Sandblasting Use: 88 Mesh vs. 120 Mesh SiC: Which for Rust Removal? When to Pick High Purity?
In industrial surface preparation, sandblasting with silicon carbide (SiC) is a fast, effective way to remove rust, scale, old coatings, and surface contaminants from metals and other materials. However, not all SiC grits perform the same - the choice between 88 mesh and 120 mesh, as well as the purity level, significantly affects cutting efficiency, surface profile, and reuse potential.
At ZhenAn, with 30 years of experience supplying SiC for abrasive blasting applications worldwide, we help contractors and manufacturers select the right mesh size and purity for their rust removal jobs.
1. How SiC Works in Sandblasting Rust Removal
Sandblasting removes rust by micro-cutting and fracturing the oxide layer and surface metal. SiC's extreme hardness (Mohs ~9.5) and sharp fracture pattern constantly expose fresh cutting edges, allowing:
Fast material removal
Controlled surface profile (anchor pattern for coatings)
Minimal embedment in softer base metals compared to some other abrasives
Two main factors determine performance in rust removal: mesh size (grit coarseness) and purity (impurity-related wear & contamination).
2. 88 Mesh vs. 120 Mesh SiC: Cutting Characteristics
Mesh size indicates the number of openings per inch in a screening sieve - smaller mesh number = larger particle.
|
Mesh |
Approx. Particle Size |
Profile Created |
Cutting Speed |
Typical Use |
|---|---|---|---|---|
|
88 mesh |
~180 µm |
Deeper anchor pattern, rougher finish |
Faster rust/scale removal |
Heavy rust, thick scale, large surfaces |
|
120 mesh |
~125 µm |
Finer anchor pattern, smoother finish |
Slower but more controlled removal |
Light rust, pre-paint finishing, delicate areas |
88 mesh:
Pros: Aggressive removal, fewer passes for thick rust or heavy mill scale.
Cons: Leaves deeper profile; may be too aggressive on thin sheet metal or machined surfaces.
120 mesh:
Pros: More controlled, less risk of damaging base metal; better when a finer surface is needed for coating adhesion.
Cons: Slower removal rate on heavy rust.
3. Matching Mesh to Substrate & Rust Severity
Heavy Rust / Thick Mill Scale (e.g., structural steel, bridges): 88 mesh - fast removal, deep profile acceptable for subsequent coating.
Light Rust / Surface Oxide (e.g., machined parts, thin panels): 120 mesh - avoids warping or over-penetration.
Pre-Coating Finish (paint, powder coat): 120 mesh - provides clean, consistent anchor profile without deep peaks.
Mixed Conditions: Start with 88 mesh to strip bulk rust, follow with 120 mesh to refine surface.
4. When to Pick High Purity SiC
Standard SiC 88 (~88% SiC) works well for general rust removal, but high purity SiC (≥98%, green SiC >99%) is preferable when:
Minimal Contamination Needed
Lower-purity SiC contains silica and other compounds that can embed in soft metals or leave residue, affecting coating adhesion or surface inspection (e.g., NDT).
Reuse & Recycling
High-purity SiC fractures more predictably and has less friable impurity phase, so it lasts longer in recycling systems.
Sensitive Base Metals
On stainless steel, aluminum alloys, or precision parts, impurities can cause galvanic corrosion or staining.
Environmental & Safety Compliance
Some high-purity SiC generates less dust with certain binders/coatings, aiding workplace air quality.
For routine structural steel blasting, SiC 88 is cost-effective. For high-value components, aerospace, food-grade stainless, or critical coating applications, upgrade to high-purity.
5. Industry Application Examples
Ship Hulls & Decks: 88 mesh SiC 88 for rapid removal of marine corrosion; profile depth aids anti-fouling paint adhesion.
Automotive Frame Restoration: 120 mesh high-purity SiC to avoid warping thin panels and prevent surface contamination before powder coating.
Pipeline Exterior Surfaces: 88 mesh for heavy scale; 120 mesh for final pass to ensure uniform anchor pattern.
Food Processing Equipment: High-purity 120 mesh to eliminate risk of silica contamination on stainless steel surfaces.
6. Practical Selection Guidelines
Assess Rust Thickness → Choose coarser mesh for heavy rust.
Check Base Metal Thickness & Machining → Use finer mesh to avoid damage.
Determine Required Surface Profile → Match mesh to coating manufacturer specs.
Evaluate Reuse Potential → High-purity for recyclable blast systems.
Consider Contamination Limits → High-purity for sensitive metals or critical applications.
7. Why Choose ZhenAn for Sandblasting SiC
30 years of experience in producing consistent SiC abrasives for blasting
Full range: 88 mesh, 120 mesh, SiC 88, high-purity, green SiC
ISO & SGS certified for reliable quality and performance
Custom packaging for bulk or recycling systems
Global supply ensuring on-time delivery to blasting contractors & manufacturers
Conclusion
For rust removal, 88 mesh SiC offers faster cutting and deeper profiles, ideal for heavy rust and thick scale, while 120 mesh SiC provides controlled removal and finer finish for light rust and delicate surfaces. High purity SiC should be chosen when contamination must be minimized, longer abrasive life is needed, or the base metal is sensitive. Matching mesh size and purity to the job requirements ensures efficient blasting and high-quality surface preparation.
For expert advice on SiC grit selection for your sandblasting projects, contact our team at:
FAQ
Q1: Can I use 88 mesh on thin aluminum panels?
A: Not recommended - it may warp the panel; use 120 mesh or finer.
Q2: Does high-purity SiC really last longer in recycling?
A: Yes, fewer impurities mean more predictable fracture and less breakdown during reuse.
Q3: What surface profile does 120 mesh typically leave?
A: Finer anchor pattern (lower Ra) suitable for paint and powder coat adhesion without deep peaks.
Q4: Is SiC 88 OK for structural steel blasting?
A: Yes, it's cost-effective and efficient for heavy rust and scale removal.
Q5: Does ZhenAn supply both 88 and 120 mesh in high-purity grades?
A: Yes, we offer both mesh sizes in SiC 88 and high-purity/green SiC options.
Why Choose ZhenAn
Stable, Verified Quality – Controlled sourcing and batch inspection ensure consistent metallurgical performance.
One-Stop Product Range – Silicon carbide, ferro alloys, silicon metal, cored wire, zinc wire, Electrolytic Manganese Metal Flakes.
Custom Specifications – Flexible grades, sizes, and packaging to fit different production processes.
Proven Export Experience – Professional handling of inspection, documents, and international shipping.
Reliable Supply – Stable factory partnerships and dependable delivery schedules.
Fast Support – Quick quotations and practical technical guidance.
Strong Cost–Performance – Balanced pricing with real process value.
