Post Emulsifiable Penetrants - Uses and Applications

Post emulsifiable penetrants are used when removal of the penetrant from the defect due to over-washing of the part is a concern. These parts usually have smooth surfaces and perform critical functions which require higher sensitivity to smaller defects.

Applications

Specifically, Post Emulsifiable Penetrants are ideal for:

• Parts with smooth surfaces
• Parts that perform critical functions which require higher sensitivity to smaller defects
• Detection of wide, shallow defects
• Applications requiring more controlled removal of penetrant from the part surface

Key Advantages

• Higher sensitivity to smaller defects
• Shows wide, shallow defects
• More controlled removal of penetrant from the part surface

Methods Available

Post emulsifiable penetrants come in two main methods:

• Method B: Uses lipophilic (oil-based) emulsifiers
• Method D: Uses hydrophilic (water-based) emulsifiers

How They Work

Post emulsifiable penetrants require a separate emulsifier or remover to break the penetrant down so the excess penetrant can be rinsed off with water, while the penetrant in the indication stays put.

This makes them particularly valuable for critical inspections where you cannot risk washing away penetrant from actual defects, unlike water washable penetrants which can be over-washed and lose shallow indications.

Magnaflux Post Emulsifiable Penetrants

Magnaflux offers three main post emulsifiable fluorescent penetrants in their product line:

1. Zyglo ZL-2C

• Level 2 post-emulsifiable fluorescent penetrant for Method B, Method C and Method D liquid penetrant testing, QPL SAE AMS 2644 and Pratt & Whitney approved
• A medium sensitivity penetrant (Level 2), ZL-2C fluorescent post-emulsifiable penetrant is designed to be removed from the part surface by emulsifiers or solvent. With a UV-A light source, indications will appear as a bright green-yellow fluorescence. ZL-2C has a high flash point, and is designed to be used in open dip tanks

2. Zyglo ZL-27A

• Level 3 post-emulsifiable fluorescent penetrant for Method B, Method C and Method D liquid penetrant testing, QPL SAE AMS 2644 and Pratt & Whitney approved

3. Zyglo ZL-37

• Level 4 post-emulsifiable fluorescent penetrant for Method B, Method C and Method D liquid penetrant testing, QPL SAE AMS 2644 and Pratt & Whitney approved

Additional Post Emulsifiable Product

4. Spotcheck SKL-SP2

• Solvent removable visible penetrant for Type 2, Method B, Method C and Method D dye penetrant testing, QPL SAE AMS 2644

Compatibility

All of these penetrants are compatible with Method B (lipophilic emulsifier), Method C (solvent removable), and Method D (hydrophilic emulsifier) processing methods, and they are all qualified under SAE AMS 2644 standards with several also having Pratt & Whitney approval.