Construction notes on this piece: The vase was originally built up in four sections, two for the base and lower body, one for the detail section, and one for the upper body and neck. The inside of each section (except for the inside of the flared lip on the top section) was turned to finished dimension. The lower three sections were then built up into a large open shape, sanded to a relatively smooth inside surface, and then finished with two coats of tung-oil sealer. The top section was finished similarly, and then glued onto the lower sections. The outside shape was turned with a live center holding the top end of the vase on center. Turning the inside shape on the lip and neck, working 20" from the faceplate, convinced me it was time to acquire a center steady.
Also, this piece is a good example of how scale drawings can fool you. I did a 2D "section" drawing on my computer, at full scale, of the 19.5" by 12" vase shape. I printed it out at 50% scale, so it would fit on one sheet of paper. While I realized intellectually that it was a 50% scale drawing, I didn't quite internalize how large the piece would be until I had the pieces cut and was gluing together the rings. I looked at one of the 12" 12-gons for the detail, and said to myself, "Holy cow, Russ! This thing's gonna be _HUUUUUUUUUUUUGE_!" And sure enough, it was. I've still got a ways to go to be putting out Ray Allen-sized pieces (Ray himself is probably about 6' tall, but what I really mean is that he routinely produces open vase forms that are 26.5" high by 30" in diameter. With 3000+ pieces, I might add). For one thing, my lathe won't do anything that big, unless I do the whole thing "outboard". But this is a _lot_ bigger than anything I'd tried previously. Just for laughs, I filled it with water, very briefly. It holds roughly 5.25 gallons (20 litres).