These bowls are commonly call Dizzy bowls. Fun to make, look very nice and will keep your mind limber.
Start by glutting block of multi colored wood of various thickness. I usually start with a 12" by 12" by 2.5" thick block. You can use any size and type of wood you chose.
Here is a block, I leave the middle unglued so I can use a band saw to cut the rings.
Cut boards on a band saw some were between 3/8" and 1/2" thick. You will need 4 broads, tape the boards together.
Draw the rings with a compass. Below is a picture is of an Excel Spread sheet I used to design the bowl and ring sizes.
Picture of the rings and board.
To glue the rings together tape one side and then spread the opposite side and add glue; close ring making sure the glue covers the entire surface, clean up excess glue and tape the opposite side.
Ring glued together.
Sand the rings, so they are flat and no defects. Any defect will show up in the bowl when it is turned. This drum sander is set up with 120 grit.
I used a couple of pipe clamps to make a vertical press. Brace the under side of the table and attach the ends of the clamps to the brace under the table. Use a level on the top brace to make sure that you are applying even pressure. It is very critical the stack be as straight a possible, there will always be a slight wobble and which can be turned out.
Make a segmented ring for the top.
Two glue-ups ready for turning.
It is very important that the bowl be supported while turning.
The thickness of the bowl will be about 3/16"; support both sides. Go slow a tool snag will bring tears.
This is a copy of an Excel Spread Sheet used to design the bowl. The offset is the change in the diameter of the next ring. A 1/2" offset will have steeper angle while a 3/4" offset will have a more open bowl. The bowl pictured above is a 3/4" offset. The 3/4" offset will be a very thin turning. The board number's; all the 1's will nest inside of each other and so on for 2, 3 & 4.