Downloaded from https://www.everyspec.com MIL-STD-1311D PERMANENCE OF MARKING 1. Purpose. These tests are designed to control the quality of marking such that a specified degree of resistance to moisture and abrasion is maintained. The tests are not required on marking made by etching or grit-blasting. 2. Sampling. Sampling shall be as specified in MIL-PRF-1, section 4. 3. Procedure. a. Ink marking on glass or glazed ceramic surfaces. The tube marking to be tested shall be immersed in room temperature water for 2 minutes immediately prior to test. The tube shall be turned through 15 revolutions or submitted to 15 rubs (.500 inch minimum travel each), with the marked area in contact with No.
00 steel wool under a load of 500 grams. The active surface area of the steel wool (that area of the steel wool pad which is in direct contact with the tube and supports the 500 gram weight) shall be limited to not more than 1 square inch. The pad thickness under the load shall be approximately .500 inch. A new pad shall be used after a maximum of 15 tubes have been tested. b. Marking on other than glass or glazed ceramic surfaces and other than ink marking on glass or glazed surfaces. The marking on the tube shall be rubbed 12 times with a water dampened chamois exerting a force of approximately 10 pounds. c. Marking on tubes with integral permanent magnets.
Steel wool shall not be used on tubes which have integral permanent magnets, because of retention of metal slivers. Follow procedure (a), but substitute a woven nylon scouring pad in place of steel wool. 4. Acceptance criteria. A defective tube shall be defined as one on which any portion of the tube number, lot identification, or service life guarantee markings are illegible following the test. 5. Disposition of samples. Those tubes which successfully complete the test may be returned to the lot. Those tubes which fail the test shall be remarked and retested prior to being returned to the lot. METHOD 1105 METHOD 1105 1105-1 19 April 1968