Step 5: Materials and Tools

The materials required to build this Rubens' Tube are fairly inexpensive, most of which can be found on Amazon.com, or your local hardware store. Note that some of the recommended are not identical to the parts that I've used, they will however, serve the same, or superior function to what I've used. That being said, the materials you use, and the build process is extremely flexible and forgiving.

Building Materials:
Ventilation Ducting Amazon
Ducting used for HVAC, though any thin-walled metal pipe should work. My tube uses 4 inch ducting, I'd imagine success using anything from 2, to 6 inch material.
Amazon has a number of other products that should work. Something to consider is that if you use a large tube (in both length and diameter), you'll be dealing with more volume, which will result in taking more time to "prime" your tube. See step 13 for details.

Brackets x2 Amazon
These are brackets used for the supporting the ducting. Obviously the same size as the above ducting. (I used brackets which were an inch larger in diameter for buffering, however, in retrospect, I do not believe this is necessary)

Propane Amazon
This is the fuel source. Anything with a valve so you can turn it off and on safely should work.

Tubing Amazon
Nothing too insightful here, 1/4 inch inner diameter, or whatever fits your fuel source.

Hose T Connector Amazon
I used brass, but something like this would work fine.

Hose Splicers x2 Amazon
Used for fuel delivery. This will work much better than the small piece of copper tubing I used.

Latex Sheets Amazon
This will serve as our diaphragm. I used polyethylene sheeting, however, latex should perform much better as it's thinner and more pliable, but either will work and it just goes to demonstrate the flexibility of the build.

Scrap Wood

Tools and Supplies:
Drill Amazon
You'll also need a 1/4 inch bit and a bit between 1/16 and 1/32 Amazon

Hammer Amazon

Tape Measure Amazon

Knife or Scissors Amazon

Silicone Sealant Amazon

Epoxy Putty Amazon

Duct Tape Amazon

Masking Tape Amazon

Teflon Tape Amazon

Various hardware for attaching the brackets to your wooden base. Simple wood screws should work fine. A nail or similar may be needed for pre-drilling. And finally some hot water for working with the tubing.

