Sandblasting

Sandblasting (abrasive blasting) uses compressed air to propel abrasive media at high velocity to impact and clean workpiece surfaces. This process effectively removes rust, scale, oxidation, old paint, and other contaminants, creating a textured surface ideal for coating.

Process Overview

The sandblasting process consists of these key steps:

• Surface Assessment: Inspections for heavy corrosion and pre-cleaning of grease or oil.
• Media Selection: Abrasives are chosen based on the task, such as aluminum oxide for general purposes or steel grit for heavy rust.
• Blasting Setup: Parts are processed in blast cabinets or rooms with full operator PPE.
• Operation: Compressed air (60–120 PSI) accelerates media through a nozzle, maintaining a distance of 100–300 mm.
• Cleaning/Inspection: Surfaces are cleaned of dust and verified against standards like SSPC-SP 10 / Sa 2.5.

Benefits

1. Contaminant Removal: Eliminates rust, mill scale, and welding residue.
2. Coating Adhesion: Creates an "anchor pattern" that increases mechanical interlocking for paints and coatings.
3. Versatility: Roughness can be precisely tailored (Ra 1.6–12.5 μm) by adjusting media and pressure.
4. Efficiency: Covers large areas quickly, making it ideal for structural components.
5. Material Compatibility: Applicable to ferrous metals, non-ferrous metals, castings, and forgings.

Design Considerations

Cleanliness Standards: Reference standards like SSPC-SP 10 in specifications to avoid improper blasting.

Geometry: Design for accessibility, as deep recesses or enclosed cavities can trap abrasive media.

Material Loss: Sandblasting typically removes 0.02–0.1 mm of material; ensure designs account for this or include post-blast machining allowances.

Corrosion Protection: Because blasted steel is highly reactive, apply primer within 4 hours or use rust inhibitors if storage is required.

Technical Specifications