PRETESTING, CLEANING, PRECLEANING AND POSTCLEANING
PRETESTING, CLEANING, PRECLEANING AND POSTCLEANING.
Purpose Of This Section.
The treatment and condition of parts prior to inspection have a significant influence on the results of the inspection
process. Nondestructive inspection personnel must be aware of the pre-inspection surface treatment processes and their
effects on the penetrant process. This section provides the necessary background information but does not contain
enough information to permit selection of a cleaning process or to perform major cleaning operations. However, there
is information on pretesting and precleaning procedures which NDI personnel perform.
Pretesting is done to determine the compatibility of penetrant materials with parts made of a material that has no
history of being successfully inspected with liquid penetrants.
Cleaning, is the initial removal of soil, corrosion and paint accomplished by the corrosion control or cleaning shop.
Precleaning is the surface preparation performed by NDI personnel just prior to inspection, to remove light soils that
have accumulated during service or since major cleaning.
Postcleaning follows penetrant inspection to remove residual penetrant materials.
Purpose Of Pretesting.
Some nonmetallic parts, such as plastics, rubbers and plexiglass, may react with the oils and solvents contained in
penetrant inspection materials. These oils and solvents can cause swelling, softening, distortion, crazing, or other
surface effects resulting in damage to the part. The purpose of pretesting is to ensure that parts to be inspected will not
be damaged by penetrant materials. All nonmetallic parts that have not been previously inspected, and which do not
have approved technical or nondestructive inspection procedures, SHALL be pretested.
If necessary, the cognizant ALC NDI Manager or responsible engineering authority
should be contacted for assistance.
Some materials may not show effects until they are subjected to service conditions
(aging, cold, heat, moisture).