<p>isn't it compression rather than condensation?</p><p>i thought condensation was something that happened on cold windows...</p>
<p>It is somewhat the same thing. To condense is to compress. like compressing water as a gas to water as a liquid on cold windows. Or to compress gas molecules together to form a higher density of gas (instead of turning into liquid).</p>
<p><strong>Very Nice</strong>... great the way you included the parts source too.</p><p>Thanks!</p>
<p>Awesome Instructable. Reminds me of old talking gas lamps that I can not find a reference for at the moment from the late 1700's and 1800's. I did find London still has gas lamps in place too. Anyhow... I did find this more modern system that seems really interesting also: http://www.instructables.com/id/Build-A-Plasma-Speaker/</p>
Can i do this with 1&quot; copper pipe with 2m length by using natural gas as fuel???
<p>If I had to guess, I would say that copper will conduct the waste heat too well, and limit you to short burn times. I would stay away from copper and opt for steel. Also, copper is really expensive.</p>
Great instructable! I wanted to make a smaller version for a class project. Could I make it with a 1&quot; dia copper tube and a small speaker? Also does it have to be really long? Could I make it less than 2 ft, or will the sound waves not form correctly? Thanks!
<p>My first prototype is 1&quot; metal tube with 2ft length and a small speaker. It works but doesn't seem quite good because the fire hardly react to the sound wave because the diaphragm are very small. I have improve it by change the small speaker to the normal speaker (with subwoofer), and enlarge the diaphragm by using funnel water and attached it to the tube. It works....but doesn't seem very nice. </p><p>Currently I am using 2&quot; tube (I want 3&quot; but couldn't find it anywhere) with 2ft ++ and a normal speaker (with subwoofer). It works perfectly fine.</p><p>Conclusion: Use bigger tube with enough length. You don't have to buy anything except the tuba (you have to drill it to make hole), but you can always borrow proper speaker from your friends to try it on your project. </p>
I've not tried this so I don't know for sure. My guess would be that it might be okay if you were working on a smaller scale with everything (including higher frequencies) The a small pip like that is going to have a drastically reduced internal volume, so I don't think you'd be able to expect the unit to produce very tall flames at all. I think it would be interesting to try, though.
<p>is it dangerous,,,if how can we prevent it !!<br> does it need high volume of sound??? any cause to speaker????</p>
<p>I did this for a physics project this year. It's a very fun project that I highly recommend trying. However, when you do, save yourself some grief and don't try to use PVC pipe. I thought it would be easier to work with, and I was very wrong. The first time I lit it, it went south so fast I had to use a hose to put it out. We tried to use foil tape to stop the melting, but it promptly burned off due to the heat. Metal HVAC duct works much better. </p>
I am doing this for my science project at school.
<p>I wander why you use propane and not natural gas.</p>
<p>Another warning, DON'T LET LIQUID PROPANE TOUCH YOU. I learned the hard way. The stuff boils at -66 degrees Fahrenheit when not in a cylinder, and it WILL give you a cryogenic burn, which immediately freezes the skin SOLID (it also causes a GIANT). Wear gloves designed to withstand the extreme cold. I was burned a few months, and it kept me from working for an entire week.</p>
Loved it. The video, the theme, the climactic and triumphant ending. Absolutely brilliant. I smell an Oscar!
Looks Crazy...
I saw this Ruben's Tube on an Show called FAQ, and I am from India you can also see the videos of Ruben's Tube from Faq on You Tube. And this Instrucatbles is just Awesome.
to pennyroyal69 , i think the problem is with the size of the holes in your ruben's tube !! Not the size ! You see larger holes mean lower pressur and the fire gets into the tube but make the holes smaller and te length of the flames will increase. Hope it workes :-) <br>
I have built a tube just like yours with a colleague, you can see it in action here: http://www.youtube.com/user/rubenstube101
Hey i just built one of these out of metal ducting but cant seem to get the pressure high enough. I was wondering what size your holes were and the diameter/fittings used in your fuel delivery system. It seems my regulator wont work without enough backpressure. any ideas or tips would be appreciated.
is it possible to do this rubens tube by using lpg...pls send me wetr it can b done by using lpg to my email id shahrukhextreme@gmail.com
Just remember, propane goes down (heavier than air) and it fills the tube first. This is important so you don't get a fuel-air mixture INSIDE the tube before you light it. It's the only reason it doesn't explode.
my rubens tube doesnt light up on the top, but instead lights up inside the tube, and i have to turn off the propane supply immediately to stop the fire. do u know why that happens, and for how long should i allow the propane to build up inside the tube?
