It definitely ain't stove pipe. A bungee ain't gonna hold up that much stove pipe if it's triple wall. Well, maybe it's more gas appliance exhaust.
I priced a chimney system to put a wood burning stove in my shop for wintertime activities such as brewing beer, tinkering with small engines, drinking the beer that I brewed while I'm tinkering, etc. JUST the chimney, no heater yet, $2500 bucks for less than 20 feet of chimney. Just a few more feet than the dude used on his redneck grass catcher. Needless to say, I don't have that wood burning heater yet. I'm not knocking the catcher at all, btw. I'm a yankee's worst nightmare. I'm a self-proclaimed redneck with an education. You ain't seen Bubbafied until I get started. Redneck ingenuity combined with an engineering degree is an amazing mixture, if not a little dangerous at times. I was going to do something similar with something flexible and put a screened box on my little yard trailer so I wouldn't have to empty the clippings until I was done cutting. It was mostly for picking up leaves in the winter, though, also making the wood burning heater a must have for warming up and drying out after cleaning up the yard on a typical Alabama winter day of 35F and light rain. If I could figure out how to make the chimney dual purpose..... Grass catcher chute by day, smokestack by night ....... Some kind of snap together arrangement to make it quick to convert. The grass clippings would take care of the creosote and soot removal from the chimney .... Dual use might just make it more feasible.