All penetrant materials, except solvent removers, used in performing pene-
trant inspection SHALL be listed on the QPL or SHALL be approved for
listing as evidenced by a letter of notification. Refer to paragraph 2.5.6.
Qualification procedures for penetrant removability follow the same pattern as the sensitivity qualification
procedures except that the reference system for all f luorescent penetrant systems is the lipophilic system for
the appropriate sensitivity level. Again, the reference dry developer is used in all processes. The
requirement is for a candidate penetrant system to leave no more residual penetrant than the same
sensitivity level reference penetrant system. Grit blasted stainless steel panels are used for the removability
tests. Background measurements taken at three spots are averaged to get a result used for comparison
purposes. As an example, the Level 2 f luorescent penetrant lipophilic system is used for removability tests of
all Level 2 candidate penetrant systems; the reference dry developer is applied in processing both systems.
Qualified Products List (QPL).
Quality of QPL Materials.
DOD activities SHALL perform quality conformance verification on incoming
penetrant materials as described in Section 2.8.5.
Listing of materials on the QPL does not guarantee that subsequent products of the same formulation will be
acceptable. Listing on the QPL merely indicates that the original raw materials, formulation and com-
pounding practice can result in an acceptable product. There are many factors and conditions involved in
compounding and manufacturing penetrants that can affect their performance. ASM 2644 includes an option
for a procuring activity to contractually require a manufacturer to provide quality conformance test results
and a sample of the material from the lot or batch to be supplied. The procuring activity itself has the option
of performing tests to verify the conformance of a material, whether a sample and test report is or is not
Knowledge of penetrant problems, even relatively minor ones, is essential for
improvement of the NDI program, the materials specification and the qualifi-
cation tests. Information copies of written correspondence concerning unsat-
isfactory penetrant materials SHALL be submitted to AFRL/MLS-OL (Air
Force NDI Office), 4750 Staff Dr., Tinker AFB, OK 73145-3317; DSN 339-
4931 and AFRL/MLSA, Bldg. 652, 2179 Twelfth Street, Ste. 1. Wright-
Patterson Air Force Base, OH 45433-7718.
Unsatisfactory materials SHALL be reported in accordance with T.O. 00-35D-54 (Air Force) or AR 735-11-2
(Army). A copy of the quality conformance test results SHALL be included as substantiating data.
Basic Penetrant Processes.
Abridged penetrant process f low charts illustrating the general process steps for the various penetrant
methods are provided in Figure 2-4 through Figure 2-7. Detailed descriptions of application procedures are
contained in later sections and paragraphs. The process f low charts contain reference locations for the
detailed information. Since the