Based on what frollard notes above, my guess would be that there's too much oxygen inside the tube. I may try the following: w/o the holes covered, allow the gas to run for a bit to push the O2 out of the tube, cover the holes to allow some pressure to build up, then uncover the holes and light the tube. <br><br>Timings will vary based on the volume of the tube and the gas output, and this is a potentially dangerous situation. Without knowing more specifics of your construction, I hesitate to say give the above a shot. But again, that's where I'd likely start to troubleshoot the issue. Please take every precaution possible.
The rubens tube in question is a 5 foot PVC tube, 2.5 inch in diameter, with 3/32 inch holes half an inch apart starting one foot from the beginning of the tube and ending one foot from the end of the tube. Instead of attaching the other end of he tube directly to a speaker, i taped a diaphragm onto it. The gas enters the tube through two tubes each drilled into the tube at the non-diaphragm end of the tube, placed on each side of the tube.<br><br>So far i have taped the holes and then allowed the propane to build up for two min then four min. At two min, the propane lit up inside the tube, but at four min, i did have flames on the top, but they were very small, and i had to ignite every hole individually. i havent tried allowing the propane to push out of the tube yet, as i ignite it as soon as i pull of the tape.
You need to cover most of the holes and fill the gas VERY slowly so it fills and displaces the lighter air -- as soon as you smell gas coming out you should be good. You never need to 'build up pressure' inside the tube. covering all the holes will just result in a fuel-air mixture and stressing the diaphragm. Imagine if you will that you have a tube filled with oil and you want to displace it with water...go slowly and all the oil should be pushed out before any water hits the holes -- same buoyancy/stratification effect here, just with different fluids.<br><br>Again, turn on gas long enough to displace air, so that only gas is coming out of the holes. Don't hurry the priming process because it will cause turbulence in the tube and that will MIX the fuel and air, a VERY dangerous combination. (read: explosive)<br><br>You describe the fuel entry as 'far from the diaphragm. It should be as evenly spaced as possible to make the gas input equal across the tube.
i am really thank full to you...........it helps me a lot....
If I will prefer to use one location for gas source (the other end of the tube) will it work? and what is the best material that I can use to ensure airtight seal?
I saw a video on youtube of a guy that did it like you want it. http://www.youtube.com/watch?v=HpovwbPGEoo<br>He mentions that he made holes with half inch increment (i think thats the difference between the first hole and the last one (?)) to get an even sized flame.. <br>
Using the either end of the tube for fuel delivery would probably produce an unevenly filled chamber. If you use just one source, it should be closer to the center of the tube, as suggested.<br />
I didn't do a great job cutting the tube to a good length, if i can cover the hole well will it matter?
Does anybody have some good resources on modelling a Rubens tube? I have a pretty good background in mathematics. I'd like to make a tube and use it for many hours at a time. I also do not want to get blown up. What have you all tried for getting good seals on the ends and where the gas goes in? Has anybody tried attaching fins to the tube or a fan to dissapate heat? My guess is that the diaphram would be less likely to break if it were exposed to less heat.
You know what would be neat? To separate a musical piece into its component instruments, and then play each instrument through a separate Ruben's tube. That way each tube will be showing the music cleanly. Of course, getting them all to start simultaneously might be an issue. So maybe a better idea would be to have live musicians play their music like they do on stage. It'd be a poor man's Trans Siberian Orchestra show!
Would it be possible to attach some sort of heat resistant nozzle to each hole, and do you think this would allow extended run times?
I suppose thta would be possible, though it may allow for pressure to equalize and thus degrade performance. The number one consideration with projects like this should always be safety. The with longer run times, it may be possible for the ducting to get so warm that it starts to melt attached tubing or the diaphragm. Using longer copper tubing to to feed gas into the unit would get around the first concern. Limiting heat to the diaphragm though would be slightly more tricky. I'm almost tempted to think that using a thick walled steel pipe would be a step in the right direction. Although it would retain the heat longer, it would also take more energy to raise the temperature of the surrounding material. These are just ideas off the top of my head, so take them with a grain of salt.
you could add 2 circular heat sinks used for capacitors to cool the ends by the ducting and then for the holes, somehow adding a graphite ring like an eye hook around each hole. Graphite has a very hight melting point.
Would this work with a curved tube? Like a circle or a like a horizontal wave? That would look really awesome if you could really perfect this.
That's an interesting question - though I don't think I can provide a solid answer. I'm trying to visualize what would occur, and my guess would be that something other than a straight segment would work, but the effect would be reduced, due to the wave being distorted by the curve in the tube. But then again, I'm thinking about how a stethoscope works - sound doesn't seem to have any trouble moving from one end to the other, regardless of how a doctor is holding it. Maybe someone with a better understanding of physics and acoustics can clarify?
