Jump to content


Photo

Speed-rail weight limits


  • Please log in to reply
12 replies to this topic

#1 Michael Collier

Michael Collier
  • Basic Members
  • PipPipPipPip
  • 1262 posts
  • Gaffer
  • Los Angeles, CA

Posted 21 August 2008 - 09:35 PM

My keygrip is on a shoot, and I have to light a live remote set for election central (local primaries TV coverage).

Because of a lack of baby source-4s, I am modifying my plot at the last minute to have both my backlights and key lights on one speedrail bar behind talent about 15 feet up. The source 4s I can only find pipe clamp mounts, so I figure If i put my backlights on the bar, I still have room to place the source-4s and shine them on 4 4x4 bead boards mounted on a speedrail in front of talent.

I need to do about a 20'-24' span on both bars, mounted on high rollers, and I need to know the speedrail can support the weight. I want to mount (3) 650 arri frennels and (6) source 4s (25-50 degree jr. zoom source 4), all spaced equally (s4 , 650, s4, s4, 650, s4, s4, 650, s4) along the middle 12 feet of the span.

heres the kicker though, I couldn't find 20' of speedrail in town, so I am leaning towards renting two peices of 12' and joining them with a coupler. Given the weight and span, do you think that would be safe? My keygrip hopefully will get back to me, but I can't pressure him when hes off on his other gigs. what is the weight loading rating on a speedrail setup like that?
  • 1

#2 Daniel Wallens

Daniel Wallens
  • Basic Members
  • PipPipPip
  • 214 posts
  • Grip
  • New York City

Posted 21 August 2008 - 11:55 PM

The short answer is, you should be fine. However, keep reading for caveats.

Even though we typically refer to speed rail as aluminum pipe (which it is), real speed rail (typically) is made out of a magnesium-aluminum alloy, grade 535, schedule 40 pipe. In real life, things can always be a little different. First off, you didn't say which kind of speed rail. Standard is 1.25", but it also comes 1.5" a lot of the time (and is manufactured in different sizes when used outside the film world). If possible, 1.5" might be preferable if you can get it. According to Hollaender, their 1.25" pipe is rated at 937 lbs. You also must consider the condition the gear is in. Get a good coupler with 4 tie downs. Make sure the pipe you get doesn't have any huge gouges in it. That can compromise its stability. But considering that the ellipsoidals you'll be using weigh roughly about 10lbs each, and the Arris' weight is pretty negligible (about 7lbs per unit), you should be fine.

Honestly, it is up to your key grip, and I don't want to step on his/her toes. If he/she is experienced and knowledgeable, they will make the right decision, looking at the situation first hand and considering all the variables. If you are nervous, however, consider using an over-under or a trussmaker. Either of these options will provide considerable added stability to your rig. If neither of these, you can put a safety from the pipe to a fixed object above, so some of the weight is taken off (this, however, is the less desirable method).

:)
-DW
  • 0

#3 Jon Rosenbloom

Jon Rosenbloom
  • Basic Members
  • PipPipPipPip
  • 713 posts
  • Cinematographer

Posted 22 August 2008 - 12:07 AM

Better to use 21' black pipe. The aluminum will bow and make everyone nervous, including me - and I won't even be there.
  • 0

#4 Jamie Metzger

Jamie Metzger
  • Basic Members
  • PipPipPipPip
  • 773 posts
  • Cinematographer
  • San Francisco

Posted 22 August 2008 - 12:45 AM

I would feel nervous about the 1.25 but I know it's possible. You would use a 12' and an 8' with a joiner. Usually has 4 hex screws and it's pretty self explanitory. If you can get the 1.5, you'd feel a lot better.
There are ways to ease the pressure from the middle, but I think i wouldn't be able to explain it well enough on the forum. Think menace arm/construction crane.
  • 0

#5 Tshaka

Tshaka
  • Basic Members
  • PipPip
  • 37 posts
  • Grip
  • New York

Posted 22 August 2008 - 01:48 AM

My keygrip is on a shoot, and I have to light a live remote set for election central (local primaries TV coverage).

Because of a lack of baby source-4s, I am modifying my plot at the last minute to have both my backlights and key lights on one speedrail bar behind talent about 15 feet up. The source 4s I can only find pipe clamp mounts, so I figure If i put my backlights on the bar, I still have room to place the source-4s and shine them on 4 4x4 bead boards mounted on a speedrail in front of talent.

