Results 1 to 2 of 2

Thread: Announcing: "The ol' fart's hey days"

  1. #1
    Join Date
    Sep 2014
    Location
    Colorado USA
    Posts
    793

    Default Announcing: "The ol' fart's hey days"

    In the Radiator thread I had stated:

    I'd sure like laserist to elaborate more on this, but my first look at a Laserium projector astounded and impressed me in that it was made from a 19" relay rack enclosure, not sure if it was a standard 42U rack, but it shed light (no pun intended) on the notion of vertically mounting the laser or at an angle slightly tilted. They used Spectra Physics 165 Krypton ion lasers if I recall which required 208/240 3 phase power and a 30 circuit breaker. Their vertical projector racks were a great idea to minimize the laser projector's foot print. I was always concerned about "no seeums" falling on the lower mirror reflector over time. Even though the mirrors were covered, stuff seemed to find its way in, especially turning cleanings.

    I started out with a Coherent Radiation CR-MG (mixed gas, krypton/argon) which had about the same output power. Both required 208/240 volt 3-phase at 30 amps max.. This meant their power cables had to be 8/4 (8 gauge stranded wire/ 4 conductor). Hubble twist-lock connectors were our standard. (We used 6/4 cables for the Spectra 171 5 watt Krypton or 20 watt Argon lasers). The travel cases that carried the pigtails and power cable runs were extremely heavy.

    Water pressure levels for cooling these ion lasers were critical, as the water cooled lasers had water flow/pressure cutout switches in their power supplies so that if insufficient water pressure and flow occurred the laser power supply would switch itself off. This was not something you wanted happening during a show, any kind of show. Therefore, also included in our standard "equipment load-out" were 110vac, water pressure boost pumps with 40 PSI regulators on their outputs. We used heavy duty garden type hoses for water runs, which could be as long as 150 ft. for the supply and drain hoses, each.

    Water and power travel cases made up the bulk of cases with their numbers being 4-5, depending on the venue. Site surveys of each venue, in advance, helped determine where the stadium or auditorium power disconnects could be provided for our pigtail connections and the length of our runs needed to get to the laser projector location. Same for water and drain sources.

    (A power pigtail is a 3-6 ft length of 8/4 or 6/4 cable with a Hubble twist-lock connector on one end and bare insulated wire leads about 6-12" long on the other end with about 1" of each lead end stripped back to the stranded copper. The stripped back ends would tie-in (connect) to the venues power breaker box lugs or power disconnect box lugs that housed the main circuit breaker for that power run.)


    How about it you ol' farts? Add to this for posterity.

    Edit: Later I got to thinking (remembering) those who used ion gas lasers for our light sources also had on hand a gallon each of spectral grade Acetone and spectral grade Methanol for cleaning the laser's two Brewster windows and their front and rear mirrors. We carried much smaller squeeze bottles on the road and for everyday use, each filled with these cleaning chemicals, one for the acetone and another for the methanol along with camera lens cleaning tissues used in the process. In my experience, the Spectra Physics 165 and 171 lasers needed far fewer Brewster and mirror cleanings compared to the Coherent Radiation's CR-K and CR-MG, and Laser Ionics 554 MG laser heads.
    ________________________________
    Everything depends on everything else

  2. #2
    Join Date
    Jan 2006
    Location
    Charleston, SC
    Posts
    2,147,489,446

    Default

    Did several shows at the Tabernacle in downtown Atlanta back in 2006 - 2008 with Dreambeamz. (Paul Van Dyk, Tiesto, that sort of thing.) Had a Coherent I-90 mixed gas with an 8 channel PCAOM that probably made 3 watts (all lines), plus another solid-state RGB (think it was ~ 1.5 watts) and a pair of 2 watt dpss greens. Dragging the 3 phase cable all over the stage and up the scaffold to run the Coherent was a huge pain in the ass, because although the venue had cam-lock fittings backstage, they were a good 150 ft from where the laser had to be. Then we had something like a 200 ft run from the water spigot to the stage, and another 200 ft run back to the drain! At least they had good water pressure...

    Worst part of the whole gig was the fact that you couldn't park anywhere near the backstage entrance, and they didn't have a loading dock either. The production company set up a bunch of aluminum ramps so you could push your rolling flight cases up a shallow 70 ft ramp from the sidewalk to the backstage door, but it was still a long damned push. (And that was after you had rolled everything from the back parking lot up to the sidewalk behind the building...) Plus the whole place was just nasty.

    Did a show with David Zurcher at the Navy Base in Guantanamo Bay, Cuba where we were flown to the base on a Navy C-12 (basically a tiny 9 passenger twin-engine turbo-prop plane; it's a military version of the Beechcraft King Air). They pulled most of the seats out of the plane, and we took everything out of the flight cases, all to save weight, but even so they couldn't load enough fuel to get us from Charlotte to GTMO without stopping for gas in Ft Lauderdale first. We brought 3 solid state RGB projectors, two solid state RGY projectors, a Lexel 95 Argon, a Coherent Starlight II mixed-gas, and a 3 watt solid-state blue beam rail. Ran the whole show off a big ass diesel generator, and once again we were hauling 3-phase cable all over the place. (Genny was about 200 ft from the stage.) Had to run two separate water lines (400 ft each) to get water to the lasers, and pressure was iffy at best. Fortunately, we only needed a short 30 ft drain hose, as there was a cliff behind the stage that ran down to a swamp, so that's where we drained the water. Some asshat shut off the water spigot feeding the Lexel right before the encore, so we lost that laser for the last number. (Thankfully the tube was OK, even though it was running at full tilt when the pressure switch killed it...)

    Did a show in Washington DC a few years ago with those same two ion lasers (the Lexel and the Coherent Starlight) along with a bunch of other solid state gear, and it started raining during the setup. Ended up getting water inside the 3 phase distro (we were running off a generator again) which tripped one of the breakers in the panel. When I reset it I got the shock of my life (208 *hurts*), but fortunately the breaker held and we were able to complete the show.

    These days I actively avoid any show that includes gas lasers. You can get 20 watts in a solid state package that isn't much bigger than a car battery these days, so why bother with the hassle of heavy cable and long runs of garden hose, not to mention the last-minute panic when you realize you need to walk the mirrors again because you lost the red in your mixed-gas laser after someone carelessly dropped it on the scaffold during setup... I won't lie that when I was younger I enjoyed working those shows, but there's no way in hell I'd be able to pull them off with that equipment today.

    Adam

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •