A local indoor percussion group (Team Percussion USA) needed props for their winter show. The requirements for the props were:
- Steampunk theme with animated 'Rube Goldberg' elements
- Break down for transport to events around Northern California plus cross-country to the Ohio championships
- Rugged and lightweight - to be rolled all around during the show and last the season
- Fit through a gymnasium doorway, but as large as possible to show well to crowds in the stands
- Inexpensive and available in a few weeks
We got right to work: sketching, discussing, then getting approvals by the group artistic directors. Everyone needs to pull together for the props, floor, costumes, and of course performance to gel.
Step 1: Design and Materials
Design and Breakdown of Each Element
The design settled on large flat gears and pipes mounted on three 2ft x 8ft plywood bases on casters. A ball would lift on the far left, roll down a ramp, across a tilting ramp on the second platform, then finally into a hinged basket on the third platform that triggered a flag popping open. There is a limit on animation that will work reliably on a 9 minute show (that includes setup and take down!). And you do not want to ever overshadow the performers.
The drawings were scanned and imported into Inkscape graphics program. Each element was redrawn on a separate layer with dimensions. Then the individual element could be scaled up to full size if desired, then printed on multiple 8.5" x 11" sheets with PosteRazor.
Bases - 2' x 8' x 1/2" plywood with castors. Two 2" x 2" x 8' wood beams screwed underneath took out any bow in the long plywood
Vertical pipes - 6" & 4" drainage pipe wrapped in silver duct tape - paint does not stick to HDPE plastic
Decorative pipes - 2" PVC pipes, fittings, PVC glue
Gears - 4' x 8' x 1.5" R-Tech rigid foam insulation, Titebond II wood glue and cheap cotton sheets from IKEA
Ramps and push handles - 1/2" EMC electrical pipe, welded with 2 rails for the ball ramp. Bent with EMC bender for the push handles. WARNING - grind off zinc coating and use approved respirator when welding EMC pipe
Misc. hardware - 1/2" and 1/4" threaded rod, nuts, bolts, angle brackets, sheet metal screws, plumbers tape, wing nuts
Finishing and gluing - acrylic paints, duct tape, spray paint, lots of Gorilla urethane glue
Step 2: Ginormous Gears
I used my foam cutter table (from Make magazine) to cut the gears. If you are cutting many identical gear teeth or parts, make a wood template to use as a guide, it is easier than freehand cutting. Strip the reflective mylar off the face side and the white mylar sheeting off where you are gluing things onto the back .
All of the gears had to spin freely by hand, but none needed to mesh together (by design). Lengths of cut threaded rod were used for axles - 1/2" for bigger gears and 1/4" for the smallest. We kept the number of different types of fasteners to a minimum since the props would be assembled at the venues under time pressure. Nyloc nut on one end and a wing nut on the other. Washers and spacers kept things spinning smoothly.
A circle of 1/8" plywood Gorilla glued to each side of the foam gear transferred the weight of the foam gear to the axle. I used nylon spacers glued into the gear as plain bearings on the fixed threaded rod axle. These would not last years but are fine for one marching season.
Two gears had pulleys attached, these were stacks of small and large plywood circles screwed to the plywood hub circle. One gear was cranked by a person to wind up a cord to raise the ball. The other was a high gear that spun with a pull of a cord, this needed to keep spinning so I used roller skate bearings in that gear. If you need these gears to turn for years or very fast, use this method.
Foam takes paint badly and can chip easily when bumped and transported. We have come up with a great solution for this - encapsulating the foam with cotton sheets that protects the foam and is paintable with acrylics or oils. It is still lightweight but much sturdier.
Make sure the mylar film is removed from the foam panel surface for good adhesion in the next step. Paint the gear front face with Titebond II wood glue and stretch an inexpensive IKEA white sheet on top. Cut and glue the fabric around teeth and any holes. Make sure there is enough fabric to wrap around the edges to the back by a few inches to protect all the teeth with glued fabric.
We used mostly acrylic paints; a base color then antiquing with other colors and black. Silver and gold paints can have drying problems because of their chemistry so be sure to test them out before committing to a large surface. Martha Stewart metallic glaze was terrible, it would stay tacky and never dry. Craft Smart metallic, Apple Barrel (Michaels), Martha Stewart acrylic paint, and Liquidtex were great.
Step 3: Extra Ginormous Gears
Each gear was unique and some were wider than the 4' foam width so I developed a technique to splice two sheet together structurally:
- The two parts were cut with the cut line as far to one edge as possible so it could be pinned easily
- Lay down the two parts flat on a table with wax paper underneath the joint so it doesn't stick to the table
- Wet the faces of the joint with water (to activate the glue) then liberally apply Gorilla glue to each half of the joint
- Clamp with bungie cords, urethane glue expands as it cures
- Push wood chopsticks or wood dowels through the foam at different angles to permanently pin the joint
- Trim excess glue with a hacksaw blade laid flat on the gear surface
- Cover with fabric as described in the previous step and the seam disappears
Step 4: Animation
The human powered animation took some planning and tuning until it worked without glitches. The key visual element is a painted basketball that is put in a wire basket, lifted, rolls down a ramp, then falls into a net and trips a flag to open. Feedback from the performers helped us get it dialed in.
Step 5: Finishing Up
We painted the plywood bases with 1 quart of Rust-Oleum Hammered Copper oil paint and they looked fantastic. The paint looks like it is curdling as it goes on but that just is the hammered effect happening as it dries, strangest thing to watch. They have it in spray cans too but I didn't try it. Very steampunk.
A large stationary gear was held in place by two 1/2" vertical galvanized pipes bolted to the plywood base. A photo above shows the rectangular sheet of plywood Gorilla glued to the foam with loops of parachute cord that slipped over the pipes.
PVC pipes painted nicely with the acrylic paints looked impressively industrial. Bare metal was rubbed with a rag dipped in black paint to take the shine off and give it an appropriately grubby look.
A trip to the Dollar Store gave us a few props: a dog bowl with a circle of cardboard and printed gauge hot glued in it makes a nice gauge. Serving trays spray painted and antiqued make gear centers. Fancy plastic dinner plates make flat gauges.
Now go start making your own giant gears and decorations!