Push the release button located on the forward portion of a five-blade crimper down to release the crimper handles.
Slide the open jaws of the crimper over one end of round duct pipe. Pull the handles together firmly to place a crimp on the end of the pipe. Move the crimper to align the last blade of the crimper with the lower section of the previous crimp. Repeat the process -- rolling the pipe as needed -- until one end of the pipe has a continuous crimp around its circumference.
Slide the crimp end inside a non-crimped end of duct until the depth of crimp rests inside of the other pipe.
Secure the crimped connection by running one #10 self-tapping sheet metal screw through the connection every three to four inches with a screw gun and a 5/16 inch hex head adapter.
Apply duct sealer to the screwed connection with a paint brush. Allow the duct sealer to cure for 24 hours before using the air conditioning system.