Abstract: An electric work-in-circuit tool has a pair of fiber-reinforced plastic arms connected in tong fashion and limitedly opened by a spring. The free end of each arm has an integral flange apertured to receive bolts for assembling with, and attaching to the arm, a plurality of centrally apertured metal discs which are spaced by metal washers to form a heat-dissipating unit. The heat-dissipating unit spacedly surrounds the rear part of a metallic conductor body which has an axial bore to receive the bared end of an insulated power supply conductor passing axially through each tong arm. The conductor body also has a reduced-diameter front extension supportingly received in either a longitudinal or a transverse bore in the rear end of a metallic electrode holder whereby the electrode holder may be oriented either longitudinally or transversely of the conductor body. Each electrode holder has a longitudinally extending rabbited seat for dove-tailed slidable reception of a tapered carbon electrode-block.

Abstract: Porosity or other types of small leaks in metallic vessels designed to hold fluids under pressure or partial vacuum are repaired by: (1) sealing the chamber of the vessel, (2) introducing (preferably inert) gas at high pressure into the chamber, (3) immersing the vessel in a liquid (water) bath to locate and mark the leak(s), (4) mechanically cleaning the leak areas(s) while the gas pressure is maintained, (5) releasing the gas pressure and drawing a high partial vacuum in the chamber, (6) applying solvent to the leak area(s) to be suction-drawn through, and to clean, the leak(s), (7) while maintaining the partial vacuum, applying a liquid epoxy cement filled with a powdered metal compatible with that of the vessel, and (8) promptly heating the repaired area(s) to a moderate temperature and then releasing the vacuum. The repair will set in a few minutes and cure in several hours. The repair area(s) can be lightly abrasion-cleaned to remove any excess cement.