For his entry in a cake decorating, sugarcraft and baking expo, engineer Martin Raynsford decided to make an edible version of his laser cut marble machine kit. The contraption had to be scaled up and initial builds didn't quite go as planned, but the Edible Marble Machine worked well and managed to attract the judges' attention to take home a prize.
Raynsford began by making the Edible Marble Machine out of gingerbread, but the spicy build material started to sag after a few days so he switched to slabs of sugar paste. He mixed the sugar paste with tylo powder to sufficiently harden the slabs, but found that it took 36 hours for each sheet to solidify. That was far too long to wait, and he managed to cut drying time to 8 hours by borrowing a food dehydrator.
The marble machine parts were hand cut using laser cut wooden parts as templates and the edges painted brown to give them a laser-cut finish. A wooden frame was used to create the sugar paste spiral, and then left to dry and harden. The spiral was divided into four sections and mounted to an edible support frame.
Three sheets of sugar paste were used to make the gears, stuck together with sugar glue for a thickness of 20 mm (0.78 in), and hand cut into shape. Five holes were made in the big gear to hold the marbles as it turned. And those marbles are edible, too. They're jawbreakers, sprayed with edible silver airbrush paint and coated in clear cake glaze.
The stub at the center of both gears was strengthened using dried spaghetti and also coated in the cake glaze. More glaze was used for the gear teeth and the Edible Marble Machine was finished.
A hand crank is used to turn the small gear, which then turns the big wheel. When a hole containing a jawbreaker in the large gear meets the hole in the frame at the top of the spiral, a marble is released and rolls down the spiral before being stopped at the bottom. The marble gets loaded back in the machine when a gear hole appears at the bottom.
Raynsford's Edible Marble Machine took silver prize in the "Pushing the Boundaries" section at Cake International, the largest cake competition in the world. You can see it in action in the following video.
Source: M S Raynsford