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Bizarre LX/safety/practicals Q

Discussion in 'Lighting and Electrics' started by Nephilim, Jan 11, 2004.

  1. Nephilim

    Nephilim Active Member

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    We're doing Inspecting Carol, a show about a theater company being inspected by National Endowment for the Arts while preparing to do A Christmas Carol for their fundraiser.

    At one point, one of the ghosts needs to be low-backlit in a doorway, then step out of the doorway and yank the backlight with them on the chains at their feet, then proceed to throw the fixture around the set whilst the SM characted madly tries to cut it loose.

    My thinking at the moment is to use a beat-up fresnel we have (and oh, we have plenty) and put an in-line dimmer and plug it into the wall backstage. I would then splice in some kind of disconnect into the cable and secure the non-fixture side of the cable to something solid.

    Is this a bad/unsafe idea? Any thoughts as to what materials to use or alternative ways to do this?

    We are an Edison house, by the way (Yes, I know.)

    Cail
     
  2. ship

    ship Senior Team Emeritus Premium Member

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    A few questions first.

    Does it need to be on/working while dragged about the stage? Can the audience see the fixture when it’s backlighting the ghost? Why does the fixture need to be on a dimmer? Why would you want to trash a Fresnel when halogen work lights are so cheap?

    We are talking about something that’s possibly dangerous if the fixture needs to be lit while dragged about the stage, if it can be off that’s much safer in both an electrical and glass on stage way. Your Fresnel (lens removed) with a BTN lamp could possibly survive a bunch of bouncing about the stage, at least better than most other fixture lamps, but if the lamp should break that’s fairly dangerous still, much less it could blow and shoot a hot glass bulb across the stage or into the audience. Should this be the way you want to do it, I would add at least 1/4" hardware cloth into the lens slot that's well supported. Better yet, use aluminum window screening. Won't keep all the glass particals out but it would prevent a hot lamp from hitting someone.

    If the fixture does not have to work, I would remove the glass and lamp from one of them dime a dozen work lights you find at home centers, figure out a way of attaching it to the chain, remove the lamp and lens. Than have someone back stage hold the instrument as if the real stage lighting fixture that was a moment ago back lighting the stage. When the actor pulls on the chain, the real Stage Manager gives the lighting cue to kill the back light circuit, and a stage hand throw/drops the simulated fixture to be dragged about the stage as if it were yanked off it's mounting. The old switcharoo given the audience does not ever see that back lighting fixture in the first place.

    If they are to see it, or if the fixture is to be in use while dragged about than I would not use the security light. They use safety glass that would explode all over the stage and the lamps are more fragile plus pop out of their bases. Instead go back to the Fresnel idea but take out the lens of what ever you end up using.

    You might go to a source like Grainger or McMaster Carr and get a silicone or Teflon coated incandescent A-19 lamp. Mount a medium screw base into the fixture instead of the medium prefocus one in it. Use something like a 2" square mounting base - surface mounted plastic lamp base over that of a porcelain one. These silicone and Teflon lamps are shatter proof and if the rough service type might even survive some crashing about the stage while lit. In other words, it might break, but it’s not going to spread glass all over the place. Such a lamp would also in anywhere from 60 to 100 Watts do a OK job of backlighting if supplemented by other fixtures.

    With the proper lamp in the fixture also, it given it even has to work would not need a dimmer.

    Only stipulation I would have is to have a stage hand back stage to throw the fixture rather than relying the actor to yank the fixture off the wall and not take down the set. Could be as simple as some sort of trip line to release it from the wall if that fixture needed to be seen ripped off the wall, but I would rely on hands back stage over the magic of the night to get it right. Same with the power cord. What’s to stop the cord from coming loose in it’s strain relief, getting caught in something or other wise breaking with a cut broken cord live on stage? Have a stage hand with that cord page it onstage than to disconnect it given it needs to work. Much more reliable that way. You can place the fixture on stage dimmers for a secondary safety factor so the people in the booth can shut it down should something go wrong, but the stage hand should for the most part - especially if on headsets, be able to take care of most problems.

    Avoid your some kind of disconnect idea unless you go to a Bates style Stage Pin Plug that will have a hole within the plug and connector that can be used to screw the plug to the scenery. On the male plug you can bend it’s spread pins together some to make it easier to yank free and have the female end attached to the wall. Otherwise with the stage hand, unplugging while not nice is most effective with the Edison cord than with some other possibly not UL listed for your purpose equipment.

    One last thing, you will want to ensure that the fixture is grounded really well. Make sure no strain reliefs are loose or terminals holding any of much less the ground wires are loose. Don't want anything to go spark in the night that's not in the program.
     
  3. Nephilim

    Nephilim Active Member

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    I think I may go for the switch routine - it doesn't need to be lit when it's being thrown around, so we'll just have an empty fresnel getting trashed. Thanks for the injection of sanity :)

    Cail
     
  4. DMXtools

    DMXtools Active Member

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    I'd wrap a fairly bright maglite or similar rugged flashlight in a lot of foam rubber and jam it into the fixture body (old, trashed fixture) - it wouldn't actually provide the backlight, but would remain lit while being bounced around onstage (huh? how the heck?!?...), with no cord to disconnect. Super-glue an Edison plug to a piece of black nylon rope and superglue that to the fixture strain-relief to give the appearance of it being unplugged. Just a thought...

    John
     
  5. Nephilim

    Nephilim Active Member

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    Cool idea, although I don't see why I'd cut off the existing tail the beat-up fixture has...
     
  6. DMXtools

    DMXtools Active Member

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    Safety. Just in case someone actually plugs it in.

    John
     
  7. Nephilim

    Nephilim Active Member

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    Good point.
     

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