Cleaning Precleaning

T.O. 33B-1-1 1-28 1.5.2.13.1 Cleaning Precleaning. a. Verify that coatings have been chemically removed from the surface of the area to be inspected. b. Verify that the surface has not been sanded, blasted, scrapped, or otherwise mechanically disturbed. c. Verify that paint stripping residues or other inorganic contaminants have been removed. d. Verify that aerosol spray cleaner-remover is suitable for precleaning. e. Verify that time has been allowed for the precleaning solvent to evaporate. 1.5.2.13.2 Penetrant. a. Verify that spray nozzles are clean and free of dried or tacky penetrant. b. Verify that the aerosol can is shaken to distribute solvents prior to spraying. c. Verify that good spray technique is used, with the can moving smoothly at the proper distance from the part. d. Verify that brushes, swabs, and small containers used to apply penetrant are clean and free of contaminates. e. Verify that penetrant is applied in an even layer, not excessively thick, and free of runs. 1.5.2.13.3 Penetrant Removal. a. Verify that initial penetrant removal is done with clean cloth, folded between wipes to provide a fresh surface during each wipe. b. Verify that solvent is not sprayed or poured directly on the inspection area. c. Verify that final removal is accomplished with a clean cloth, moistened (not saturated) with solvent. The cloth must be folded over with each wipe. d. Verify that a black light is used to check for traces of residual penetrant during penetrant removal. 1.5.2.13.4 Developer. a. Verify that can nozzles are clean and free of caked developer. b. Verify that the can is agitated until all developer is in suspension. c. Verify that the developer coating is not excessively thick and is applied as several thin layer passes, rather than a single layer. d. Verify that the required dwell time is allowed after the solvent has evaporated. e. Verify that the developer spray pattern is uniform. 1.5.2.13.5 Inspection. a. Verify that the inspection area is shaded or shielded to reduce ambient light to acceptable levels.