Do not leave a stripped TDC/Ductmate corner bolt in place and hide the gap with sealant.
Check
Confirm which corner stripped and whether the flange is bent or misaligned.
Check gasket placement at the corner and whether the joint is pulling evenly.
Remove bad hardware and inspect the corner piece.
Use shop-approved replacement hardware/backing method.
Recheck clips, corners, and sealant after tightening.
Steps
Confirm which corner stripped and whether the flange is bent or misaligned.
Check gasket placement at the corner and whether the joint is pulling evenly.
Remove bad hardware and inspect the corner piece.
Use shop-approved replacement hardware/backing method.
Recheck clips, corners, and sealant after tightening.
Say this to your foreman
The corner bolt/nut stripped on this TDC/Ductmate joint at [location]. I checked gasket and flange alignment. Do you want replacement corner hardware or an approved backed-up through-bolt repair?