Immerse both panels n the working bath penetrant and allow them to drain for 10 minutes
supported at an angle from the horizontal of approximately a 60° (
Process the first panel through a 10-second pre-rinse, 10-second drain, 20-second immersion in
remover, 5-second drain, and 10-second rinse.
Process the second panel through the same cycle except double the immersion time in the
Examine the panels under black light.
Clean the panels.
b. When the remover is fresh and uncontaminated, neither panel should exhibit any background
fluorescence. As the penetrant level in the remover starts to build up, the short immersion time panel
will begin to show some residual fluorescence while the longer immersion panel remains free of
background. As the amount of penetrant in the remover continues to increase, the level of fluorescence
on the short immersion panel stabilizes and the longer immersion panel begins to show some residual
background. When the remover reaches its penetrant tolerance limit, there will be negligible difference
in fluorescence background on the two panels. The remover SHALL be changed at this point.
Rejuvenation by partial extraction and addition of fresh solution, as with lipophilic emulsifiers, SHALL
NOT be permitted due to the inability to control concentration.
c. If the performance check in paragraph 126.96.36.199.1.2a does not indicate remover degradation, determine if
penetrant is causing the background fluorescence by proceeding as follows using the same panels.
Immerse both panels in the working bath penetrant and allow them to drain for 10-minutes at a
60° (±1°) angle.
Process the first panel using a 10-second pre-rinse, 10-second drain, 30-second immersion in the
working bath remover, 5-second drain, and a 10-second rinse.
Process the second panel using the same procedures above, except using the reference remover.
Examine the panels under a black light.
If background fluorescence is present on both panels, the working bath penetrant is contaminated
and must be replaced. If the panel processed with the reference remover is free of background
fluorescence, and the other panel exhibits any background fluorescence, then the determination
can be made that the working bath remover has reached its penetrant tolerance limit and SHALL
Cleaning the panels is mandatory.
Spray remover solutions are normally only used once with the effluent being disposed of after contact with the part.
Contamination of the working solution is not a problem. However, the aspirator injection system, while simple and
inexpensive, requires frequent checks to assure that the proper concentration is produced. Concentration of remover in
the spray SHALL be measured whenever the aspirator or water pressure valve is adjusted and at the intervals prescribed
in paragraph 188.8.131.52. Measurement SHALL also be made whenever there is an unexplained change in background