Connecting to Sheet Metal
- Measure and mark the needed length of the duct.
- Cut through the plastic and insulation of the duct with a utility knife or scissors.
- Cut the wire with wire cutters and pull back the plastic and insulation.
- Slide at least 1 inch of the center of the flexible duct over the hole on the sheet metal duct. Wrap two layers of duct tape over the joint to seal it, then place a hose clamp over the joint and tighten it.
- Pull the plastic and insulation back over the wire core and secure it with two wraps of duct tape.
Splicing to Flexible Duct
- Fold back the plastic and insulation on two pieces of flexible duct.
- Connect the two pieces of flexible duct with a 4-inch metal sleeve.
- Wrap duct tape twice around the spot where the ducts connect.
- Place a hose clamp on each duct where it comes into contact with the metal sleeve and tighten the hose clamps.
- Pull the plastic and insulation back over the wire core and cover the seam with duct tape, making two passes.
Things You Will Need
- Tape measure
- Utility knife or scissors
- Wire cutters
- Duct tape
- Hose clamp
- 4-inch metal sleeve
- Allow the flexible ducts to run for no more than 5 feet without being supported by a ceiling joist or hangers.
- Handle the duct carefully so you don't tear it.
- Avoid bending the ducts around sharp corners.