Replacing the first duct was a bit more of a challenge than I thought it would be. Still easy, just more time consuming than I initially thought. Of course it doesn't help that I like to take my breaks and move along the project at a slow pace, leaving me plenty of time to think each and every step through.
We start off this project with a 7" to 6" reducer, since the hardware store only had 6" y's and 6" t's that were available in the store that day. Of course we needed some foil tape to tape off all seems and some Duct Mastic Sealant for all the connections. All straight duct will be done with 6" x 5' round metal duct pipe, which offers less resistance then the preexisting flex, and using Woven Vinyl Hanger Straps to help support the duct along the way. We decided to use 6x6x6 wye's to go from the trunk to the run, adding in an adjustable elbow to help the run to be moved up out of the way. Continuing on with the 6"x5' round metal duct pipe, until close to the register vent, where I decided to use 6" Flex just to make the connection easy. Lets not forget to pick up a Duct Crimper, just to make your life easier, if you have to cut your metal duct pipe, you'll be glad you got this.
Everything said and done, this really was very easy to do, just a bit more time consuming than I thought. Being that this was my first time doing this, I spent maybe 2 hours of actual work time on this first step. With that in mind, I'd be comfortable stating that a novice (like myself) could comfortably do this in just a couple hours/vent. If you don't want to do a lot of math, just use the same diameter of the preexisting duct work, but move it out of your way, avoiding multiple sharp turns. Seriously, if you're going to wrap it around your chimney in a nice pretty spiral pattern, then call a professional, so they can bring you down to earth.
7" to 6" Reducer https://go.magik.ly/ml/jb76/
Foil Tape https://go.magik.ly/ml/jb7f/
Duct Mastic Sealant https://go.magik.ly/ml/jb7i/
6" x 5' round metal duct pipe https://go.magik.ly/ml/jb7k/
Woven Vinyl Hanger Straps https://go.magik.ly/ml/jb7l/