The base, feeder tube, chimney tube, and upper tub/grill are all separate pieces.
The first day I worked on the stove, I cut all the pieces to size and to fit each other. Here's what I had at the end of work day one (a couple hours of an afternoon)
The second work session, I did all the welding to put those pieces together.
The welder itself was a wire-feed welder (without gas).