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Slide 002: Blasting Techniques for Different Materials

Slide Visual

Blasting Techniques for Different Materials

Slide Overview

This slide covers how to adjust blasting parameters — pressure, angle, standoff, speed, and media — for different substrate materials and project goals.

Instruction Notes

The Five Variables of Blasting Technique

Every blasting operation is controlled by five adjustable variables:

  1. Pressure: Higher pressure = more aggressive cutting. Start low, increase incrementally.
  2. Standoff distance: Distance from nozzle tip to workpiece. Closer = more concentrated; farther = wider, softer pattern.
  3. Angle of attack: 45° for cutting/cleaning; 90° for peening/compressing; 15–30° for light sweeping.
  4. Travel speed: Slower = more material removal per pass; faster = lighter, more uniform coverage.
  5. Media type/size: Covered in M1; the foundation of all technique decisions.

Material-Specific Technique Guide

Mild Steel and Iron - Pressure: 60–80 PSI | Media: Aluminum oxide 60–80 grit - Angle: 45° | Standoff: 6" | Speed: 2"/sec - Notes: Most forgiving substrate. Watch for flash rust — coat within 4 hours.

Aluminum and Soft Alloys - Pressure: 30–50 PSI | Media: Glass bead 100–170 mesh - Angle: 45–60° | Standoff: 8–10" | Speed: 3"/sec - Notes: Reduce pressure significantly. Aluminum oxide embeds in soft aluminum. Glass bead preferred for cleaning without profile damage.

Stainless Steel - Pressure: 50–70 PSI | Media: Glass bead or aluminum oxide 100+ grit - Angle: 45° | Standoff: 6–8" | Speed: 2"/sec - Notes: Use only stainless-compatible media. Carbon steel media causes iron contamination and future rust spots.

Glass and Ceramics - Pressure: 25–40 PSI | Media: Aluminum oxide 120–180 grit - Angle: 90° | Standoff: 10–12" | Speed: 1"/sec - Notes: Very fragile — low pressure is critical. Excellent for decorative frosting. Mask patterns with vinyl resist for designs.

Wood - Pressure: 15–30 PSI | Media: Glass bead 70–100 or walnut shell - Angle: 30–45° | Standoff: 12–14" | Speed: 3–4"/sec - Notes: Blast with the grain. Soft media only — hard media destroys wood fibers. Creates beautiful weathered texture for signs and furniture.

3D Prints (FDM/PLA) - Pressure: 20–40 PSI | Media: Glass bead 170–325 mesh or baking soda - Angle: 45° | Standoff: 8–10" | Speed: 2"/sec - Notes: Low pressure critical — PLA softens under impact heat. Excellent for removing layer lines and support marks.

Key Talking Points

  • Always start with lower pressure and gentler media — you can increase aggressiveness but cannot undo damage
  • Substrate material determines your maximum pressure and media hardness
  • Angle of attack is the most overlooked variable by beginners
  • Keep a technique log for repeatability

Learning Objectives (Concept Check)

  • Select appropriate blasting parameters for six common substrate materials
  • Explain why aluminum requires different media than steel
  • Demonstrate how to adjust technique from aggressive cleaning to delicate finishing

Last Updated: 2026-03-19