Quality and failure
Inspect welds before inflation. In a burst test the parent sheet should fail and the weld should hold. Nozzle leaks in service are often fatigue.
Figure: pillow plate quality problem examples.
Defects, leak test, repair
Large faults: dirt, gap, poor clamp. Small faults: pinholes, heat still in a tight loop, unstable start/stop. Test after welding then after inflation: visual, water hold, dunk, soap, helium if vacuum demands it. Field repair: depressurise, TIG; grinding out beats welding on trapped pressure. Never burst-test with gas.
