Staurolite is a heavy iron-aluminum-silicate mineral with low free-silica content. Comparable production to coal slag at silica-free compliance levels. Mohs 7.0–7.5, density ~140 lb/ft³. Common substitute for slag in silica-restricted job sites.

Four causes account for almost all post-blast coating failures:

1. Wrong profile. Coating data sheet says 3–5 mil; you delivered 1.5 mil. Coating wets the substrate but can't anchor.
2. Soluble salts. Chloride contamination on the substrate — common on marine and pipeline work. Test with Bresle patch.
3. Flash rust. More than 4 hours between blast and coat in humid Gulf Coast environments. Coat sooner or use a holding primer.
4. Surface still dirty. SP10 means 95% clean — if you have 30% staining, your spec calls for SP5.

Depends on the media:

• Steel grit/shot — 100–200 cycles in a closed reclaim system. The economic standard for blast rooms.
• Aluminum oxide — 4–8 cycles.
• Garnet — 2–4 cycles.
• Nickel slag — 1-2 cycles.
• Coal slag — single use. Breaks down on first impact.
• Glass bead — 4–6 cycles for peening, fewer for cleaning.

Steel shot is spherical (not angular) carbon steel. Used for cleaning without profiling — the ball impacts work-harden the surface without cutting an anchor pattern. Standard applications: peening for stress relief, cleaning of weld scale where re-profiling isn't required, and reclaimable blasting where consumption cost matters most.