I need to do about a 20'-24' span on both bars, mounted on high rollers, and I need to know the speedrail can support the weight. I want to mount (3) 650 arri frennels and (6) source 4s (25-50 degree jr. zoom source 4), all spaced equally (s4 , 650, s4, s4, 650, s4, s4, 650, s4) along the middle 12 feet of the span.

heres the kicker though, I couldn't find 20' of speedrail in town, so I am leaning towards renting two peices of 12' and joining them with a coupler. Given the weight and span, do you think that would be safe? My keygrip hopefully will get back to me, but I can't pressure him when hes off on his other gigs. what is the weight loading rating on a speedrail setup like that?



Michael what we normally do is use black pipe (steel) like Jon suggested when weight capacity of the Speedrail is a concern. The 2 most common sizes we use are 1 1/4" Schedule 40 (like the Speedrail you're used to seeing) and 1 1/2" Schedule 40.

I'd prefer to use the 1 1/2 " because it's more rigid and the span is long but 1 1/4" is fine too. You can use the sleeves (what you call a "coupler") with black pipe as well. Just make sure you get the corresponding sizes (1 1/2" Sleeves for 1 1/2" Pipe).

As far as stands. Hi Rollers will work but if you can manage it then why not use 3 Riser Strato Cranks for the goal post with the lights? The Crank Stands make it easier to raise and lower the lights and they're sturdier.

Speedrail should be fine for the goal post with the Beadboard. Hi Rollers too.

Michael you could also use Truss with the 3 Riser Strato Cranks for the goal post with the lights. That's what I'd opt for if it's a practical choice for your job.
  • 0

#6 Warwick Hempleman

Warwick Hempleman
  • Basic Members
  • PipPipPip
  • 115 posts
  • Industry Rep
  • Germany

Posted 22 August 2008 - 05:48 AM

If there's truss, either triangular or ladder beam, take that, especially before coupling 2x 12' pipes. No sag and no bounce. You mention this is an election coverage set for TV, so there'll be people walking around, and with the single tube you may start getting some bounce in the pipe.

Needless to say, the weight load question will no longer be on the truss / ladder beam, it'll be on your stands. Here I'd say go with the crankups, too- easier to raise & lower than high rollers, and you can cable & rig at the low position and raise it and save yourself a lot of ladder time. You could go all out and get Verlinde-style crankup lifts for truss, if they're available and you're familiar with them.
  • 0

#7 Daniel Wallens

Daniel Wallens
  • Basic Members
  • PipPipPip
  • 214 posts
  • Grip
  • New York City

Posted 22 August 2008 - 10:21 AM

Ah yes, I don't know why I didn't think of steel pipe (my mind was in speed rail land, apparently...). Jon's suggestion of using that was probably the best here.
  • 0

#8 robert duke

robert duke
  • Basic Members
  • PipPipPipPip
  • 438 posts
  • Grip
  • southeast USA

Posted 25 August 2008 - 11:01 PM

If you can get some over/unders you can run double pipe to reduce the sag. If you can't get over/unders you can use swivel chessbourghs. Why not just rent 25ft of 12" box truss from a rental house? Genie stands are great for this application.
  • 0

#9 Reil Munro

Reil Munro
  • Basic Members
  • PipPip
  • 12 posts
  • Grip
  • Manitoba, Canada

Posted 10 September 2008 - 04:50 AM

Robert D

I like your over under idea with the soft 90s...I do the same when in doubt (When there is a doubt, there is no doubt)

Also your suggestion for box trust is rather cool, but my take on that would be to maybe instead get 3 25' speed rails(is you grip truck long enough to hold that length) along with 3 triangle truss brackets, placed equaled apart...it also saves some room when transporting, and as smartly suggested by Warwick, the ckankups are the way to go.

I've never seen piped joined while in use on a truss bracket personally...is that possible ?

Cheers
  • 0

#10 Hal Smith

Hal Smith
  • Sustaining Members
  • 2280 posts
  • Cinematographer
  • OKC area

Posted 10 September 2008 - 03:59 PM

Two years ago I lit a big production of "The Sound of Music" in a mega-church. To create a front of the house lighting position I hung around 800# of Cyberlights, lights, scrollers, and cable off 30' of 20X30 heavy duty Tomcat truss at 20' up hung between a pair of Genie tower lifts. No sway, no problem. We focussed everything with a Genie Lift but it truth is it was stable enough that one could have climbed onto the truss if necessary. Truss is ALWAYS your friend.

