First I made a mold for the bowl. I lined a large cardboard box with plastic and put a hard plastic bowl upside down in it. The bowl came from the dollar store. I lightly coated the bowl and box with Murphy's oil soap which made it easier to come off the plaster.
The mixed plaster needs to be poured slowing into the box mold to limit air bubbles. The plaster was bought at a pottery supply place. Follow the directions on the plaster bag.
I put enough plaster to cover the bowl then put a coat hanger shaped in a circle over the plaster. The wire reinforces the plaster. A second batch of plaster was made which was poured over the first plaster in the mold. Plaster sets up fast so only make small batches. I was too slow with the first batch and it set up in the bucket.
Let the plaster cure for a day before taking it out of the mold.
My mold is quite heavy so I leave it on a shelf to make the bowls.
Making The Bowl
I first turn a bottomless cylinder. This becomes the base.
I roll out a large piece of clay that has been wedged, with no air pockets. It is laid in the plaster mold. With a soft rib I smooth the clay into the plaster mold. By this time it is dry enough to flute the edges, if desired.
The plaster dries the clay quickly. When the clay is leather hard I take it out of the mold, turn it upside down on foam, for protection.
When the base is leather hard cut the top of the base at an angle and place it on the bowl. This gives it more surface to attach it to and fit the bottom of the bowl. You might want to place a bubble level on it to make sure it will sit level. Mark where the base will fit. Slip and score the bowl and base. Attach the base to the bowl.
You can put a coil on the inside of the turned base to secure to the bowl. Flip it over and dry it under plastic.
Decorate it any way you want to.