Not sure about framework, but I'm going back this week on a nursery run. I'll take a better look. I would think that they were "formed" on some kind of metal (?) pipe, then slipped off to add the legs. They seem to be a little light weight.
I just thought of them as "inspiration," since most of us don't have a welding set-up. I'd be snipping, gluing, and hammering onto a piece of dried mesquite wood!
