To repair a duct on an air conditioner, make a soap and water solution, wash the damaged area, and apply aluminum sealing tape in layers around the damaged part of the duct. Required items include aluminum tape, a putty knife, soap and water. Scissors are needed to cut excess tape.
The first step is to mix dish soap and water in a bucket to form a solution. A rag should be used to thoroughly clean the damaged part of the duct, and then the duct should be left to dry completely. The next step is to cut six inches of Underwriters Laboratory 181 Approved aluminum sealing tape, remove the backing and apply it a few inches above the hole. Next, six more inches should be applied, overlapping the edge of the first tape slightly.
This process of applying aluminum tape should be done until the hole is covered by at least three passes, each with overlapping edges. In between each pass, it is important to use a putty knife to press the tape down, sealing it tightly. After the hole is thoroughly covered, the excess tape should be cut with a pair of scissors. Small holes can be sealed by applying caulk directly into the hole and allowing it to dry.