I need to cut the end of the pipe and connect a 4" 90 elbow there
How do you rebuild those ?
In my case I am cutting short a ceiling pipe that ends like that and I need to connect there an elbow like the one below and then an air difused
As far as I understand it is not recommended that these lines shoud be present at the upstream end of a duct when joined with another one
So in this case I need to recontruct them at the end where I cut the duct
Best Answer
You’ll want a duct crimper to finish the end that way. Image below from google image search, which led to one on amazon. I don’t link it since products come and go.