PS: To mount S4's, Fresnels, etc. on truss I always use aluminum 1/2 Cheeseborough truss clamps. The big rental place here in town will let you use pipe clamps on their truss if you put pennies under the fastening bolt but they really try hard to talk you out of that...but occasionally everyone's out of truss clamps and they begrudging let you use pipe clamps. If I ever have to do that again I plan on also putting a small square of 18 gage copper sheet under the fixed end of the clamps.
  • 0

#11 Jamie Metzger

Jamie Metzger
  • Basic Members
  • PipPipPipPip
  • 773 posts
  • Cinematographer
  • San Francisco

Posted 10 September 2008 - 05:01 PM

I'm used to using "condoms" which are 3/4 round pvc pipe fittings. It protects the truss from the screw in the pipe clamp.
  • 0

#12 Michael Collier

Michael Collier
  • Basic Members
  • PipPipPipPip
  • 1262 posts
  • Gaffer
  • Los Angeles, CA

Posted 10 September 2008 - 08:19 PM

Thanks for all the suggestions! great to hear all the great advice. I took a lot of it to heart, but had to discarded most of it due to budget concerns. Truss was my first idea, but a no go since it was too costly. The crank ups, great idea, too costly (and there aren't any in state, so I would have had to ship those)

As it was I built the overhead on the ground to see how it would handle the weight before running it up. It did indeed bounce when I was working on lights, but people walking around didn't start them swaying. Once the grid was up it looked rock solid. The stands were easily able to hold the weight without slippage, and the light was BEAUTIFUL. 16x4' of soft wrap with three backlights carefully flagged to create the illusion of parrallell backlight (the overhead was close, so spread had to be handled by many units. I did ditch the 650 arri in favor of omnis, since the omnis are so much lighter, and they were in the middle of the span.

I did carefully restrict access to the light grid for saftey concerns. I even had to tell the GM not to stand directly below it (and beyond the bright orange caution tape) Other than that it went off without a hitch and without me worried at all.

The real issue of the night for me, I was running around with steadicam flying for 2 1/2 hours STRAIGHT! Never got a chance to put it on post, except to change monitor batteries and tape. I only ever got two bottles of water, and they were gone in seconds. That night a beer and a soft couch were my best friend.

Best of all though was that the clients stage looked the most professional and well funded, and thats even trumping the station who has a 60% share in the market. The light actually drew more people to our stage, like moths. Not bad for a number 3 rated station. All night long I heard 'what are you putting on a rock concert?' I said yes, we are mounting the disco ball next.

**edit**

Forgot to mention, it was 1 1/2" speedrail mounted onto jr. pins on hi-hi rollers, 2 12' spans coupled with sleeves, shot baged to all hell.

Edited by Michael Collier, 10 September 2008 - 08:22 PM.

  • 0

#13 Jamie Metzger

Jamie Metzger
  • Basic Members
  • PipPipPipPip
  • 773 posts
  • Cinematographer
  • San Francisco

Posted 20 September 2008 - 12:31 AM

Hey guys, I made sure that I took a picture of the so called "condom". This piece helps protect the truss or any pipe you might want to save from damage. I must admit, the name get's funny looks no matter how many times I hear it.

It's not great, I had a few seconds to snap it.

Hope this clears things up.

Jamie

Posted Image
  • 0


Opal

rebotnix Technologies

Ritter Battery

Technodolly

Aerial Filmworks

Abel Cine

CineLab

Paralinx LLC

Broadcast Solutions Inc

Wooden Camera

Visual Products

Gamma Ray Digital Inc

Tai Audio

Rig Wheels Passport

FJS International, LLC

CineTape

Willys Widgets

The Slider

Glidecam

Metropolis Post

Media Blackout - Custom Cables and AKS

Tai Audio

Abel Cine

Technodolly

Media Blackout - Custom Cables and AKS

FJS International, LLC

CineTape

Gamma Ray Digital Inc

Glidecam

Visual Products

Aerial Filmworks

CineLab

Willys Widgets

Paralinx LLC

rebotnix Technologies

The Slider

Broadcast Solutions Inc

Metropolis Post

Ritter Battery

Wooden Camera

Rig Wheels Passport

Opal