Non Destructive Testing // Magnetic Particles

DUBL-CHEK GW-8 fluorescent yellow-green particles premixed with powdered Wetting Agent for use in water media. It is designed to be used with ultraviolet light to detect very fine discontinuities in finished products. The Wetting Agent is low foaming and has excellent wetting characteristics.

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

Preparation: DUBL-CHEK GW-8 should be used at a concentration of 5 grams/litre of water. For best results, add a small amount of water to the powder and form a slurry prior to addition to the bath. When using the scoop provided with the DUBL-CHEK GW-8, one level scoop treats 3.8L of tap water.

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 water or GW-8 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 water to run off the inspection area.
6. Inspect the surface under fluorescent light.
7. Collections of GW-8 particles will reveal discontinuities at the leakage fields.
8. Clean and repeat the process, changing the orientation of the magnetising direction.