oxide on aluminum—what really changes?
100 cuts faster and leaves a higher anchor profile for tough primers/powders; 120 balances cut and cosmetics; 220 is gentler for light cleaning or anodize pre-polish. Many production lines start at 120–150 and tune by coupon.
2) Is 70-grit AO too aggressive for thin or cosmetic aluminum?
Usually yes. It’s fine for heavy stripping on robust parts, but thin covers and visible faces do better with 100–120 at moderate PSI.
3) Is black AO 80-grit good for wheel stripping?
It removes coatings quickly. For a smooth refinish, follow with AO 120–150 or bead 80–120 to control roughness before coating.
4) What’s the best blasting media for aluminum wheels?
For a uniform matte, glass bead 80–120 at moderate PSI. For maximum adhesion or harsh service, AO 120–150. Many shops strip with crushed glass, then finish with bead.
5) Bead blasting vs “sandblasting” aluminum—how should I decide?
Treat AO/crushed glass as cutting (higher profile) and bead as peening (smoother satin). Choose bead for premium look, AO for adhesion, or bead-then-AO for a balanced hybrid.
6) Is soda blasting okay for aluminum engine parts?
Yes for gentle cleaning, but it leaves little tooth. If paint or powder must grip hard, finish with a light AO pass.
7) Can I use store-bought “sandblasting sand” or beach sand on aluminum?
Avoid it. Use engineered media and proper dust extraction and PPE. You’ll get safer, cleaner, and more consistent results.
8) “Best grit for sandblasting rust” vs aluminum—why isn’t it the same?
“Rust” searches target steel. Aluminum forms oxide, not red rust, and it dislikes steel media. For aluminum, stick with AO 100–150 or bead 80–120.
9) What actually drives the cost of blasting aluminum parts?
Media recycle life, nozzle wear, air/energy load, masking and cleanup labor, and any Ra/adhesion metrology. Tight Ra windows and complex masking raise cost and lead time.
10) PSI settings for aluminum blasting—any rule of thumb if I’m new?
Start at 30–60 PSI for bead and 40–80 PSI for AO with a 150–250 mm standoff. Tune the finish with travel speed and angle before increasing pressure.
