Most people assume “sand” is the default for blasting, but aluminum needs purpose-made blasting media and controlled settings. In simple terms, 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).
The result—strong coating adhesion, premium matte, or fast paint removal—depends on five knobs you control: media type, grit size, pressure (PSI), standoff distance, and travel speed.
A safe routine to standardize is: clean → mask → test coupon → full part → coat or anodize within 4–24 hours. This avoids warping thin sections, over-texturing faces, or contaminating your aluminum with the wrong abrasive.
What Blasting Actually Does to Aluminum (Cut vs Peen)
When abrasive particles hit aluminum, they either cut (sharp particles slice micro-grooves, building a higher “anchor profile”) or peen (rounded particles compress peaks/valleys and even out reflections). Cutting media—like aluminum oxide (AO), crushed glass, or garnet—build a sharper profile for primers and powders.
Peening media—especially glass bead—produce a uniform, premium satin matte with typically lower Ra, great for visible housings.
Aluminum is softer and conducts heat faster than steel, so it’s easier to over-cut or “heat soak.” Keep PSI moderate, hold a steady standoff (about 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—ideal 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 choose settings without guessing: Grit and PSI
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: Workflow & Wheel Tips Step-by-Step
Aluminum wheels can be blasted safely and consistently if you separate stripping from finishing, control heat input, and protect precision fits. The objective is a uniform, matte surface with the anchor profile your coating needs—without peening glare, over-cut edges, or dimensional risk.
Pre-check & masking
Remove weights, valves, seals, and TPMS sensors. Degrease thoroughly. Mask bearing bores, hub seats, threads, and valve areas so media cannot touch functional fits.
Strip (remove old coatings fast)
Use crushed glass or garnet 60–80 grit at 60–80 PSI. Keep the nozzle 150–250 mm away at a 70–90° angle for efficient removal. Do not dwell on thin spokes; keep a steady traverse.
Finish (set the final look and profile)
For a premium, even satin: glass bead 80–120 at 40–60 PSI.
If maximum adhesion is the top priority (harsh service, aggressive topcoats): aluminum oxide 120–150 at 45–70 PSI.
Maintain consistent overlap (about 30–50%) and avoid edge dwell to prevent glare or over-cut.
Clean & inspect
Blow down, dry wipe, and visually confirm no residual media in bores or behind spokes. Look for uniform sheen—no patchiness, no streaks, no bright peening spots.
Coat promptly
Apply epoxy/zinc primer where specified, then powder or clear. Aim to prime/powder within 4–24 hours of blasting. Handle with gloves only.
Final QC
Confirm even appearance, check masked areas and fits, and verify coating adhesion after cure.
Wheel Parameter Presets
| Stage | Media | Grit | Start PSI | Notes |
|---|---|---|---|---|
| Strip old paint/clear | Crushed glass or Garnet | 60–80 | 60–80 | Throughput first; keep nozzle moving on thin spokes |
| Finish for satin look | Glass bead | 80–120 | 40–60 | Uniform matte; lower Ra; minimize glare with even overlap |
| Finish for higher adhesion | Aluminum oxide | 120–150 | 45–70 | Sharper micro-profile; ideal before robust primers/powders |
Adjust by standoff (150–250 mm), angle (60–80°), and traverse speed rather than simply raising PSI. Always prove settings on a test wheel or coupon.
Wheel Tips: Quick Reference (PSI, Masking, Timing)
- Mask with intent. Plug threads and cap bores to protect functional geometry and stop media entrapment.
- Keep it moving. Never dwell on spokes or edges—heat and over-cut happen fast on aluminum.
- Two-step is safer. Strip fast (crushed glass/garnet), then finish (bead for look, AO for tooth).
- Check uniformity wet and dry. A quick solvent wipe can reveal hidden streaks or glare before coating.
- Coat within the window. Prime/powder within 4–24 hours; sooner is better.
- Gloves only. Fingerprints can telegraph through clear coats and powders.
Common Mistakes & How to Fix Them
- Peening glare (shiny patches) → Lower PSI, increase standoff, even out overlap; switch to finer bead or finish with a light AO 120–150 touch.
- Over-cut edges or thin spokes → Reduce PSI, widen pattern, increase travel speed; reserve aggressive media for stripping only.
- Patchy matte → Stabilize media flow, ensure dry air, standardize 30–50% overlap; re-finish with controlled passes.
- Media trapped in bores/valve holes → Improve masking, blow down from multiple angles, inspect before coating.
- Poor coating adhesion → If bead-only finish struggled, add a light AO 120–150 pass to raise anchor profile, then re-prime and cure per spec.
Quality Checks Before Coating
- Uniform sheen under consistent lighting (no bright spots, no streaks).
- Clean masked areas; remove all media from bores and cavities.
- If specified, record media × grit × PSI × standoff × speed and keep a photo of the finish standard for repeatability.
- Proceed to primer/powder promptly; if delayed, bag dry with desiccant and re-wipe before coating.
“Sandblasting sand” and safety (why not plain sand)
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
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 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.
