To install a duct start collar you need to first cut your hole in the duct and simply bend every 4th tab on the duct start collar then insert your start collar into the duct, and simply fold the remaining tabs over on the inside of the ducting.

Visit my "how to cut a round hole" video to become an expert!
   • Video  

The Sheet Metal Kid channel consists of how to's and tutorials on how to use HVAC and sheet metal hand tools as well as how to install duct and ventilation correctly. We are a highly interactive channel to help you with all your sheet metal and ducting installation.