Non Destructive Testing // Magnetic Particles

Fluorescent Magnetic Oxide Particles
  • Particles are easily agitated, fast acting and produce defined indications
  • Particles meet specification requirements
  • Can be used with both stationary and portable magnetic test equipment
  • Water based suspension is non-flammable


DUBL-CHEK GW-1 is fluorescent magnetic oxide that is suspended in a highly refined light petroleum oil or water. The particles respond to magnetic leakage fields created by discontinuities in ferromagnetic material. Particles rapidly collect at leakage fields producing fluorescent indications under ultraviolet light.

Specifications Compliance

• MIL-STD-1949
• AMS 3044
• MIL-STD-271
• NAVSEA 250-1500-1
• NTR-1E
• ASTM E1444
• ASTM E3024

Physical Properties

Particle Colour: Green
Florescence: Yellow / Green
Specific Gravity: 0.4 g/ml
Particle Size: 1 – 12 µm (average 5µm)
Temperature limit: 0°C to 49°C


Oil Suspension: Use at a concentration of 2g/Lt of MPF. For best results, add a small amount of MPF to the powder and form a slurry prior to adding to the bath.

Water Suspension: The water must be conditioned before adding the GW-1 in order to disperse the particles, wet the test surface and inhibit corrosion. W5-C is the recommended conditioner and is added at 10g/Lt. GW-1 should be added at a concentration of 2g/Lt.

Settlement Test: The settlement test, using a pear-shaped centrifuge tube, is essential to check the particle concentration and contamination to the suspension. This SHALL be performed on the initial batch, an adjustment made to the concentration, or at each shift change.  The Settlement Test methods and particle concentrations can be found in relevant standards. The recommended volume is between 0.15 and 0.25 ml and will vary from one specification to another. (Read the settled particles that are fluorescent using an ultraviolet light.) The concentration may be adjusted by adding more MPF, water or GW-1 as required.
1. Clean the test surface and allow it to dry.
2. Ensure continuous agitation of the suspension.
3. Magnetise the area to be inspected.
4. Apply the suspension to the test part at a distance of approximately 150mm from the surface.
5. Allow the excess oil/water to run off the inspection area.
6. Inspect the surface under visible light.
7. Collections of GW-1 particles will reveal discontinuities at the leakage fields.
8. Clean and repeat the process, changing the orientation of the magnetising direction.

Ordering Info

1537/1LBS 450g
1537/12LBS 5.5kg