Making a ring out of tubing.

[PTV]

Hello All, and Happy Thanksgiving to everybody here. I'm not sure whether the question should be posted here or in another category. But here goes anyway.
I'm needing to make a 12" diameter ring from 3/4" thin walled tubing. A tubing bender would get it most of the way, but how does one get rounded out at the ends to weld it together??? Would I need to make something like a wiring groove in a slip roll (only bigger) to finish it? Is there better ways of attempting this? I've never had need to attempt something like this before so I'm open to suggestions or advice on ways of doing this. Thank You

John