Testing Lipophilic Emulsifier

T.O. 33B-1-1 1-35 (9) Using tweezers, insert a quartered piece of filter paper into the cylinder mixture, withdraw the paper and set it aside to air dry. (10) When both filter papers (reference and in-use) are dry, compare the fluorescent brightness of the filter papers to each other under a blacklight. If a significant difference of fluorescent brightness is noted, the fluorescent properties of the in-use production line penetrant have deteriorated, and the fluorescent sensitivity will probably not be acceptable. Follow accepted activity standards to process and perform additional testing or to discard the contaminated/degraded material. (11) At the conclusion of the fluorescent brightness testing, clean the cylinder with acetone (Specification 0-A-51F), rinse with water, and again clean with acetone. Dry with clean filtered compressed air. c. Rapid Brightness Test (Field). A rough check of penetrant baths can be accomplished by comparing their appearance on an absorbent material, preferably the filter paper used in paragraph 1.5.5.2.2b above. Place a drop of the working bath penetrant on a paper towel. Place a second drop of penetrant from the reference standard near the drop from the working bath. When the two drops merge, examine under a black light for difference in color and brightness. 1.5.5.3 Testing Lipophilic Emulsifier. Penetrant is an unavoidable contaminant of lipophilic emulsifier. It is carried into the emulsifier on the surface of parts where it dissolves and is washed off during immersion and drain. Since emulsifier and penetrant are miscible in all concentrations, even small quantities of fluorescent dye will cause the emulsifier to fluoresce. The fluorescent brightness increases with increasing dye content, but it is impossible to visually estimate penetrant contamination by observation of the tank surface. 1.5.5.3.1 Emulsifier will continue to function when contaminated with penetrant; however, when the penetrant concentration reaches a certain level, the emulsification action slows and eventually stops. The military procurement specification requires a 4 to 1 mixture of emulsifier to penetrant to leave no more residual background than the uncontaminated emulsifier. 1.5.5.3.2 Removability Test. NOTE Grit blasting using 100 mesh aluminum oxide grit is required only on locally manufactured panels to roughen the surface and is only required one time. Normally ultrasonic cleaning or solvent cleaning is performed after grit blasting. a. In-use lipophilic emulsifiers SHALL be periodically tested for contamination. A two-inch by four inch, 16 gauge (0.060") annealed type 301 or 302 stainless steel panel is required. The panel SHALL be ultrasonically cleaned or vapor degreased and grit blasted on both sides using 100 mesh, aluminum oxide grit (not beads), using 60 psig air pressure, with the gun held normal to and approximately 18 inches from the panel surface. After blasting, the panel surface should be handled by the edges only and protected from contamination by wrapping in tissue paper. b. Immerse the panel in the working penetrant bath and allow it to drain for 10 minutes at approximately a 60° (±15) angle. At the end of the drain period apply working bath emulsifier to one half of the panel and reference standard emulsifier to the other half. Application may be either by pouring or immersion. If pouring is used, place a small quantity of both working bath emulsifier and reference standard emulsifier into separate containers that are suitable for pouring. Apply the emulsifier to the upper edge of the panel so it flows down across half of the panel face. This shall be done with the panel in an upright position. It is desirable to have the two emulsifier strips close together at the center of the