ASTM D4636 test method for corrosiveness and oxidation stability of oils
ASTM D4636 Standard Test Method for Corrosiveness and Oxidation Stability of Hydraulic Oils, Aircraft Turbine Engine Lubricants, and Other Highly Refined Oils
8. Sampling
8.1 As this test method is performed on uniform, finished oils, no special sampling procedure is needed for this oil.

8.2 Preparation of Metal Specimens:
8.2.1 Collect the required number and types of specimens to be used in the test method. Measure the diameter of each specimen and specimen hole to the nearest 0.1 cm.

8.2.2 Clean and polish the metal specimen face surfaces and inner and outer edges using 240-grit abrasive paper. Examine surfaces to ensure that no pitting, etching, or other signs of corrosion are present when viewed at 20x under the microscope.

8.2.3 From this point, handle specimens only with forceps, ashless filter paper, or clean polyethylene gloves. Store specimen immersed in separate containers of acetone until ready for final polishing.

8.2.4 Finish polishing metal washer specimens or square metal specimens. Use either technique described in 8.2.4.1 or 8.2.4.3.

NOTE 2 - Square metal specimens are required by alternative Procedure 2 in 10.3.

8.2.4.1 Finish polishing with 400-grit paper to remove marks from previous polishing. A good technique is to place abrasive paper on flat surface, then rub the specimen with longitudinal strokes in a direction perpendicular to that used with 240-grit paper. Use a different sheet of paper for each metal type.

8.2.4.2 Swab polished specimens with n-heptane followed by acetone until a fresh cotton pad remains clean when wiped on the specimen.

8.2.4.3 Finish polishing both sides of each specimen to a mirror finish using 150-mesh silicon-carbide grit (held on an acetone-moistened cotton pad).

8.2.4.4 Clean all metal dust from each square by rubbing vigorously with clean pads of absorbent cotton until a fresh pad remains unsoiled.

8.2.4.5 Wash specimens in n-heptane, rinse with fresh solvent, and allow to air dry.

8.2.5 Store specimens in a dust-free place if to be used immediately or under n-heptane if there is to be delay before use.

8.2.6 Immediately prior to use, dry and weigh each metal specimen to the nearest 0.1 mg.

8.3 Oil Sample Size (Note 3 and Note 4):
8.3.1 The total sample requirement is 250 mL, 200 +/- 2 mL for test and 50 mL for pretest determination of viscosity and acid number.

NOTE 3 - An alternative Procedure 1, which deletes the requirement for periodic oil sampling throughout the test period may be specified. Alternative Procedure 1 requires an initial oil charge of 165 +/- 2 mL (see 10.2).

NOTE 4 - An alternative Procedure 2, which deletes the requirement for periodic oil sampling and requires square metal specimens instead of washer-shaped metal specimens may be specified. Alternative Procedure 2 requires an initial oil charge of 100 +/- 1 mL (see 10.3).

9. Preparation of Apparatus
9.1 Cleaning of Glassware (from Previous Run):
9.1.1 Rinse all glassware items and the air tube adapter with degreasing solvent to remove residual oil, and air dry.

9.1.2 Fill or immerse the sample tube, air tube, and the 9-mm glass spacers in carbon remover at room temperature until carbonaceous deposits are removed. Water rinse after removal.

9.1.3 Wash all glassware items and the air tube adapter with detergent. Rinse with water to remove detergent, and dry.

9.1.4 Fill and immerse all glassware items with glassware cleaning solution and soak for 3 to 16 h (see Note 5).

NOTE 5 - This cleaning procedure is only necessary in a referee situation unless a cleaning solution, which is satisfactory to all parties involved, can be used.

9.1.5 Remove glassware from cleaning solution, rinse several times with tap water followed by distilled water, and oven dry (see Note 5).

9.1.6 Store all items in a dust-free cabinet until needed for test. If stored longer than 1 week, rinse again before use with distilled water and dry.

9.2 Cleaning of Glassware (New) - Proceed as in 9.1.3 and 9.1.6 in that order (omit 9.1.1, 9.1.2, 9.1.4, and 9.1.5).

9.3 Assembly - Assemble as shown in Fig. 5, using only the test oil to lubricate glass joints during assembly.