In industrial sandblasting for heavy rust removal, selecting the right silicon carbide (SiC) abrasive - defined by mesh size and purity - directly impacts productivity, surface profile, and reuse potential. A common comparison is 88 mesh (88% SiC) versus 90 mesh (90% SiC). While their numbers differ only slightly, the mesh vs. purity trade-offs change how they perform on thick rust, mill scale, and heavily corroded steel.
At ZhenAn, with 30 years of experience supplying SiC for abrasive blasting, we break down which option is better for heavy rust removal and why.
1. Heavy Rust Removal: Key Requirements
When removing heavy rust and thick mill scale from structural steel, ships, bridges, or heavy machinery:
Fast material removal is critical to keep labor and equipment costs low.
Deep anchor profile is acceptable (and often desirable) to promote adhesion of subsequent coatings.
Abrasive durability matters - the grit must retain cutting ability over many cycles.
Contamination risk must be managed, especially on high-value steels or where coating integrity is critical.
The two controlling variables:
Mesh size → affects particle diameter, cutting aggressiveness, and profile depth.
Purity (SiC content) → affects wear rate, debris generation, and potential surface contamination.
2. Mesh Size: 88 vs. 90 - Coarse or Smaller?
Mesh number = openings per inch; lower mesh number = larger particle.
88 mesh ≈ 180 µm particles - coarser
90 mesh ≈ 170 µm particles - slightly finer
For heavy rust removal:
Coarser grit (88 mesh) cuts faster due to larger contact area and mass, removing thick rust and scale in fewer passes.
Finer grit (90 mesh) cuts slower but gives a shallower profile and smoother finish - better for lighter rust or final coating prep, not for heavy buildup.
Verdict for heavy rust: Pick the coarser (88 mesh) for higher removal rate and deeper profile.
3. Purity: 88% SiC vs. 90% SiC - High or Low?
88 mesh (88% SiC) → lower SiC content, more silica and free carbon impurities.
90 mesh (90% SiC) → higher SiC content, fewer impurities.
Impact in heavy rust blasting:
Higher purity (90% SiC) → more consistent cutting, less breakdown per impact, longer life in recycling systems. Fewer impurities mean less chance of leaving residue that could affect coating adhesion.
Lower purity (88% SiC) → cheaper per kg, but higher wear rate; impurities can cause irregular cutting and potential surface contamination, especially on stainless or critical steel.
Verdict for heavy rust: If abrasive reuse and surface cleanliness are priorities (e.g., marine, offshore, pipeline), pick higher purity (90% SiC). For one-pass, non-critical jobs, lower purity may be acceptable to save cost.
4. Combined Comparison for Heavy Rust Removal
|
Factor |
88 Mesh (88% SiC) |
90 Mesh (90% SiC) |
|---|---|---|
|
Particle Size |
Larger → faster removal, deeper profile |
Slightly smaller → slower removal, shallower profile |
|
SiC Purity |
Lower → higher wear, more impurities |
Higher → longer life, cleaner surface |
|
Productivity |
Higher (fast bulk rust removal) |
Lower (slower, finer cut) |
|
Surface Profile |
Deep anchor pattern |
Moderate anchor pattern |
|
Reuse Potential |
Lower (faster breakdown) |
Higher (more durable in recycling) |
|
Contamination Risk |
Higher (more silica residue) |
Lower (cleaner blasting) |
Best choice for heavy rust removal:
Maximum productivity → 88 mesh (88% SiC) if surface contamination and reuse aren't concerns.
Balanced productivity & durability/contamination control → 90 mesh (90% SiC) if abrasive will be recycled or if substrate is sensitive (stainless, high-strength steel).
Optimal for most industrial heavy rust jobs → often 88 mesh with higher purity (if available) is ideal; lacking that, 90 mesh (90% SiC) gives better lifecycle value.
5. Practical Selection Guidelines
Assess Rust Thickness → Thick, heavy rust → coarser grit (88 mesh).
Check Substrate Sensitivity → Critical metals → higher purity to avoid contamination.
Evaluate Reuse Plans → Recycling system → higher purity extends service life.
Consider Cost vs. Lifecycle → Higher purity may cost more/kg but reduces total abrasive consumption.
Match to Profile Spec → Deep profile for heavy coatings → coarser; moderate profile for paint → finer.
6. Industry Example
A shipyard removing heavy marine corrosion from hull plates:
Switched from 88 mesh (88% SiC) to 90 mesh (90% SiC) in recycling blast pots.
Result: 30% longer abrasive life, fewer surface inclusions, better coating adhesion, despite slightly slower rust removal.
For new plate prep where speed was critical, they used 88 mesh (88% SiC) for first pass, then 90 mesh for final cleaning.
7. Why Choose ZhenAn for Sandblasting SiC
30 years of experience producing consistent SiC abrasives for heavy-duty blasting
Full range: 88 mesh, 90 mesh, SiC 88, high-purity options
ISO & SGS certified for reliable quality and performance
Custom packaging for single-use or recycling systems
Global supply ensuring on-time delivery to blasting contractors & manufacturers
Conclusion
For heavy rust removal, 88 mesh is the better choice over 90 mesh because its coarser particles remove rust faster and create the deep profile needed for heavy coatings. Between 88% SiC and 90% SiC, higher purity (90% SiC) improves durability and reduces contamination, especially important for reusable abrasives or sensitive substrates. The ideal solution often combines coarse grit with high purity - if unavailable, 90 mesh (90% SiC) offers a good balance of life and cleanliness, while 88 mesh (88% SiC) maximizes raw removal speed for one-pass jobs.
For expert advice on SiC grit and purity selection for your sandblasting projects, contact our team at:
FAQ
Q1: Can I use 90 mesh (90% SiC) for heavy rust and still get fast removal?
A: It will be slower than 88 mesh, but if paired with high-pressure equipment, it can still handle heavy rust - just with more passes.
Q2: Does higher purity SiC really last longer in recycling?
A: Yes - fewer impurities mean less breakdown and more consistent cutting over multiple cycles.
Q3: Is there a big difference between 88 and 90 mesh in profile depth?
A: Yes - 88 mesh leaves a deeper anchor pattern, better for thick coatings; 90 mesh gives a finer finish.
Q4: When should I pick 88 mesh (88% SiC) over 90 mesh (90% SiC)?
A: When maximum removal speed is the priority and surface cleanliness or reuse is not critical.
Q5: Does ZhenAn supply 88 mesh with higher purity than 88%?
A: Yes, we can provide custom blends or higher-purity options to meet your performance needs.
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.
