Growing Wheels




The idea behind this project was inspired from a trip I took to Moose Factory in the March of 2015. It was cold, about -30 Celsius outside the bus as we pulled into the small town of Cochrane in Northern Ontario. The bus wheel had been caked in salty slush from the road, and much to my surprise, there were icicles growing outward, radially, from the the wheel hub nuts.

It wasn't until the fall of 2015, riding another bus, this time to Boston, that I thought I should make a system that uses that centrifugal phenomenon to grow wheels. Having been captivated by John Edmark's Blooms project, I had the idea to light the spinning wheel with a strobe, so that all growth would be revealed to the observer.

The project has taken three iterations to date. The first was a 3D Printed wheel (shown in orange) and central hub on a pencil axle, connected to a small 12V DC motor. A glue gun was used to apply molten glue. It was basically a cotton candy machine, without the delicious benefit of working in sugar. It served the purpose of proving the concept.

The next system was a step up in complexity. I used a Shopbot to mill a wooden disk, rolled a steel strip and riveted it into a circle, then glued that to the wooden disk. A hand lathed aluminum axle + hub was mounted to the disk using a shaft collar, and mounted to a block of oak using an industrial ball bearing pillow block. The other end of the axle was connected to a drill chuck, and spun the whole wheel system. A glue gun was disassembled and modified to accept several naked crayons forced through an aluminum tube with a wooden dowel. This squirting melt hit the hub and created stalactites, shown above in pink and green.

In this Instructable, I will share the step by step production of a much more robust system, that includes a wheel and axle for stalactite growth; a pillow block and gear motor mounted to a housing unit; an electrical circuit with motor controller and synced strobe light; a heated wax hopper with needle valve, digital temperature control, and applicator nozzle.

The result of this third iteration is....

At the end of this instructable I have included supplemental steps outlining how you might do the project more simply, by including some of the elements of my second iteration of the project.

Step 1: Make a Crayon Melter

Glue guns convert easily into crayon melters. For one thing, crayons and glue sticks (the small kind ~3/8") are almost the exact same radius. In some models of glue guns this fit is perfect. others the crayons are a little tight. For this project, I removed the nozzle of the glue gun to make use of the heating element and tip. It was then press fit into an aluminum tube, rewired, and fit with a ram-rod made of wood doweling.

Step 2: Lathe a Hub on a Manual Metal Lathe

This might not be realistic for everyone, so here are a few alternatives:

Step 3: Skin the Crayons

The best way to do this is to stick them in the freezer for a few hours first. Then you can push about 60% of the crayons out of their jackets by pressing the tip to the table and holding the sleeve. Some colours are easier than other... Go figure.

Step 4: Cut a Ring

I found using the horizontal bandsaw to cut 1/8" acrylic tubing pretty effective at this. The exact product I bought from McMaster Carr was Impact-Resistant Polycarbonate Round Tub 8" OD, 7-3/4" ID, Clear. It is not cheap. ~$40/ft.The vice does pinch the ring into an oval, but it seems still to cut square and bounces right back to its imperfect self after coming off the saw. The grooved wheel in the next step keeps the ring circular and mounts to the axle.

Step 5: Shopbot Route a Circle With a Groove

I have included an image of the Fusion 360 file that I used with the Shopbot to carve this wheel. I have also included the .sbp.

Step 6: Tap a Shaft Collar

Tap a shaft collar to fit around the lathed axle. This will keep the disk from slipping by using a set screw to hold it in place.

Step 7: Bearing Assembly

This will help keep the axle aligned with the motor shaft to transmit power to the wheel.

Step 8: Mount to Block and Spin With Drill. Apply Wax Liberally.

Step 9: Alternative Wax Applicator

Use a heat gun to melt a few crayons at a time in a coffee cup. Careful not to start a fire. Cups are flammable. So are crayons. Wearing eye protection, pour the molten crayon from the cup in a steady stream in front of the spinning wheel. Blow the stream into the axle to begin stalactite growth in a simulated gravitational environment. Enjoy radial growth of stalactites!

Step 10: Check in Later for a More Advanced Version

This project can be done with an automated applicator, heated reservoir, and strobe light to be able to actually see the growth of the stalactites as it happens. Stay tuned for further images, instructions and videos from this project. Much Love Makers.



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    3 Discussions


    2 years ago

    This is amazing! Did you find an optimal speed for the wheel to spin?

    1 reply

    Reply 2 years ago

    Thanks for the enthusiastic comments! I haven't yet experimented with the system enough to know what optimal would mean. On the one hand, for filming the growth process (video still to come) the spin rate should roughly match the frame rate of the camera to capture the growth as if it were not spinning at all. On the other hand, the speed will effect how long the stalactites grow and the rate of growth. I will be investigating the related rates over the coming weeks.


    2 years ago

    Wow, amazing!