Assuming you've already gone over the safety notes, the first step in using the Rubens' tube is to "prime" the tube.



First - Attach the fuel source. Again, make sure there's a safe length of hose between the propane tank and the tube itself.



Second - We're going to want to create some positive pressure inside the Rubens' Tube. Because the flow of propane is fairly slow, and there's a lot of volume within the tube, we need to seal it up temporarily. To do this, use a strip of masking tape to cover all the holes on top of the ducting. Then turn on the gas.

Wait about two minutes, by this time enough propane should be in the tube to create a decent pressure differential. Depending upon the size of your tube, and the pressure of your fuel source, it may necessary to wait a greater, or lesser time.



Third - Remove the tape covering the holes. Then, using a long match or fireplace lighter, try lighting the gas by one of the holes. Assuming there's enough pressure, each hole should ignite down the tube. However, it may be necessary to light the tube in several places.

If the flame is very small, it may be indicative of lack of pressure within the tube, so you'll want to wait a bit longer the next time around before removing the tape.



The tube's ready for prime time when each flame is roughly an inch in height.



Fourth - Introduce an audio source near the diaphragm. You should be able to excite the flames by lightly tapping on the diaphragm, or even snapping next to it. However, for the most fun, and scientific pursuit, you'll want to use a speaker. See step 5 for notes on the sound source. Refer to the safety notes for turning it off.



You should be able to literally see the wavelengths of various audio sources. Head back and take another look at steps 2, and 3 to get a better understanding of exactly what's happening. As entertaining as dancing fire can be, there's a lot of science behind it too.



Notes

1 - I'd imagine one could complete this project in no more than an afternoon assuming all the supplies were on hand. I obviously worked with a bit of trial and error, so it took me some extra time.



2 - My average run times range from about 5-10 minutes. I'd imagine one could run the tube for longer than that, however, I'd err on the side of safety and keep the times limited.



3 - Keep an eye on the diaphragm. It's completely possible that the diaphragm may exhibit signs of wear over time. Although this has not yet been an issue for me, I could foresee possible diaphragm maintenance being needed one day.



And finally - Be safe, learn, and have fun.

