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Thread: Lasers for stage use

  1. #11
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    well the beam will always look thick in fog..

  2. #12
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    You'll probably want a hazer running all the time, and then use a fog machine to augment the effect right before you switch the laser on.

    You can use the fog for dramatic effect too, to help introduce the act... Prop rising out of the fog - that sort of thing. Then the fog stays around long enough to make the beams even more visible than they would be with haze alone.

    Beam expander is nothing more than a pair of lenses. You could probably assemble one yourself and save a lot of cash. Still going to be rather large though - gonna be tricky to get it to fit in the palm of your hand. (Will need high refractive index lenses.)

    Adam

  3. #13
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    Right, first stop, mister/fog shop... think I'll see what my current laser looks like under those conditions, then I'll go down the beam expander route if that's not visible enough for my use.

    Thanks ever so much for your help guys, I'll put on a vid of the finished act when it's done, probably about 12 years from now.... lol

    Thanks again,

    Rich

  4. #14
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    once you have your hazer, you could experiment with what other effects you could get away with... some molefay pointed at the audience with some haze would probably blind people enough to give you time to do lots of magician type things.

    Just saying, if your buying a hazer, you should get full use out of it...

  5. #15
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    Personally I'd think it very risky to use more than 5mw albeit you will need plenty of haze to see it clearly.

    A pointer puts out a single concentrated beam and from 50mw even a glance could permanently damage your eye sight or that of your audience. Making it fat beam will help, but even then your potentially playing with fire. I see that companies selling fat beams such as the Chauvet Scorpion projector with a 14mm beam in the US still only seem to use 10mw max.

    I'd consider a < 5mw round barrelled key ring green laser as its far easier to conceal than a pointer being smaller and at that power is likely to be much safer unless you deliberately stare down it. My friend had one of these and they're literally about 1/2 inch in diameter and 2-3 inches long. Unfortunately he bought his on holiday in Spain, so I can't give you a source.

    All you will need to do is increase the haze / fog as the beam power is decreased. They're cheap so you could buy and try one.

  6. #16
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    Quote Originally Posted by RGBLaserFan View Post
    All you will need to do is increase the haze / fog as the beam power is decreased
    Excellent.. I'll get loads of cash back when I sell off the class 4's and replace them with pointers and bigger fogger...

  7. #17
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    Keep in mind that the audience isnt going to be hanging above the act, so they have to be able to clerly see the beam from like a 90 degree angle. I know dealextreme sells little green keychain pointers that are pretty small.

  8. #18
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    Quote Originally Posted by p1t8ull View Post
    Excellent.. I'll get loads of cash back when I sell off the class 4's and replace them with pointers and bigger fogger...
    Point taken Pitbull but I was just trying to steer him towards safety - you aren't doing an act with a single concentrated pencil beam 3 feet from your face and playing with mirrors its easy to accidentally direct the beam straight into your eyes. He's going to have to try experiments with visibility.

    Only point I was making is that anything over 5mw is going to be very risky from a safety point of view. Below 5mw there's still a risk from that distance but its lower. A beam collimator may allow him to raise power a little, but by how much? Its Russian Roulette unless someone is kind enough to do a safety calculation involving beam diameter vs power so as to establish the power to buy to give the equivolent radiation of Class 2 or Class 3R on a collimated beam, but even with Class 3R there are risks albeit low.

    Would you really recommend the guy to wave around a 50mw Class 3B pencil beam just 2-3 feet from his eyes?

    Edit: only other answer I could think of would be to use higher power but incorporate safety googles that look like sunglasses into his act. Still leaves the audience open to an accident with an accidental flash from his hand held mirror though. I'd have thought it very risky from a H&S point of view.
    Last edited by White-Light; 09-27-2008 at 02:13.

  9. #19
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    RGB, I hear you completely there - obviously H&S is imperative, I'm not sure blinding people would be covered by my public liability......!

    Would there be a way of increasing the beam width of the small round barrelled key ring lasers - I'm thinking an expander would make them too cumbersome, that's if they fitted in the first place. I guess I'd have to go down the DIY high refractive index lens route as suggested by Adam? If that's the case, where would I get these from guys? Unless of course by using a hazer/mister, a <5mw beam would be bright/strong enough for the effect???

    Sorry if I'm not being very clear guys, your help is really appreciated!

  10. #20
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    Rich just to clear up any confusion I may have caused by my smoke comments above, whatever power laser you use, you're going to need haze and / or smoke, as the beams simply aren't visible without. The only way to find out if a low power laser is going to be sufficient will be to try it and video yourself, but again make sure you smoke / haze heavily 1st (most canned smoke is cr*p BTW, I tried that), so you really will need a machine.

    You could try asking the guy on Youtube what power lasers he uses, but remember, just becuase he does it with X power, doesn't make it safe, its all going to depend on a lot of factors.

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