Disco Death Ray

Wielding the power to melt glass or instantly ignite most day to day materials can be intoxicating pretty fun. With a little math, a lot of patience, and 5,800  1cm pieces of mirror, this build requires welding glasses just to look at the 1-2cm focal point. With an idea rumored to date back to Archimedes, this more portable parabolic project is perfect for your home burning needs. Unfortunately, this setup seems to have burnt itself to death at some point, though that makes room for version two, which will reportedly bump the mirror count to 32,000 or so.

There are plenty of other ways to make a death ray out there as well, including using lasers or lenses. Think you have a better tool of destruction? Be sure to tell us about it.

49 thoughts on “Disco Death Ray

  1. good grief, man! I appreciate the effort this guy spent gluing all those mirrors, but all he had to do was get a wooden hoop, soak it in water and bend it to the outer shape you wanted. When it dries, attach a Mylar sheet to it, seal well, and seal the back. Apply a vacuum to the assembly and the Mylar will form a smooth curve. I’m willing to bet it will reflect light better too, but I suppose I am missing the point of using the massive amount of mirrors. I did solder my own LED matrix using 1536 LEDs after all…

    if you can’t find a regular sheet of mylar, get a solar blanket. same stuff.

  2. Maybe it would be easier to polish the dish itself rather than glue down thousands of mirrors?

    My kids and I have been having fun with the 11″-square fresnel lens I got from from Edmund Scientific :^)

  3. Alex: i was thinking the same thing, but then i just lost interest. Those idiots over at mythbusters do everything so half arsed that i stopped watching long ago.

    remember kids the mythbusters couldn’t do this so it must be a fake.

  4. IT’s easier to do with a large old dish, some silver paint, clear paint, sandpaper and polish.

    Paint it silver, then clear, then wetsand with 800 grit, 1000 grit and then 2000 grit. Polish with car rubbing compound.

    DO this to a 10′ old aluminum dish and you get a killer solar deathray with a focal point hot enough to melt salt.

  5. I second the MythBusters comment. I’m always surprised that something is deemed impossible if two people with communications degrees cannot manufacture it on a $50 budget in a day.

    I too stopped watching long ago.

  6. First… Does anyone think it’s kinda dumb he’s not wearing protective gloves in that video???

    Second… I think it’s kinda funny that MythBusters failed at this not just once, but twice.. the episode featuring Obama they went back and tried it again…. Someone should seriously send them this I wanna see them burn a boat

  7. Don’t they make telescopes like this to avoid having to use huge pieces of glass? I wonder if it would be possible to get any (presumably poor quality) images from a mirror like this in a telescope configuration with a secondary and an eyepiece.

  8. Just imagine an entire superbowl stadium, filled to capacity – except on “FREE Blackeyed peas CD day”.

    Imagine a bright sunny day and a retracted roof in Arlington, Texas.

    Imagine a lame halftime superbowl show spiced up with a short instructional video on how to aim and use a CD as a signal mirror…

  9. Mythbusters are not scientists but special effects guys.

    They failed miserably when trying to cook a chicken on a low power microwave site.

    “If” they had done the same experiment on the output of a kilowatt level waveguide on an active military radar transmitter, that chicken would’ve been ready to have for lunch!

  10. @Matthew
    As pointed out before, if you use a ring and a vacuum with reflective material (mylar) you could feasibly change the diameter of the ring…. which should change focal length if vacuum pulls the same.

  11. lol @ the people dissing mythbusters.

    Its a kids science show, dont expect pure science in a show that has to keep people entertained and the show simple in a limited budget and timeframe.

    Aim, hypothesis, procedure, results, conslusion. Don’t expect anything else.

  12. @spork
    All you need to do to change the focal length is vary the vacuum. No need to vary the hoop.

    @all suggesting paint etc.
    Efficiency will be no where near that of mylar or glass mirror (particularly first surface mirror).

    The key point to what mythbusters was trying to accomplish was using the tools and technology of the period. You don’t really think they would have failed using current tech. do you?

    Also, if you look in the video at 22 seconds in, you can see he’s using second surface surface mirrors. This same project using first surface mirrors would have dramatically better results. Looks like those little mirror squares you get at the craft store. Then again most people couldn’t make it for 90$ with first surface mirrors. Alas, kudos to the maker. I stare at rolls and rolls of mylar mirror material, and large first surface mirrors all day at work and have no motivation to do this. Of course, once you hold a 3 ft by 4 ft fresnel lense in the air and watch concrete pop away like popcorn and burn through the side of steel buckets or melt extruded aluminum it just seems like way too much work. Lol

  13. @all: 2 reasons why mythbusters failed.

    1.What mythbusters were trying to do was see if in Archimedes day this could be done. What they tried was 2 different ways to ignite a moving target on water. Not to ignite a chunk of dry wood at 2 feet.

    2.If they had been using modern tech they would have succeeded.

    I would have made the light from 50 of these run into another parabolic reflector, then into a fresnel lens, then into an optical fiber that could be fed into a gun frame. Not very mobile mind you but effective.

  14. I can’t think of a better fate for many disco balls – good build (and the claims of obliteration are pretty good too). Wouldn’t it be a “Death Focal Point” rather than death ray, though?

  15. I agree w/ Rob Wentworth’s suggestion of using aluminum foil on the dish. What’s even easier is to put the foil on a wok & make it portable also. I use my wok w/ a PC mic as a parabolic sound dish. All I need to do is to put the al foil on it and replace the mic w/ whatever I want to burn. Just make sure I clean up the wok before my wife kills me. ;-) After all, this is just basic high school physics. The energy at the focal point is proportion to to the square of the dish diameter to focal area dia. ratio. So like they say, the bigger the better.

    I think the whole point of this “hack” is the teenager is utilizing what he learnt and apply it other than just sitting in front of the TV/PC playing mindless games all day. After all, this is how all great minds begin. Good job kid!

  16. @Mojoe many mirrors are just a bit of cheap paint-stripper away from being first-surface.

    I’ve been wanting to do this for some time now as a solar energy collector. I’m not set up to make a Stirling engine, but I have a few small IC engines that could be converted to passable steam-engines. Just one of hundreds of things I’ll probably never get around to…

  17. Awesome work. I cant help but think he succeeded where mythbusters and MIT failed. But i suppose we need to be fair to MIT and Mythbusters, they were trying to aim the focal point further out but still.

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