NMWR-9-2815-220 Overhaul Manual for M60 M88 Engine AVDS-1790-2CA, AVDS-1790-2DA, AVDS-1790-2DR Download
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NMWR 9-2815-220 GENERAL MAINTENANCE, OVERHAUL, AND REPAIR PROCEDURES—Continued 0005 00 DIAGNOSTIC AND AUTOMATED TEST EQUIPMENT - Continued (3) Removal of Penetrant. Penetrants shall be removed in accordance with requirements for the type and method of liquid penetrant inspection. (a) In Method A both types I and II penetrants shall be removed by rinsing with water. (b) In Method B, an emulsifier must be applied to post-emulsified penetrants which are to removed by water spray. (c) In Method C, types I and II penetrants shall be removed by solvents. 1 The surplus penetrant shall be first removed with a clean, lint-free, dry cloth. 2 The background color, or fluorescence, shall then be removed by wiping with a cloth dampened (not wet) in solvent. 3 The penetrant shall not be flushed from the surface with solvent. NOTE Refer to ASTM-E-1417 for specific instructions for removal of penetrant. (4) Application of Developer. Developers are materials, wet or dry, which will draw or absorb penetrant from a surface crack or defect to the extent the defect will be visible under natural, artificial, or black light, as applicable. (a) The maximum elapsed time between penetrant removal and application should not be over 10 minutes. (b) Types of developers are as follows: 1 Aqueous wet developer for types I and II penetrants shall consist of a mixture of developer powder and wetting agents mixed in water. Application may be by spraying, immersion, or flowing. 2 Nonaqueous wet developers shall consist of a powder suspended in a volatile vehicle and can be used with all types of penetrant. Application shall be by spraying, if possible, but may be applied by brushing. 3 Dry developer shall consist of a light powder to be applied after drying the part. (The part must be dry). Application may be by dipping, dusting, or pouring, and the remaining surplus may be gentle tapping, or blowing with dry, low-pressure air. (c) All developers shall provide a good contrasting background to the penetrant for which intended. (d) A thin layer of developer is more sensitive than a thick layer. Thick coatings must be avoided. (e) Liquid developers and/or spray cans must be frequently agitated by stirring or shaking. (f) The developer must remain on the part for a minimum of one-half the penetrant dwell time but not more than 30 minutes. 0005 00-19 Change 1