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Non Destructive Testing // Magnetic Particles

Visible Magnetic Particle
  • A unique 360° spray valve
  • Low background colour for high contrast indication visibility
  • Multiple spray patterns for controlled application and comfort
  • NATO Stock Number: 6850-01-88-9868
  • Particles are easily agitated, fast acting and produce defined indications
  • Can be used with both stationary and portable magnetic test equipment
  • Aerosols offer convenience and improve reliability


DUBL-CHEK BO-1 is Black Oxide No.1 black magnetic oxide suspended in a highly refined light petroleum oil. The suspension responds to magnetic leakage fields created by discontinuities in ferromagnetic material. Particles rapidly collect at leakage fields producing black indications.

Specifications Compliance

• ASTM E3024 • ISO 9934
• ASME B&PV Sec V       • MIL-STD-271
• AS 1171 • NAVSEA T9074-AS-GIB-010/271
• ASTM E709 • MILSTD-1949
• AMS 3041 • AMS 3043
• AMS 2641 • NATO Stock Number: 6850-01-88-9868

Physical Properties

Particle Colour: Black
Particle Concentration: 1.2 – 2.4 ml (i.a.w AMS 3041 & AMS 3043)
Particle Size: 0.5 - 4.0 µm, with an average size of 1.5µm
SAE Sensitivity: 6 lines
Suspension Fluid: Clear highly refined light petroleum oil or water
Viscosity: 2.64 cSt ± 5% (ASTM D445 @ 37.8°C±1°C)
Flash Point: ˃95°C (˃200°C)


1. Clean the test surface and allow it to dry.
2. Apply DUBL-CHEK CP-2 for background contras.
3. Ensure continuous agitation of the suspension. If using an aerosol, shake vigorously before and during inspection.
4. Apply the BO-1 suspension to the test part at approximately 150mm from the surface.
5. Apply the BO-1 suspension to the test part at approximately 150mm from the surface.
6. Allow the excess oil/water to run off the inspection area.
7. Inspect the surface under visible light.
8. Collections of Black Oxide No.1 particles will reveal discontinuities at the leakage fields.
9. Clean and repeat the process; changing the orientation of the magnetising direction.

Ordering Info

1503/400 Aerosol
1503/42 3.8 litres (1 gallon)
1503/51 18.9 litres (5 gallons)
1503/64 208 litres (55 gallons)