TinnerFlow™2nd YearDuct Assembly, Seams & JointsStandard Correction
The inside throat of an angled fitting can be under tension. Align and clamp the flanges before driving the cleat, and trim/detail only as approved.
On a tight rectangular 45°, the inside throat joint may not sit as relaxed as a straight duct joint. If the flanges are not compressed and aligned, the drive can buckle or pop off instead of sliding home.
Use clamps or tongs to flatten the joint, check the cleat length, and drive it square. If the cleat or flange needs field trimming, keep it clean and approved so the joint still seals mechanically.
Use this as training guidance. Foreman direction, approved drawings, project specs, manufacturer instructions, employer safety policy, and AHJ/code requirements always control the final answer.