[malfunction]

I'm about to cut a hole in my HVAC duct as well. The difference between me and jughead is I want to subtract instead of adding. I am removing two of them and replacing them with one. So how do you cover up the hole in the duct you are removing? I am talking about where the duct connects to the huge main duct. There will be a hole in it when I remove the duct.

 

[malfunction]

Sheet metal plate.

With what, rivets?