Molybdenum foils for pinch sealing into quartz are etched using shields which protect selected welding areas at each end from the action of the electrolyte. Etching provides feathered edges all around but leaves thicker areas under the shields to which the inleads and electrodes are welded without any need for extra tabs to facilitate welding or to increase the current-carrying capacity. In a preferred foil-inlead construction, the inlead and electrode have spade ends coextensive with the thicker areas in the foils to which they are welded.