Instructables
Picture of Rubens Tube Yule Log
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Maybe you've seen a Rubens tube, before? Well I'm sure you haven't seen one this festive. All it takes is some wood, some hardware you can pick up in any neighborhood, and a few common tools.



I'd like to extend a special thank you to Oscar for all of his help and photography on this project.
 
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Step 1: Gather Materials

You're going to need:
  • An aluminum tube around 2" in diameter (pvc will work, but you'll have to cover the top in foil tape, and check to make sure it doesn't overheat while on)
  • 2 clamps for 2 1/4" chain link fence (these hold the fence to the upright poles)
  • A log of some description
  • Screws
  • 2-3" PVC end cap
  • Masking tape
  • A ruler or measuring tape
  • 2 part epoxy putty
  • A sheet of latex, rubber, or plastic that can withstand some high temps (test it in the oven on its lowest setting, if you notice strange things or bad smells after ten minutes, you need another material)
  • Zip ties
  • "L" brackets
  • A butane tank
  • A butane tank regulator
  • >3 ft of 3/8" polyurethane tubing
  • 3/8" barb adapter
  • A stick lighter
  • A small speaker
  • Duct tape
  • A drill
  • 1/16" Drill Bit
  • A step drill
  • A punch

Step 2: Understanding the Rubens Tube

Picture of Understanding the Rubens Tube
The Rubens Tube is a time honored physics demonstration, seen across this great land since at least last Tuesday. In essence it demonstrates how sound waves bouncing around in a tube create high and low pressure zones which affect the flow of gas through it.

For some really well researched and detailed descriptions you can visit:
http://en.wikipedia.org/wiki/Rubens_tube
http://www.instructables.com/id/Wiimote-Rubens-Tube%3a-Control-Fire-With-Sound!-And/?ALLSTEPS
http://www.instructables.com/id/The-Rubens_-Tube%3a-Soundwaves-in-Fire!/?ALLSTEPS

But for now, we're going to focus on constructing this festive widget.

Step 3: Mark & Drill

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You'll need to get 1/16" holes in the top of your tube spaced 1/2" apart. I left about three inches of room between the holes and the end of the tube so that the components on either end wouldn't heat up.

Tape your tube down to a flat surface, and put a strip of masking tape across the top. Mark spots for holes along the tape 1/2" apart. Take your punch, and put a little divot in the center of each mark. Carefully drill each hole, placing the 1/16" drill bit square into the divot.

Step 4: Add brackets and clamp your log

Take your Yule Log in hand and admire it. Imagine it with fire shooting out every which way. You'll want to put the Rubens tube on in a way which will be both convenient and pleasing. Just slip the chain link fence clamps over the tube and use wood screws to attach the assembly to the log.

Also, put an "L" bracket on the side of the log to accommodate the speaker.

Step 5: PVC endcap

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You need a hole in your PVC end cap to facilitate your barb adapter. I clamped the endcap, marked the center, and hit it with the punch. After taking out most of the material in the hole with a regular twist drill (be careful, PVC has a nasty habit of grabbing hold of drills and being mean to them) I enlarged the hole to nearly the size of my fitting with a step drill. Your fitting may vary, so check your measurements, but mine was 9/16" across. After your hole is the right size, you can simply screw your fitting into the hole with a wrench.

Step 6: Epoxy end to end

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Moosh a gumball sized blob of epoxy putty over and over until the color smooths out. After everything's homogenized, roll it into a snake, and lay it in the inner corner of your PVC endcap. If you've played your cards right, it should fit all the way around, and pressing it onto the end of the tube will create a nice, even seal. If you didn't play your cards right, like me, you'll have to seal things again with a bead of silicone caulk around the lip of the endcap.

Step 7: Speaker goes adjacent {With Important Safety Note}

I initially made the mistake of taping the speaker directly on to the other end of the pipe. Do Not Do!

I replaced this fairly poor concept with a latex membrane I found (rubber, plastic, or another flexy material will probably do well.) I just popped on the end right before the speaker with some zip ties. The speaker is just duct taped to the "L" bracket.

Step 8: Void some warranties

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Clamp down your gas regulator and drill out its outlet aperture with a drill bit. It doesn't have to be all kinds of huge, just wide enough to allow for a lot of gas flow. About 1/16" should do. Attach this to the gas bottle, and in turn to your tubing.

Step 9: Now, add tubing to log, and ignite.

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YOU ARE NOW PLAYING WITH FIRE. I DON'T RECOMMEND ANYONE ACTUALLY TRYING THIS FOR THE SAKE THAT YOU COULD 'SPLODE AT ANY TIME. IF YOU DO CONSTRUCT ONE OF THESE DEVICES, BE EXTREMELY CAUTIOUS WHERE YOU SET IT UP, HOW YOU USE IT, AND BE EXTREMELY MINDFUL OF YOUR SURROUNDINGS. LIGHT IT WITH A STICK LIGHTER. HAVE A FIRE EXTINGUISHER HANDY.

It's time to plug in the speakers, pop the gas line into the tube, turn on the gas, and let 'er rip. I found that it worked best at high volume, with songs that had a few, strong instruments, as opposed to more mixed orchestral music. I also found that the best results came from having just a small stream of gas moving through the tube. Feel free to play around and tweak. Using a tone generator, like the one found in Audacity can be really fun.

Happy Making.
WhiteTyrone10 months ago
You mention that taping the speaker directly to the pipe was a mistake, but didn't explain why this was a bad idea. I'm temped to try it now that I know something exciting will happen! Then again, you wrote "Do Not Do!" in bold, so I am hopeful you might be able to tell me what the result was.
Thanks!
Aron3132 years ago
worst song tho!
indrkmt3 years ago
how long is the pipe you used??
replay please
If you were to keep the tuve on a log in the freplace you could always paint it a color tomatch the surroundings of the hose.
Astinsan6 years ago
Neat idea but I wanted to add some safety information for the people that may not think about it. I think that the tubing and propane tank may not be a good idea. Vinyl tubing can be a static magnet. I also don't think you should use this setup in a house. A leak of propane will hug the ground. You could be unintentionally filling the house with propane and not know till its to late. Natural gas is lighter which is why you smell leaks of it when they happen (they add the smell though). Using a cheap 30oz propane tank is also a bad idea. Newer LP tanks have fall over shut off valves. This will prevent liquid propane from flowing out. Liquid propane on vinyl tubing will most likely cause a leak. Liquid propane can and most likely will burn your skin. How to fix the issues.. I was thinking that using compressed air to blow on another ignited item. Should work for gas fireplaces and wood. Have a good Christmas. Astinsan
That is some good safety info but you also have to know that propane(especiall if you're in a weel vented area) dissipates into the air. But on the otherhand it may not,dependibg in some conditions such as bad ventilation,@but you can always check or leaks with some soapy water.
you could maybe take the clear hose and poke some holes in that and run it down the length of the pipe to get more gas out of it and to make it and even distribution. i am always thinking (it's because im a gas lamp freak) you could make a small one about a foot long or so and make and outdoor or maybe indoor gas lamp fixture. alls yooz gots to dooz is make a metal safety sheet behind it and not too far above it and mount it on something where you can still have the hose run down to your tank on the table or floor. i think it would be pretty cool. you could (just like in the instructable) make a little fireplace for it!
:D
Kiteman3 years ago
Apparently, the videos have been deleted...?
kelsey-01905 years ago
can anyone help me on the ruben's tube thingy in doing this for science fair !!!!! plase anyone just write back if they can help
LOL! the wave bar in winamp FOR PIROMANIACS!
Steve17766 years ago
Very nice. Why not go down to the hardware store and get some metal gas pipe that is used to bring the gas into the house? It would be harder to drill (probably need a drill press) but it would not melt. It would be smaller, maybe drilling larger holes would correct for the size. Use copper tubing from the tank to the tube. Use ceramic logs. That should be safe.
bofthem (author)  Steve17766 years ago
I did use metal pipe for the tube. The small gas line pipe you can pick up from the hardware store is expensive, and too small to really resonate for the main tube. I also wouldn't use it for getting the gas from the bottle into the Rubens tube, as it's difficult to work with and cant' be adjusted easily. For safety, it'd just be easiest to get a flexible gas line meant for an outdoor grill, and get fittings to adapt it for a small gas bottle. I found ceramic logs at Home Depot at $120 a set. I just wasn't willing to pay that price for the added safety. If I had infinite time to play with this project, I probably would have sculpted a log out of clay, and let it harden. It could be custom shaped to the tube and be flame resistant. I'm not saying your suggestions aren't well taken, and they are great. I just was willing to sacrifice safety for ease of construction and price.
WingDings6 years ago
Yay! Good call on the Conchords tune!
tradergordo6 years ago
You should not surround this with combustibles (like real wood logs!!) or you are just asking for trouble.
bofthem (author)  tradergordo6 years ago
Yeah, it'd be completely unsafe... if it weren't in a fireplace.
