Product Data Sheet – SPOTCHECK SKL-WP2

Water-Washable Visible Penetrant

SPOTCHECK® SKL-WP2 is a water-washable visible penetrant designed for large surface areas and rough surfaces where excess penetrant would be difficult to remove with a solvent cleaner or emulsifier. It can be removed with a water spray, either manually or with an automated process.

SKL-WP2 produces a visible red color contrast for discontinuity identification, and it has outstanding penetrating characteristics.

Chemical product icon - visible penetrant


  • Outstanding penetrating characteristics
  • Easy water-wash removal
  • Vivid, high-contrast color
  • Superior flaw resolution
  • Excellent reliability
  • Wide range of applications
  • Excellent controlled washability over a wide temperature range and variable dwell times.


Defect location: open to surface

Ideal for:

  • A production environment where many parts are inspected daily.
  • Castings
  • Forgings
  • Welds
  • Pressure vessels
  • Tubular goods
  • General metal work

Defect examples: cracks and leaks

NOTE: we do not recommend SKL-WP2 for inspecting plastic materials, as it may stain, soften or even dissolve the base material under test.

Specification Compliance

  • AMS2644
  • ASME B & PV Code, Sec V
  • ASTM D129
  • ASTM E165/E165M-18
  • ASTM E1417/E1417M
  • EN ISO 3452-1
  • EN ISO 3452-2 (Sensitivity Level 2)
  • MIL-STD-2132D
  • MIL-STD-271F


A blend of petroleum distillates, non-ionic surfactants and an oil-soluble organic red dye.

Product Properties

Form and colour Red liquid
Flash point > 93°C (bulk product)
Density 0.88 g/cm³
Corrosion Meets AMS 2644
Viscosity 8.0 mm²/s
Sulphur content < 300 ppm
Chloride content < 300 ppm
AMS 2644 class Type 2, Method A/C

Like all Magnaflux materials, our visible penetrants are closely controlled to ensure batch-to-batch consistency, optimum process control and inspection reliability.

User Recommendations

NDT Method Penetrant Testing, Visible
Storage temperature 10°C to 30°C
Usage temperature 5°C to 55°C (bulk);  -5°C to 50°C (aerosol)
Coverage 10 – 15m² per 400ml aerosol; 20 – 30m² per litre
Cleaner/remover SKC-S
Solvent-based developer SKD-S2
Water-based developer ZP-5B
Accessories Reference test block (part no. 070C001)

Instructions for Use

Ensure test part is clean and dry, and free from oil, grease and other contaminants.

Apply penetrant by immersion dip, brush, flow on, conventional or electrostatic spray. Cover the test area completely.

Allow penetration time. Minimum penetration time is 2 to 5 minutes, with 10 minutes being adequate for most situations. Lower temperatures thicken the penetrant and require longer penetration times.

Spray the component with clean water at 10°C to 40°C, or wipe with a lint-free cloth dampened with our SKC-S cleaner. Once clean, the component should be dried before a developer is applied.

Apply a thin layer of developer* to the surface and allow a minimum of 10 minutes development time before inspecting the component under white light. Indications will appear dark red against the white developer background.

* A developer is used to maximise sensitivity and provide a white contrasting background. Two types of developer can be used:

  • Solvent-based: quick-drying materials which are applied by spraying. The component under test must be dry before developer is applied.
  • Water-based (aqueous): can be applied by dipping or spraying. To maximise penetrant sensitivity, parts should only be exposed to aqueous developers for short periods of time. The component must be dried before inspection.

Developer residue can be removed either by wiping with a cloth or by a water and detergent wash. Penetrant residues can be removed by vapour degreasing or solvent soak.

Pre-clean component with cleaner SKC-S.

Apply penetrant SKL-WP2 to the clean component and allow contact time.

Use SKC-S or spray the component with water to remove excess penetrant.

Dry component, apply developer (SKD-S2 or ZP-5B) and inspect.

Packaging and Part Numbers

Part number 008A163 (x 10)

Packaging icon: 400 ml aerosol can

Part number 055C071 (x 4)

Packaging icon: 5 litre metal can

Part number 055C072

Packaging icon: 200 litre barrel

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