First, I cut a piece of sheet 36" X 13". I "V'ed" out the bottom edge to form tabs. Then I folded 1/2 over on each end in opposite directions so they would interlock. This will be soldered later. Then I folded the tabs under 90 degrees. Next, I cut a round disc for the bottom. Mathematically, it should have been just a hair under 11 1/16, but in the real world it ended up needing to be 10 and 15/16. To make this, I used a dremmel with a circle cutter to make a 1/4 inch plywood template.
Next came my first mistake. I had calculated the top cone to be a 13" disc with a hole in the middle and a slit up to that. Then overlap and seam to make a cone. The idea worked perfectly, but it should have been a 14" disc to allow for tabs to go down inside the wall of the pot. I decided to quit there and start again fresh tomorrow. I should have plenty of copper to cut a new one.

Tomorrow is another day. I will continue this tread as I work on it.
Thanks for looking,
Tim