Typical Minimum Penetration Times for different material
| Material | Form | Type of Discontinuity | Water-Washable Penetration Time* |
|---|---|---|---|
| Aluminium | Castings | Porosity, Cold Shuts | 5 to 15 min |
| Aluminium | Extrusions, Forgings | Laps | NR** |
| Aluminium | Welds | Lack of Fusion, Porosity | 30 |
| Aluminium | All | Cracks, Fatigue Cracks | 30, not recommended for fatigue crack |
| Magnesium | Castings | Porosity, Cold Shuts | 15 |
| Magnesium | Extrusions, Forgings | Laps | not recommended |
| Magnesium | Welds | Lack of Fusion, Porosity | 30 |
| Magnesium | All | Cracks, Fatigue Cracks | 30, not recommended for fatigue crack |
| Steel | Castings | Porosity, Cold Shuts | 30 |
| Steel | Extrusions, Forgings | Laps | not recommended |
| Steel | Welds | Lack of Fusion, Porosity | 60 |
| Steel | All | Cracks, Fatigue Cracks | 30, not recommended for fatigue crack |
| Brass & Bronze | Castings | Porosity, Cold Shuts | 10 |
| Brass & Bronze | Extrusions, Forgings | Laps | not recommended |
| Brass & Bronze | Brazed Parts | Lack of Fusion, Porosity | 15 |
| Brass & Bronze | All | Cracks | 30 |
| Brass & Bronze | |||
| Plastics | All | Cracks | 5 to 30 |
| Glass | All | Cracks | 5 to 30 |
| Carbide-tipped Tools | All | Lack of Fusion Porosity, Craks | 30 |
| Titanium & High Temp Alloys | All | not recommended | |
| All Metals | All | Stress or Inter-Granular Corrosion | not recommended |