Its not all that safe even in a fireplace because of the nearby gas, not to mention all the parts that aren't intended to burn but could if your combustibles ignited. And then you have the people with natural gas or even electric fireplaces that might try this in there, in which case burning a log could burn their house down.
bofthem (author)  tradergordo6 years ago
I agree that there are dangerous elements presented here. I have recommended that people not replicate this project. I have also advised fire safety, caution and extinguishers. There is a chance this device, like any combustible-fueled contraption, could cause some kind of cataclysm. I thoroughly tested the propane setup, and found that it was not capable of producing a flame that reached outside of a 1' radius. Given this, I felt that this setup, even if it experienced some kind of full spread, would not have the kind of combustive force to exceed the footprint of my fireplace, and any average home fireplace. Additionally, this scenario only seems feasible if I lost my mind and left this burning unattended at some point. I understand where you are coming from with the gas fireplace and electric fireplace concept, but have not specifically recommended them. They are not safe places for an open flame from any source other than their own mechanisms. I cannot picture someone mistaking this project, thinking it's meant for a gas or electric fireplace. It's meant to be put in a safe place for an open flame.
I have recommended that people not replicate this project.'
You do know that discouraging admonishment is the fastest way to get DIY people to do something, right?
It also reserves the "I told you so" rights of the discouraging party :)
el kabong6 years ago
This is a great idea. I'd really like to make this as a gift. Two questions, though: What do you use for a speaker? I have zero electronics ability/experience- is there a real simple solution for a mono speaker powerful enough to move some air through this tube? Also, does the music sound good through the little speaker and tube? I was thinking that if I figure out a speaker option I could use a headphone-splitter to send the sound out to the nice sounding stereo from the mp3 player or laptop or whatever...
brad el kabong6 years ago
A good cheap source of an amplified speaker is a cheap set of computer speakers (that you plug into the wall, not "unpowered"). You can find them for $15-20 at your local computer/electronics stores. With them unplugged, carefully pull them apart (you'll need screwdrivers). You'll find a circuit board and, most likely, two wires running from that board to the center of the speaker. Take the whole setup and remove it and bingo! Cheap, bare, amplified speaker.
bofthem (author)  el kabong6 years ago
I went with an amplified speaker (one you have to plug into a wall outlet.) It worked great, and the sound was fine, given there was another tweeter and a woofer in the set. Nearly any speaker will do if you can give it enough volume, but this requires external power, so you could put it through an external amp.
suggsugg6 years ago
sweet music, flight of the conchords rocks. "Brown paper white paper stick 'em together with the tape, the tape of love". I can't wait until the new season
(removed by author or community request)
bofthem (author)  DELETED_dannydutton6 years ago
Yeah, I'd set this up somewhere safer. The driveway is always an option, if it doesn't have standing oil or anything on it. It's a bit less effective outside because of draft. You could also consider a fire pit or chimnea.
Kiteman6 years ago
Nice - I've added it to the Christmas Competition group.
bofthem (author)  Kiteman6 years ago
Thanks. I don't think I'll be seeing a victory from this one, mostly due to the fact that I'm an Instructables employee. I don't see what a little cronyism could hurt.
Kiteman bofthem6 years ago
Ah, I forgot that rule. Still, it would have been worth entering if you just an ordinary punter.
Pyrowuzzup6 years ago
this is a great idea. correct me if im wrong but wouldnt a one way valve help avoid the occasional explosion? or is that fairly unlikely?
bofthem (author)  Pyrowuzzup6 years ago
It'd be prudent. The only chance of 'splosion would come in if air somehow invaded the tube. The flames rising from the tube pretty much eat all the available oxygen, and prevent any kind of combustion within the tube, and especially the gas line. Something would have to happen to cause air to back into the line and ignite. The chances are really far out, but it's worth considering.
Great instructable! Love it! I had the same idea but was to lazy to give it a try. I was thinking it would be awesome for an outdoor fire pit.
OOOOHHHH! Good idea. You would need a round tube though.
bofthem (author)  Doctor What6 years ago
the wave effect probably wouldn't be as pronounced, though. The straight tube provides an ideal environment for sound waves to stack up on one another, there'd probably be a good bit of interference in something with some curve to it. It's worth a shot.
very nice! my fireplace looks like yours, except for the electric wires and stuff. cool pictures!
nanor113956 years ago
good job