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P-C-111C <br /> 4.5. 15.2 Test procedure. Add approximately 25 ml. of the compound (see ' <br /> 4.5.14) to each test tube. Stopper the test tubes with cork stoppers, and <br /> place in an oven or bath at 54° ± 2°C. for 4 hours. At the end of this <br /> period, remove the panels from the tubes, wash thoroughly under running <br /> water, then with ethyl alcohol, dry with paper towelling and reweigh. Dis- <br /> coloration, pitting, and etching shall be noted. Check for compliance with <br /> 3.11. <br /> 4.5.16 Galvanic corrosion. <br /> 4.5.16.1 Preparation of panels. The panels shall be 1 by 1 inch square <br /> and approximately 0.03 inch thick except that the lead shall be approximately <br /> 1/16 inch thick. Metals tested shall include copper conforming to QQ-C-576, <br /> temper, cold rolled, light; magnesium alloy conforming to QQ-M-44; aluminum ' <br /> alloy 2024 temper T4 conforming to QQ-A-250/4; steel conforming to QQ-S-698, <br /> cold rolled, SAE 1020, half hard; and lead conforming to QQ-L-201. Make two <br /> holes in each panel, so that they may be fastened together, as shown in Figure <br /> 1. After the plates are polished, washed, dried, and weighed � (as prescribed ! <br /> in 4.5.15.1) , fasten them together by means of cotton string, making sure of <br /> good contact between metals. There shall be no contact between magnesium and <br /> lead or between aluminum and copper plates. Place each set of assembled <br /> panels in a 250-m1. beaker. Use four sets of assembled panels for the com- <br /> parison formula of 4.5.19.2 and four for the compound under test. <br /> 4.5.16.2 Test procedure. Add approximately 200 ml. of the compound (see <br /> 4.5.14) to each set of assembled panels. Cover beakers and place in an air <br /> oven bath at 54° ± 2°C. for 24 hours. At the end of this time, remove the <br /> panels from the beakers and rinse with water. Cut the strings and separate <br /> the panels. Wash panels under running water, then with ethyl alcohol, dry <br /> with paper towelling and reweigh. Discoloration, pitting, and etching shall <br /> be noted. Check for compliance with 3.12. <br /> 4.5.17 Clouding stability. Pour 10 ml. of the compound into a 100- by <br /> 15-mm. Petri dish. Let stand, uncovered, for 1 hour. At the end of this <br /> time, observe for clouding. <br /> 4.5.18 Inhibitor stability on evaporation. Place 50 ml. of the compound <br /> in a 100-m1. Griffin beaker containing a short stirring rod. Mark the level <br /> on the beaker. Let stand, uncovered, for 6 days, making up to the mark each <br /> day with distilled water. At the end of this period, filter the compound <br /> through shark skin filter paper to remove solid matter. Prepare one aluminum <br /> panel of QQ-A-250/2 as in 4.5.15.1. Immerse panel in the filtered cleaner in <br /> a test tube and observe after 30 minutes and also after 2 hours. Evolution of <br /> gas shall be considered as evidence of significant deterioration of corrosion <br /> inhibition. <br /> 4.5.19 Carbon loosening ability at room temperature. In the selection, <br /> cleaning and evaluation of pistons for the carbon loosening test, the top <br /> surface only of the piston sections shall be considered. <br /> ii <br /> 16 <br />