Product Data Sheet – ZYGLO ZP-5B

Aqueous Developer

ZYGLO® ZP-5B is an aqueous (water-suspendible) powder concentrate for mixing with water. It forms an opaque white coating on the test part surface, providing a contrasting background around penetrant indications. The more powder used in the suspension, the more opaque the coating.

Chemical product icon - developer


  • Higher concentration of powder gives a more opaque coating
  • Good colour contrast with red penetrants
  • Non-flammable


Defect location: open to surface

Ideal for:

  • Castings
  • Forgings
  • Welds
  • Leak testing
  • Pressure vessels
  • Aircraft
  • Petroleum pipelines
  • Power plant components
  • General metalwork

Defect examples:

  • Cracks
  • Seams


A blend of inert mineral pigments, surface active agents and corrosion inhibitors.

Specification Compliance

  • AMS2644
  • ASME B & PV Code, Sec V
  • ASTM E165/E165M-18
  • ASTM E1417/E1417M
  • MIL-STD-2132D
  • MIL-STD-271F

Product Properties

Form and colour White powder
Density 0.6 g/cm³
AMS 2644 class Form C – Type 1 and 2
Sulphur content
< 1,000 ppm
Chloride content
< 1,000 ppm
Corrosion Meets AMS 2644

Like all Magnaflux materials, ZP-5B is closely controlled to ensure batch-to-batch consistency, optimum process control and inspection reliability.

User Recommendations

NDT Method
Penetrant Testing
Storage temperature 10°C to 30°C
Usage temperature
5°C to 55°C
Cleaner SKC-S
Water-washable penetrants AL-4B, SKL-WP2, SKL-LT, ZL-15B, ZL-19, ZL-60C, ZL-60D, ZL-67B, ZL-56
Post-emulsifiable penetrants SKL-SP2, SKL-LT, ZL-2C, ZL-27A, ZL-37
UV lamps
EV6000, ST700

Instructions for Use

Before using any developer, ensure the test surface is clean, free from excess penetrant, and dry. Residue from water-based penetrants can be removed with a water spray; solvent-based penetrants by wiping with a solvent cleaner.

With visible penetrants, cracks will appear as red lines and porosity as spots. If you see a general reddish colour or pink film, that means the penetrant was not completely removed.

With fluorescent penetrants, indications will fluoresce bright yellow/green under UV light. If you see a general greenish film, that means the penetrant was not completely removed.

Apply by immersion dip, spray or flow on techniques (see below) for just long enough to completely cover the part.

Dry the part thoroughly. For best results, use forced warm air drying at around 60ºC. Remove from the dryer as soon as the developer is dry or it could bake on and be difficult to remove.

Allow a minimum of 10 minutes development time before inspecting the component.

After inspection, wash off the developer film with a water spray and, if necessary, a brush.

Spray or flow-on application
Avoid foaming as foam bubbles in the developer film can cause voids in the dried coating.

Immersion dip application
Make up a developer bath:

  • Ensure that the developer tank and the part to be tested are clean. Excess penetrant will contaminate the bath and shorten its life.
  • Fill the tank with the appropriate amount of water (see table below) that is no hotter than 50°C. We recommend using soft water or de-ionised water where possible.
  • Wearing a suitable filter face mask, slowly add the required amount of powder (see table below) while agitating the water.
  • Continue mixing until the powder is fully dispersed.
  • Regularly agitate the bath throughout the development process, to keep the powder particles in suspension.
  • Don’t leave the component in the bath for too long – this will reduce the sensitivity of the process by removing penetrant from shallow discontinuities.

We recommend the following concentrations for the make-up of your developer bath:

Penetrant type Concentration of powder per litre of water
ZYGLO 60 g

The concentration should be monitored on a regular basis to maintain the correct working strength is maintained. To do this, take a known volume of the bath, evaporate off the water and weigh the residue. The concentration can be calculated as follows:

For a 50 ml sample volume: Weight of residue (g) x 20 = Concentration (g per litre)

A less accurate method is to measure the specific gravity of the bath and cross-reference with the graph at the bottom of this page.

Packaging and Part Numbers

Part number 055C002

Packaging icon: 5Kg/11 litre plastic tub

Health & Safety

Review all relevant health and safety information before using this product. For complete health and safety information, refer to the relevant Safety Data Sheet.

Download this Product Data Sheet as a PDF
Graph of ZP-5B bath specific gravity versus concentration at 20C