How to rig odd boom setup

[SteveB]

We have had a request from a student designer, desiring to add side light to a painted star drop, to rig a 20 ft. boom with assorted Altman Ground Cyc units as well as S4 26 deg. units. PDF attached.

One thought is to hang on the deck all the Ground Cycs, then raise to vertical using an adjacent winched electric (1700 lbs capacity, with a spanset and shackle to the boom tie-off ring, then tie off to grid, then add all S4's from a JLG lift.

I admit to never having to rig something that complicated and am getting nervous at the prospect.

Idea's ?, concerns ?....

 

[gafftapegreenia]

Could you split the difference and do some as tail downs from the electric and others on shorter booms?

Do you have a grid in your space?

 

[SteveB]

Could you split the difference and do some as tail downs from the electric and others on shorter booms?

Do you have a grid in your space?

Fly tower with grid at +42ft. Thus rope or aircraft cable tie-off. Possibly exploring horizontal support with 1-1/2" pipe to other/building structure, for piece-of-mind.....

 

[theatricalmatt]

I really loathe pre-hanging units and then raising booms. It makes the entire thing awkward and ugly, heavier than it really should be and impossible to find a good hand grip. Plus, too many instances with lights slipping or sliding.

Here's how I would do it. Rig the side-arms on the pipe. Raise the pipe into location and secure it -- hopefully it's attached to something secure at the top, or at least picked off to the grid and kept under tension.

Then, drop a haul line from the grid. With someone on the ladder, fly the cyc lights out to their proper position, while the person on the ladder tightens them onto the boom. Probably better to use half-cheeseboroughs than c-clamps, if you have them available. Easier to tighten, especially when you may have to reach around another unit to get to it. Work your way from the top of the boom down. You can alternate hanging units on sidearms with cyc lights.

There are a couple of instances where the clamp of a cyc light is at the exact location that a sidearm is at. Your student designer should have seen this when he or she drafted this, and made some sort of adjustment. A few inches up or down shouldn't matter to a cyc light. I would also go ahead and double check the actual dimension of the units you have in inventory. Source Fours are pretty typical, but I've come across more than one designer who used a different striplight symbol than the actual physical unit they were dealing with, and rued the result.

How close are these to a wall or set piece? I always shake my head at designers who spec out novel hanging locations without any thought as to how someone will get up there to focus, or change a lamp or burnt-out gel.

 

[SteveB]

Matt, all good points. The bitch with the Altman Ground Cyc's is they are 5 ft. long @ 70 lbs ea. Thus 2 people in 2 separate Genies/lifts required, plus add'l folks to haul, using the method you described to haul the units into place. Big PITA, thus the desire to pre-rig maybe the top 3 strips. and as we have a winch it's tempting to partial pre-rig and walk up.

Not concerned about the LD's drawing issues with S4 side arm placement. The S4's will go where they can fit and it's only 2 fixtures whose arms and strip c-clamps interfere. Strips placement takes precedence.

 

[MNicolai]

I'm not sure I'd give this a try on a single side boom pipe. At that length and with those number of fixtures, you're likely to bend your pipe out of whack if it doesn't fall over first. This is the sort of endeavor better pursued with truss.

 

[mikeydoesstuff]

Not to challenge your design, but I'd switch to a more manageably sized unit - Mr-16 or R40 strips.

 

[cbrandt]

I second truss. It gives you more room to work with, and a sturdier platform for all those lights.

 

[SteveB]

Not to challenge your design, but I'd switch to a more manageably sized unit - Mr-16 or R40 strips.

Not enough fixtures available as the dept. owns 4 L&E Mini-Strips, but the LD is concerned not enough coverage vertically, as there are 2 booms, 1 ea. SL & SR. They own 8 Ground Cycs.

 

[SteveB]

Not enough fixtures available as the dept. owns 4 L&E Mini-Strips, but the LD is concerned not enough coverage vertically, as there are 2 booms, 1 ea. SL & SR. They own 8 Ground Cycs.

I'm actually thinking this is a perfect application for pre-viz software to figure it out in advance.

 

[Footer]

I would not Iwo Jima that thing up. Hang it vertical or go with truss. You are going to be putting a lot of pressure on the threads and I really think you will run the risk of failure. Personally, I don't like seeing booms over 12' tall. 1 1/2" sch 40 is not meant to be used in that long of a span unsupported. You will get bending and you will get a ton of force exerted at the boom base. The threading process weakens the pipe, you don't want to put pressure on that if you can avoid it. Even with a point to the grid you will have that issue unless you can put it on a motor (or large turnbuckle) and take 90% of the weight. A rope will just keep the thing from falling over. Get two sticks of 12x12 truss and a plate and go nuts.

 

[SteveB]

I would not Iwo Jima that thing up. Hang it vertical or go with truss. You are going to be putting a lot of pressure on the threads and I really think you will run the risk of failure. Personally, I don't like seeing booms over 12' tall. 1 1/2" sch 40 is not meant to be used in that long of a span unsupported. You will get bending and you will get a ton of force exerted at the boom base. The threading process weakens the pipe, you don't want to put pressure on that if you can avoid it. Even with a point to the grid you will have that issue unless you can put it on a motor (or large turnbuckle) and take 90% of the weight. A rope will just keep the thing from falling over. Get two sticks of 12x12 truss and a plate and go nuts.

Yeah, this is why all the alarm bells are going off. End of story for this concept.

Thanks to all.

 

[microstar]

Just a question... Would not side lighting a painted drop just highlight any wrinkles?

 

[SteveB]

Just a question... Would not side lighting a painted drop just highlight any wrinkles?

The drop is a very dark blue/purple painted star/galaxy drop and will be stretched as well as having a bottom pipe.

For a number of reasons, communication with the LD is problematic and we do not have a clear understanding of the intent of the S4 26 deg. units. Our guess is an attempt to replicate the Don Holder Lion King backdrop concept.

Thus am reluctant to approve the boom design and will probably recommend a 21 ft tall box truss design, floor plates, grid aircraft cable with turnbuckle design if the faculty adviser insists this is the best fixture choices for the design concept.

 

[DELO72]

Not enough fixtures available as the dept. owns 4 L&E Mini-Strips, but the LD is concerned not enough coverage vertically, as there are 2 booms, 1 ea. SL & SR. They own 8 Ground Cycs.

The problem with fixtures like Ground cycs and heavy (old R40 style) strip lights is their hanging hardware and threaded points aren't designed to take that kind of weight (and weren't designed to be hung vertically), so you are creating high-risk situations were you might strip out the yoke hole and/or bend the side arms. This happened to us when we tried to hang a series of R40 Altman striplights on top of each other. It was a nightmare. Best bet IMHO is to find another, safer solution designed to be hung vertically. Rent fixtures maybe, or borrow from another theatre?