I decided to make a prototype batch . You mix 2 parts cornflour, 3 parts water and 4 parts bicarb. Stir continuously whilst heating gently. It will turn to the consistency of mashed potatoes . Remove from heat, cool 30 mins. Knead till you have a ball of soft dough.
Now roll out to ¼" thick. Cut out shapes, making a hole with drinking straw . Either leave to air dry for 24 hours, or bake at 100'C for an hour.
36 hours later - I have a tray of air-dried discs, which are still soft enough to dent with a finger nail, and a second tray of oven baked discs which whilst hard and white[ish] on top have ugly yellow stains underneath.
That one is a failure. Perhaps I shall try again - with slightly less water, and roll them thinner than the previously ¼" [measured carefully by making a frame of narrow chopsticks to keep the pin ¼" above the surface] Using a cup measure, 250ml of cornflour etc yielded 15 discs.
Then there were the "popsicle bracelets" Boil some lolly sticks in a saucepan of water for an hour then curve gently into a circular shape. Push them into a drinking glass to hold their shape as they cool overnight.
Another epic fail. The instructions all say "make some spares to allow for a few sticks cracking" Yeah,right, 50% of mine split. Furthermore it was hard to curve them into a small circle, or to find a really small glass to support the cooling sticks.
They dried [eventually] into semicircles which wouldn't really stay on a child's wrist. More of them fractured during the drying process. I think the problem is two fold. Firstly these are relatively cheap wood, hence the splitting and second [and more significant] they are too short!
I used regular 11cm lolly sticks - what I really need are 18cm tongue depressors. Just so you know, the finished items are supposed to look like these...
I shall have another attempt at the clay, but I think I only have small sticks in the Great Stash. Ah well, back to the drawing board!