Artist weds Scientist @ 6,000 Volts
By Heidi Kumao and Michael Flynn

Our rotating and sparking 6000-volt wedding cake was the highlight of our wedding ceremony because our collaboration on this project represented the way we approach our life together. A clay surrogate of each of us topped each motorized cake tower. Each time the two dolls would pass one another, a sizzling, 6,000 volt spark would jump and snap briefly between their outstretched hands.

The inspiration of our design was to make gear shaped cakes to symbolize the way our lives have meshed. But, we agreed, if we use gears as our symbol, then the cakes should actually rotate. So, each gear was made of 1/8” plywood accurately shaped on a laser cutter then laminated into 1” stacks. Both plywood gears were mounted on large, Lazy Susan (platter shaped) bearings. One of the gears was slowly driven by a 10-rpm electric motor. Simple, round cakes, decorated with shiny ball bearings (made of sugar) were placed on top of each rotating gear.

We decided that the traditional cake topper figures should be recognizable as caricatures of ourselves, and that on each rotation, a spark should jump between the hands of the bride and groom to represent our passion for each other. The spark was provided by a 6,000-volt neon sign transformer that was hidden below the cakes in the wooden, Wed-o-Matic box. Electric current traveled from the transformer all the way up to the dolls through electric motor brushes that scraped on the rotating Lazy Susan bearing. It was important to avoid arcing the current through the ball bearings themselves; so, the sliding electrical contact was made on the uppermost disc of each platter-shaped bearing.

BRUSH SCRAPES LAZY SUSAN
OUTPUT OF MOTOR FITS INTO PLYWOOD

TRANSFORMER AND MOTOR


SHORT JUMPER WIRE
Short jumper wires brought the current from the top plate of the bearing, up each doll’s leg, and out their arms.

We hacked open a hair dryer to get an invisibly thin and heat resistant wire to deliver the spark from each doll’s outstretched hand. The spark initiates when the dolls’ hands are 1⁄4 inch apart and continues to arc until the hands move over one inch apart. This is basically a Jacob’s ladder like those in Dr. Frankenstein’s laboratory except this one also rotates.

The caricatures of ourselves as bride and groom were assembled from Barbie and GI Joe dolls. We used oven-bake modeling clay to form the oversized heads for the dolls and we sewed the dolls’ clothes to match our real wedding costumes.


CAKE TOPPER DOLLS
TEMPERATURE RESISTANT WIRE
One of our Art Professor friends helped design the CAD file of the plywood gear shape. He also suggested that the cakes should be stacked into three separated tiers. His idea of mounting the cake platforms off-center gave our sculpture a much more dynamic and interesting motion.


ANTIQUE AMP METER

 

GIFT CARD SLOT IN FRONT OF BOX
We made a big plywood box to hide the transformer and to support the cake drive mechanism. We decorated this box with the word “WED-O-MATIC” in adhesive vinyl letters printed by a local copy shop. The cake support box included a slot for gift cards and an antique amp meter to view the fluctuating electrical current. We scanned and reprinted the indicator scale in the amp meter, replacing the bold font title, “WESTINGHOUSE”, with our new title “CAKE-O-METER”.

The completed machine was ready for its first test run only five days before the wedding. We chose to leave the drive motor’s frame ungrounded for fear of attracting the lightning bolt from the transformer to the motor. Forgetting that the neutral wire inside the motor windings also goes directly to ground, we energized the transformer at the full 12,000-volt setting. Impressive sparks traveled through the paint and quickly destroyed the wiring inside our special order, gear reduced motor! We didn’t have time to order, ship and debug a new motor. Luckily, Heidi always orders a spare; so we installed the only remaining motor and grounded the frame this time so that any stray sparks would be returned to ground without entering the motor windings. We chose to run the transformer at half power to mitigate the arcing across the painted surfaces and found the sparks remained adequate to jump between bride and groom.

This cake was too dangerous to leave plugged in and unattended so we demonstrated the full function of the cake only during the cake cutting ceremony. We played a fun, cartoon-style tune by Raymond Scott called, "Powerhouse" during the cake performance and wore oversized safety goggles for dramatic effect.

Spark fires between dolls' outstretched hands.
Cake Cutting
You can see the two-minute video of our 6000-volt wedding cake performance at:
http://www.heidikumao.net/wed.html