Abstract: A combination spark plug gapping tool which has the capability of opening or closing the spark plug gap on a variety of aircraft, industrial, or automotive spark plugs. The single tool may be used with side electrode designs containing up to three electrodes, including both stud and wire electrode types. Also included is a sight gauge hole for visual checks of the center electrode, and a pointed end for scraping carbon. One end of the tool contains an offset two-pronged slotted fork which is sized to reach around the center electrode to open the gap by raising two side electrodes at a time. When turned over, the two offset prongs reach around the electrode being set and bear against the inner plug wall, thereby permitting gap closure by pushing. A center slot on the edge of the tool is used to adjust side wire electrodes.

Abstract: Aluminum electrolytic capacitor foil is etched in a bath containing 0.5 to 1.8 M hydrochloric acid, 0.2 to 0.5 M aluminum chloride, 0.03 to 0.3 M phosphoric acid, and 0.05 to 0.3 M nitric acid, the molar ratio of said nitric acid to said phosphoric acid being 0.3-5, while subjected to the action of alternating current at 28.degree. to 45.degree. C.