The first hermetically sealed models were the P8-9-10 of 1971 using titanium encapsulation with ceramic terminal insulation, developed by David J Cowdery. Bonding of the ceramic was performed using vacuum brazing and an alloy of titanium/nickel with a small percentage of copper. The final hermetic sealing of the titanium capsule was performed by a TIG argon welding process within a large bell jar on an automated analogue controlled machine designed and built by Cowdery. These were the first pacemakers using the conventional battery to be hermetically sealed. Gas products of the battery were absorbed by a chemical 'getter'. Some examples of these models survived to beyond 5 years. By the late 80's TIG welding was replaced by laser welding.