Here is how to raise and form a copper bowl.
The first thing to do is cut a circle to the desired size depending on how big and how deep you want it. Always anneal between steps and after hammering to prevent cracking.
The second thing after annealing the copper disk is to dish it using a forming hammer and a wooden form. This adds a slight curve to the copper and gives you a starting shape to work with.
Find the center of the bowl and measure the size of the foot you want. After that measure 1/2 inch intervals from the foot to the outside of the bowl. Tip: Marker disappears during annealing, so make sure you scribe the lines so you can see them after the annealing. Another cool tip is when the marker disappears, the copper is properly annealed.
You want to hold the copper at a 30 degree angle to the stake and have the hammer hit just above the end of the stake at an angle. You want to start at the edge of the foot and work in a spiral pattern towards the end. when you finish a 1/2 inch section reverse direction to keep the bowl even and keep from creating problems. Anneal after 2 sections. The end of the bowl will warp, but when you get to that section you can correct it. It will take several passes to create the desired shape.
To smooth out the hammer marks use a Planishing Hammer and a Planishing Stake. After planishing use a Chasing Tool and a Shot Bag to create the ridges.