Exploding Cuckoo Clock - "Crazy for You" Musical

In one scene in the Gershwin-based musical, "Crazy for You", someone shoots a cuckoo clock, and the clock explodes. This Instructable describes my process for designing and building the exploding cuckoo clock prop.

This was the last high school musical that my daughter was in. She and I like to go to thrift shops to find parts for props or in her case, clothes, to repurpose for costumes. Whenever she went to the clothes aisles, I would always joke and say that I am going to the "Cuckoo Clock" aisle. After going to about 10 thrift stores, I finally found a cuckoo clock...but it wasn't in the "Cuckoo Clock" aisle, it was in the wood decor aisle! I saw it in the corner of my eye, did a double take, went over and grabbed it. I was so excited. Now, whenever we go to a thrift store, I revive my Dad joke that I am going to the "Cuckoo Clock" aisle; never gets old (for me); brings back fond memories of this show. But I digress...

The prop must be safe, and robust; it must be able to be reset easily, and work all of the time. This project taught me a lesson of scale, which I will discuss later.

Materials

• (Optional) Cuckoo Clock - for the bird whistles and decorative items.
• Cuckoo Whistle - If you can't find a cuckoo clock, there are other sources for cuckoo whistles, e.g., https://www.amazon.com/Acme-4858-Cuckoo-Whistle/dp/B000EEJANA/
• Cuckoo Clock Parts - e.g., https://frankenmuthclock.com/collections/parts-cuckoo-clock-quartz-cuckoo-miniature
• 1x6 Pine Boards - for cuckoo clock frame.
• 1/2-in. Plywood - for clock front and clock face.
• String
• Miniature Slinky - https://www.amazon.com/Slinky-Brand-Original-Multi-Color-03160/dp/B08QDMV4GM/
• Small Decorative Bird - Approximately 3-in. long, and 1-1/2-in. tall, e.g., https://www.michaels.com/pinson-dashland/10309954.html
• Drawer Slide - This is used to hold, and move the bird. The length must be long enough to extend from face of clock to several inches behind the wall on which the clock is mounted. Mine was from a broken dresser drawer; 15-in. long, which I cut down. Maybe something like this will work: https://www.amazon.com/Accuride-1029-Slide-13-length/dp/B001DT53HC/. Alternatively, use a small strip of wood to hold, and move the bird.
• 1/2 in. Pipe Straps - These are used to hold the spring & string in place - https://www.lowes.com/pd/Oatey-10-Pack-1-2-in-Galvanized-2-hole-Pipe-Strap/1001120420
• Nuts and bolts for the pipe straps, e.g., at least 1-1/2-in. long.
• 3/4-in. One-hole Strap Conduit Fitting - This is used to hold the trigger mechanism pipe - https://www.lowes.com/pd/Sigma-Electric-ProConnex-3-4-in-One-hole-Strap-Intermediate-Metal-Conduit-Compatible-Galvanized-Rigid-Conduit-Compatible-Rigid-Metal-Conduit-Compatible-Conduit-Fitting/1000152565
• Screws (various sizes) - to attach the pieces together.

Tools

• Saw
• (Optional) T-Bevel - To transfer angles. https://www.amazon.com/IRWIN-Tools-T-Bevel-ABS-1794475/dp/B005XUHJLK/
• Driver with Phillips bit.

I was lucky to find a non-working cuckoo clock at a thrift store. One of the most important parts was still there; the bird whistles. I took the front off of the clock housing, tied a Slinky Junior to the clock front and the clock housing. Yeah, that'll work.

Did you know that there are bellows that blow air into the whistles? I always guessed it was some kind of friction mechanism, like a cricket!

Can you see the clock on the set? Yeah, no. Too small. Important lesson here; make sure your prop fits the scale of your stage sets.

Sometimes (many times for me), you just have to throw out a design, and start over. All was not wasted for the original cuckoo clock, though. I used the bird whistles, and the wooden decorative piece for around the new cuckoo's door.

To get the right scale, I put scrap pieces of wood around the original clock, while on the stage. I measured the original clock's roof angle, using a T-Bevel tool, and transferred it to the new clock.

I used scrap material that we had in the set shop; 1/2-in. plywood for the front, and 1x6 pine boards.

Build the cuckoo clock housing, using the pictures as a guide. I used drywall screws and wood glue to fasten the pieces together. The shelf in the back will be put on later.

Carefully cut a 6-in. circle from the bottom portion of the front of the clock; this circle piece will be used as the back of the clock face. Cut an 8-in. circle from another piece of 1/2-in. plywood; this will be used for the actual clock face. Attach these two circle pieces together, as shown. This design allows the clock face to rest in the hole that was cut out.

I used the original cuckoo clock decoration on the new cuckoo clock. I didn't want to permanently attach it so I reused the holes from the nails that were originally used to attach it, and used wire from heavy duty paper clips to hold it in place. I also used paper clips to create a hinge for the door.

Cut a door out of 1/4 plywood. Make it large but not too large that a hinge cannot fit. My door is about 2-5/8-in. wide by 3-5/8-in. tall.

