A takeoff hole cut too large or ragged may keep the collar from gripping clean metal. Before covering it or forcing the collar in, measure the opening and decide whether it can still be mechanically fastened and sealed correctly.
Ask when finish/exposed spiral, connection type, seal method, support, or fitting orientation is unclear.
Watch out
Do not try to seal an oversized takeoff hole with mastic or tape alone. The collar has to mechanically grip clean metal.
Check
Measure the actual hole you cut and compare it to the takeoff collar or saddle you are using.
Check whether the collar flange still has enough clean overlap to fasten and seal per the job standard.
If the collar is floating, barely catching, or sitting on ragged metal, do not rely on sealant alone.
Likely recoveries include a larger approved collar/saddle, a properly fabricated filler/patch plate with a correct opening, or remaking the duct section.
Photograph or mark the hole and collar before making the recovery so the issue is clear.
Steps
Measure the actual hole you cut and compare it to the takeoff collar or saddle you are using.
Check whether the collar flange still has enough clean overlap to fasten and seal per the job standard.
If the collar is floating, barely catching, or sitting on ragged metal, do not rely on sealant alone.
Likely recoveries include a larger approved collar/saddle, a properly fabricated filler/patch plate with a correct opening, or remaking the duct section.
Photograph or mark the hole and collar before making the recovery so the issue is clear.
Say this to your foreman
I cut this takeoff hole [size] and the collar is [size]. The hole is oversized or ragged by about . Do you want a larger collar/saddle, a patch plate with a correct opening, or should this section be remade?