Then I put two pieces of my thin foam together with paper tape (won't stick to clay) on my 12"x12" mat and cut out the design. Then applying packing tape to the foam before removing it from the mat, then removed whole double sheet before weeding, and applied packing tape to the other side, then weeded out design, with positive on one side with packing tape backing and negative on the other side:
I had seen a neat idea to give bowls a nice shape using foam wreath, but couldn't find any cheap enough, and then saw another idea using foam pip insulation to achieve same thing. My DH picked some up at hardware store and I found that trying to bend it into smooth shape with no kinks was difficult. So I stuffed the foam piece with plastic grocery bag until very firm, then cut and taped into circular shape. Here is a pic of the foam shape. --still had a slight kink, but was fine
Then I slabbed out some clay and while slab was flat, I pressed the negative foam cut, (see top picture, one at top is negative onto the clay using my hands and a credit card. You can see the process in this video (please mute speaker, I didn't realize there was so much annoying background noise:
Then cut around the scalloped edge and placed on top of the foam rings dropping on concrete floor to get them to slump (made two in very short order).
Here they are drying: