Zyglo ZL-37 Post Emulsifiable Fluorescent Penetrant

ZL-37’s formulation has been designed to be impervious to water to protect it from over washing and permit more penetrant to remain in discontinuities for improved detection of small defects. It and other post emulsifiable penetrants require the application of a lipophilic or hydrophilic emulsifier to render them washable with water.


Zyglo ZL-37 fluoresces a bright greenish-yellow under ultraviolet radiation. Use of an ultraviolet light source with a peak wavelength of 365 nanometers, such as our ZB-100F fan-cooled black light, is recommended.

Specifications Compliance: 

AMS 2644F, ASME B & PV - Sec V, ASTM E-165/E-165M, ASTM E-1417/E-1417M, MIL-STD-2132D, MIL-STD-271F, Pratt & Whitney PMC 4354-2, Rolls Royce RRP 58003 (CSS 232), SAFRAN Pr 5000/In 5000.


Applications: Zyglo ZL-37 is ideal for titanium turbine components, investment castings and other high stress critical components where detection of fine, tight discontinuities is required.


Classification: Type 1, Method B Penetrant when using ZE-4B emulsifier.
Type 1, Method D Penetrant when using ZR-10C (20%) remover.


Sensitivity Level: Level 4 - Ultra-High Sensitivity.

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Part Number and Container Size


25 litre metal can



200 litre metal container