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Sand Blasting

Mechanical finishing · Mechanical

Sand blasting uses angular abrasive to remove scale, rust, and coatings or to create a rough coating-ready surface.

CNC machiningSheet metalCastingBudget cost $Unchanged
Quote a part with Sand blastCompare mechanical finishing
Sand Blasting on a machined part

What is Sand blast?

Modern shops normally use alumina, garnet, or other controlled grit rather than free silica sand.

How it works

Air or wheel blasting drives angular abrasive into the substrate, cutting peaks and removing contamination. Alumina from 60–220 grit covers aggressive cleaning through finer preparation; 60–120 grit is common for coating key. Blast cleanliness may be specified under ISO 8501-1 or an SSPC-SP visual preparation grade, while final roughness is measured under ASME B46.1 or ISO 21920. Profile and cleanliness require separate acceptance criteria.

Why specify it

  • Removes rust, scale, and old coating
  • Creates mechanical key for paint or powder coat
  • Reaches complex external geometry
  • Produces Ra about 3.2–12.5 µm (125–500 µin) in common job-shop work

Where it falls short

  • Can warp thin sheet
  • Rounds edges and erodes small features
  • May embed abrasive or contaminate stainless
  • Free silica sand presents a serious inhalation hazard

Sand blast at a glance

Sand blast is a middle-of-the-range finish; its best score is cosmetic quality (35 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 protectionMinimal0 / 100
Surface hardnessNot rated—
Cosmetic qualityFair35 / 100
LubricityMinimal5 / 100
Relative costBudget15 / 100
CorrosionHardnessCosmeticLubricityEconomy

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.

Sand 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; typical resulting Ra 3.2–12.5 µm (125–500 µin).
Electrical
Unchanged
Appearance
Rough, non-directional matte surface.

Specifications for Sand 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

ABRASIVE BLAST EXTERNAL SURFACES WITH 120 GRIT ALUMINUM OXIDE TO Ra 6.3–10 µm, ISO 8501-1 Sa 2½, MASK THREADS AND DATUMS

Which materials take Sand blast?

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

Material familyVerdictNotes
Brass
YesSuitable; protect against smear and media embedment.
Copper Alloy
YesSuitable; expect faster cutting and easier smearing than steel.
Steel
YesStandard preparation for scale removal and coating key.
Aluminum
With careSoft substrate erodes quickly and thin sections can distort.
Magnesium Alloy
With carePossible with non-sparking media and fire-safe dust control.
Stainless Steel
With careUse dedicated clean media to prevent free-iron contamination.
Titanium
With careUse iron-free alumina or garnet; silica sand is the wrong media and a health hazard.
Zinc Alloy
With careSoft die-cast zinc cuts quickly and can embed media.
Polymer
LimitedAngular grit rapidly erodes plastics; use only for controlled texture trials.

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

  1. 1Degrease
  2. 2Mask critical areas
  3. 3Blast with specified 60–220 grit abrasive
  4. 4Remove residual abrasive
  5. 5Verify cleanliness profile and Ra
DimensionsMaterial is removed and edges are rounded; removal is process-dependent and must not be assumed zero on close-tolerance features.
Build-up per side0 µm — No buildup; measurable cutting depends on grit, pressure, dwell, and substrate.
MaskingUsually needed. Mask threads, fits, sealing faces, labels, and thin or fragile features.
ElectricalUnchanged
AppearanceRough, non-directional matte surface.
Added lead time1–3 working days on top of the bare part

Design rules for Sand blast

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

  1. Specify abrasive type and grit.Alumina 60 grit cuts far more aggressively than 220 grit.
  2. State the cleanliness grade.ISO 8501 and SSPC-SP grades describe contamination removal, not Ra.
  3. Protect thin sheet.Peening stress and heat can distort panels.
  4. Use dedicated media for stainless.Carbon-steel contamination can create rust spots.

Sand blast versus the alternatives

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

FinishCorrosionHardnessCosmeticCostThicknessChoose it when
Sand blast
this page
0—35$0 µm—
Bead Blasting
Sand blast vs Bead Blasting →
5—65$0 µmwhen a gentler cosmetic satin finish is required
Wet Blasting
Sand blast vs Wet Blasting →
5—70$$0 µmwhen dust and dry-media embedment must be reduced
CorrosionHardnessCosmeticLubricityEconomy
Sand blastBead Blasting

The radar overlays Sand blast with Bead Blasting, its most common alternative — chosen when a gentler cosmetic satin finish is required. Scores in the table are 0–100 across every finish in the catalog.

Cost, lead time and compliance

Relative cost

Sand 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 time1–3 working days
RoHSCompliant
NotesUse contained blasting and dust collection; avoid free crystalline silica abrasive.

What Sand blast is used for

  • Steel weldments before coating
  • Castings before paint
  • Rust removal
  • Slip-resistant industrial surfaces

Sand blast — frequently asked

bead blast vs sand blast

Sand blasting uses angular cutting grit and commonly leaves Ra 3.2–12.5 µm (125–500 µin). Glass bead is spherical, gentler, and commonly leaves Ra 1.6–6.3 µm (63–250 µin).

what grit is used for sand blasting

Aluminum oxide from 60–220 grit is common. Coarse 60–120 grit cleans and profiles aggressively; finer 180–220 grit makes a less coarse texture.

what is Sa 2.5 blast cleaning

ISO 8501-1 Sa 2½ is very thorough blast cleaning with only slight traces of contamination remaining. It is a cleanliness grade, not a roughness value.

does sand blasting remove material

Yes. Removal varies with abrasive, pressure, angle, dwell, and hardness, so close-tolerance surfaces must be masked or machined afterward.

can stainless steel be sand blasted

Yes, with clean stainless-dedicated media and equipment. Carbon-steel carryover can create free-iron contamination and later rust staining.