Downloaded from https://www.everyspec.com MIL-STD-1311D METALLIC BASE SLEEVE QUALITY METHOD 1131A (Acid etching test) 1. Purpose. This test is intended to reveal any evidence of subsurface hairline cracks in metallic sleeve of base with wafer insert. 2. Apparatus. a. Acid bath (for brass or bronze sleeves) 1 percent aqueous solution of mercurous nitrate to which has been added 3 milliliters of nitric acid (sp gr 1.42) per liter. b. Neutralizing bath. c. Salt spray (for noncorrosive steel sleeves). 3. Procedure. 3.1 Brass or bronze sleeves. a. Immerse the degreased, unplated sleeves into the acid bath with base wafer (insert) attached.
(Plated brass or bronze sleeves shall have the plating removed before starting this test.) b. After 15 minutes immersion, remove from acid bath, wash in neutralizing bath, wipe dry, and examine. 3.2 Noncorrosive steel sleeves. Substitute the salt-spray test method 1006 for the acid bath. 3.3 Rejection criteria. Upon completion of the test, any evidence of cracks in the sleeves shall cause the sleeve to be considered a failure, and the lot shall be rejected. 4. Samples. Three samples from each lot or shipment of sleeves shall be tested. METHOD 1131A 1131-1 25 March 1970