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Weekend Workshop: Build a fire-spewing Rubens’ Tube music visualizer for under $150

Need something to keep you busy this weekend? Look no further. The Weekend Workshop is our weekly column where we showcase a badass DIY project that you can complete with minimal skills and expertise. We’ve dug through all the online tutorials on the web, and gone the extra mile to pinpoint projects that are equal parts easy, affordable, and fun. So put on your work pants, grab your tool belt, and head to the garage — it’s time to start building!

If you’ve never seen a Rubens’ Tube before, you’re in for a treat. In a nutshell, this crazy contraption is basically a waveform visualizer that uses fire to display the shape of sound — and it’s surprisingly simple to build. The whole apparatus is basically just a closed tube with a few holes drilled in it and some propane pumped through it. Light the jets, put a speaker on one end, and the flames will magically start to pulse along with the music.

Here’s how it works: As sound moves through the gas, the waves create areas of high pressure and low pressure form at fixed points along the tube. This forces the propane gas to be expelled from the holes more quickly in some zones (generating a taller flame) and more slowly in others (creating a shorter flame) This effectively allows you to visualize the standing wave that’s created inside the tube.

When you play a constant tone of, say 440 Hz (the musical note A), the flames will form a perfect sine wave. Adjusting the frequency of this tone will alter the shape of the wave accordingly, and playing a full song will cause the flames to dance and pulse with the music. This pyrotechnic visualization is absolutely mesmerizing to watch, and is guaranteed to be a hit at your next backyard party.

*Note: Working with fire and propane is a potentially dangerous activity. Digital Trends accepts no responsibility for injuries sustained while performing these activities, and recommends the use of proper safety equipment during all stages of the process.

What you’ll need

Tools

  • Electric drill
  • Drill bits: 1/2 inch and 1/8 inch
  • Tape measure
  • Duct tape
  • Masking tape
  • Scissors
  • Pliers
  • Permanent marker
  • Metal file

Materials

  • 5 feet of metal duct pipe (3-inch diameter)
  • Plastic or metal end cap (3-inch diameter)
  • 2 brass barb MIP adapters, (3/8 inch x 1/4 inch)
  • 1 plastic barb tee adaptor (3/8 x 3/8 x 3/8 inch)
  • 2 rubber o-rings (1/2-inch diameter)
  • 2 washers (1/2-inch inner diameter)
  • 10 feet of latex hose (3/8-inch outer diameter, 1/4 inch inner diameter 
  • 1 latex balloon (large)
  • Old computer speakers (Or new, whatever. I find that Goodwill typically has a good selection.)
  • Propane tank (20 gallon)
  • Propane tank regulator w/ 3/8 inch barbed output
  • Safety glasses

Next page: Let’s do this!

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