Cut a hole for the bird, slightly smaller than the door. My hole is about 1/8-in. smaller than the door, i.e., 2-1/2-in wide by 3-1/2-in. tall.

The bird moves in and out by a metal drawer slider. I already had a broken drawer slider from a dresser drawer; I knew I would use it for something, some day. Alternatively, you could create something out of a thin piece of wood.

If your metal drawer slider is too stiff, carefully break it apart, and remove the ball bearings. My drawer slide started out at 15 inches. To accommodate the wall thickness, the depth of the clock, and to limit how far the bird moves in and out, I shortened the slider to 10 inches. This let the bird come out to about 2-1/2 in. The drawer slider must protrude out of the back of the wall on which the clock is mounted. The slider is controlled by someone on the stage crew, from the back of the wall.

Since I didn't have a bird at the time, I needed a stand-in. I borrowed a small troll of my daughter's; she wasn't too pleased when she found out I had to screw it in to test it :-(

Add a shelf to the back of the clock, such that the top of the shelf is flush with the bottom of the door opening.

Attach the inner portion of the metal slider to the shelf with two screws. Lay the outer portion (with the bird attached) over the inner portion of the slider. Verify that it slides smoothly.

The bird will knock the door open. It seemed a little complicated, and error prone to add a mechanism to pull the door shut when the bird comes back, so we decided it was OK to let it stay open.

Since the slide mechanism was high above the floor, I made a pole to move the bird slider in and out. An alternative could be to use a ladder but the crew had several things going on, and best to keep them on the floor. The pole was made from a piece of 1-in. PVC pipe https://www.lowes.com/pd/Charlotte-Pipe-1-in-dia-x-10-ft-L-200-PSI-SDR-21-PVC-Pipe/1000080801, in which a wide hole was cut for the drawer slider to go through. The top of the slider (the bird side) was attached to the pipe with zip ties. The 1-in. PVC pipe was extended by using a 3/4-in. Hot-N-Cold potable water pipe, https://www.lowes.com/pd/Charlotte-Pipe-3-4-in-x-5-ft-100-PSI-CPVC-Hot-Cold-Pipe/1000199039, which was small enough to fit inside the 1-in. PVC pipe. I screwed the outer pipe into the inner pipe with small drywall screws. The larger pipe was needed to accommodate the drawer slider, and the narrower pipe was used for easier handling by the stage crew.

Thread string through the center of a miniature slinky (e.g., Slinky Junior), or other flexible spring. This string is for safety, and also limits the amount that the spring stretches.

Attach the spring and the string to one of the 1/2-in. pipe clamps. Attach the pipe clamp to the back of the clock face wooden circles with bolts through the front of the clock. These screws should be counter-sunk so that the screw heads are flush with the wood.

Put the housing on a table with the front flush with the end of the table. While holding the unattached end of the string onto the bottom of the back of the housing, gently let the wooden clock face circles hang off of the side of the table. Adjust the length of the string such that the spring stretches to the desired amount. Attach this end of the spring, and the string, to another 1/2-in. pipe clamp, and then attach the pipe clamp to the bottom of the back of the housing, as shown in the pictures.

Either paint a clock face, and hands, on the large wooden circle, or find a picture of a cuckoo clock face on the web. Scale the picture such that it is the same size as the larger wood circle (i.e., 8-in.). Print the picture, and cut it out. Glue the printed picture onto the larger piece of wood.

I created a mechanism to pop the clock face off, and automatically reset itself. The idea is to push a dowel through a tube that is mounted at an angle. A knob is attached to the ends of the dowel to limit its travel. The operator hits the knob/dowel and gravity causes it to slide backwards to its start position. Please use the pictures as a guide.

Mount the cuckoo clock on the wall, using the following steps.

• Cut a piece of plywood, in the shape of a triangle, at the same angle as the roof, the same size as inside the roof.
• Mount this piece of plywood to the wall where the clock is to be mounted.
• Hang the clock on this piece of plywood.
• Screw a couple of drywall screws through the clock roof and into this mounting plywood.

We had two members of the stage crew operate the exploding cuckoo clock. Since they were behind the wall, they used audio cues. The first stage crew member was responsible for blowing into two bird whistles (she was a flute player, so very competent). The second stage crew member was responsible for moving the bird out and in, while coordinating with the bird whistler. Then, the second stage crew member hit the exploding clock trigger knob as soon as the gun shot was heard. This was highly coordinated, and well rehearsed.

The "Crazy for You" exploding clock prop was a fun project, with several problems to solve. The prop must be safe, robust (i.e., always work), easy to operate, and it must be able to be reset easily for the next performance.

After a long search for a cuckoo clock, I found one. After taking it apart, and making it explode, I put it on the stage set wall, and realized it was too small get the attention of the audience.

Lessons learned:

• Allocate time for building prototypes, and iterating designs.
• It may be easier, and more robust, to control a prop by people than to automate it.
• Design props to fit the scale of the stage sets.

This project seemed harder to write up than to actually build; maybe I was in the zone, and having a lot of fun building it. I hope you have fun building it too. If you built an exploding cuckoo clock, please write about it in the comments; I'd love to hear about it.

Have fun,

Barry