I don't think a curved one would work well if at all because of all the waves bouncing off the walls. And it wouldn't be like a stethoscope because a stethoscope transports the waves through rubber, whereas this set up transports the waves through air thats in a tube. So they are very different concepts
good call.
Thanks so much for this! I made one for my Halloween party and everyone loved it. Don't know if the videos will load, but a friend recorded some with a cell phone.<br><br>I had trouble with the flame height at first, but giving enough time for the propane to build up helped. It also helped to raise the propane source higher than the tube - though far behind the flames, of course.<br><br>Strong, low piano notes or driving bass seemed to get the most effect, and higher notes had the least effect.<br><br>Managed to keep everyone entertained for 12 minutes!
Thanks so much for this! I made one for my Halloween party and everyone loved it. Don't know if the videos will load, but a friend recorded some with a cell phone.<br><br>I had trouble with the flame height at first, but giving enough time for the propane to build up helped. It also helped to raise the propane source higher than the tube - though far behind the flames, of course.<br><br>Strong, low piano notes or driving bass seemed to get the most effect, and higher notes had the least effect.<br><br>Managed to keep everyone From 4 to 65 entertained for 12 minutes!
We tried constructing one of these (almost exactly as described) but couldn't get the flames to hold. It seems that the gas pressure from the standard propane + nozzle kit simply isn't high enough. Everything is fully sealed, and I tried doing it with very few holes (maybe ten) and it still couldn't keep them all ignited, let alone steady. Any suggestions?
It's hard to say exactly what's occurring to cause the problem you're experiencing. Though my first guess is that there's not enough pressure being built up before attempting ignition. I make a note of this on <a href="http://www.instructables.com/id/The-Rubens--Tube%3a-Soundwaves-in-Fire!/step13/Using-your-Rubens-Tube/" rel="nofollow">step 13</a> - I suggest looking over it again, paying particular attention to parts two and three.<br> <br> Let me know if this doesn't resolve the issue - I'd be glad to troubleshoot with you in attempts to get your tube functioning as it should.<br>
Were your experimental measurements similar to your theoretical measurements? I ask this because the speed of sound is 340 m/s in air but the sound waves are being created in a medium that is composed of propane. The speed of sound in propane is ~247 m/s. This would significantly change the theoretical wavelength for an arbitrary frequency.
I recall things being pretty close -- though now that you mention it, considering the peaks and troughs are fairly subtle, particularly at the longer wavelengths where the discrepancies would be more noticeable, I very well may have been off in my measurements. There's also the possibility of an air/propane mixture in the tube, which would put the density of the medium somewhere between propane and air.<br> <br> It's been three years (to the day!) since this Instructable was published, and unfortunately, I no longer have the device, so am unable to go back and check for confirmation, one way or the other. However, your observation's very astute, and I've started to do some research on the issue, though have found conflicting reports. As soon as I've got things figured out one way or another, I'll update the Instructable to reflect that - though until then I'll put a disclaimer on the top of this page.<br>
We&nbsp;have thoroughly enjoyed this project!&nbsp;&nbsp;I have found some things work and others need improvement. We used a thicker pipe than we wanted. We found it in the fencing area of our local hardware store. It was a fence post. I recommend using the thinest pipe you can find. We drilled our holes 1/2 inches apart. I recommend drilling them 3/4 in to 1 inch apart. We sealed every other hole up. One end can be sealed with a pvc pipe-cap.&nbsp;Make sure to use Teflon tape&nbsp;on the pipe before sliding the cap onto your&nbsp;pipe.&nbsp;It can also serve as the fuel source by drilling a hole for the propane fitting. The other end can be sealed with any latex rubber you can find and some ordinary rubber bands. It is better to make sure to leave 6 to 10 inches on both sides to not allow your ends to get to hot. We used 7/64 drill bits. A few might break. I recommend using a smaller drill bit if possible. The 7/64 will work though.<br /> sci5 is our physics teacher.<br /> sm and bj the hallmonitor
I'm thrilled to find out that the project's being used in the classroom. Good luck, and keep us updated. <br />
Thanks for all the info you have put up.&nbsp; It helped me a lot with my tube.&nbsp; My only problem was I put the propane injector and speaker at opposite ends.&nbsp; Making the gas not evenly disperse throughout the tube.&nbsp; The best way to install your injector is in the middle or to have multiple injectors.<br /> <br /> JaketheSnake

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