ASTM D972 Test Method forEvaporation Loss of Lubricating Greases and Oils
9. Procedure for Greases
9.1 Weigh the clean grease-sample cup and hood (Fig. 2) to the nearest 1 mg. Remove the hood and fill the cup with sample, taking care to avoid occlusion of air. Smooth the surface level with the rim of the cup with a straight-edged spatula. Remove with a clean cloth any grease which may remain on the rim or threads of the cup. Thread the hood tightly onto the cup without disturbing the smoothed grease surface. Weigh the assembly and record the mass of the sample to the nearest 1 mg.
9.2 With cover in place, but without the hood and sample cup attached, allow the evaporation cell to acquire the temperature of the bath (controlled to +/-0.5°C (+/-1°F)) at which the test is to be made by immersing the cell in the bath, as shown in Fig. 1a. Allow the cell to remain in the bath at least 1/2 h before beginning the test. During this period, allow clean air to flow through the cell at the prescribed rate, 2.58 +/-0.02 g/min (2 L/min at standard temperature and pressure), as indicated by the rotameter. Remove the cover, thread the weighed hood and sample cup into place, and replace the cover. Tighten the three knurled cover-tightening screws securely to prevent air leakage under the cover. Pass clean air through the cell at the prescribed rate for 22 h +/- 5 min.
9.3 Remove the assembled sample cup and hood from the cell. At the end of the 22-h period allow to cool to room temperature. Determine the mass of the sample to the nearest 1 mg.
10. Procedure for Oils
10.1 Weigh the clean oil-sample cup and hood (Fig. 2a) to the nearest 1 mg. Transfer, by means of a pipet, 10.00 +/- 0.05 g of sample to the cup. Assemble the cup and hood, being careful not to splash oil on the underside of the hood. Weigh the assembly and record the net sample mass to the nearest 1 mg.
10.2 Evaporate the sample as described in 9.2 and 9.3.
