Methods of Splicing Pipe

derekleffew

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As promised/threatened in this thread http://www.controlbooth.com/forums/question-day/22761-why-pipe-battens.html#post201164 , I thought a discussion of various ways to make a pipe longer might prove beneficial.

a. Welding end to end, butt splice

b. Threading and couplers pvcplr750x550.P.jpg

c. Inner spline (sleeve) and bolts or blind rivets or plug welds.

d. Expanding splice such as The Light Source's Mega-Quick Pipe Splice image.jpg and Rose Brand's Expanding Batten Splice Expanding-Batten-Splice.jpg .

e. Exterior sleeve, such as Kee Klamp #14-Straight Coupling fitting image_8.jpg

f. Other?

Pros/cons for each of the above?
 

TimmyP1955

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I would not consider anything other than D, and even then, the pipe would need to be rotated such that the plates are on edge for maximum strength. However I'd feel better if they were longer.
 

mstaylor

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As promised/threatened in this thread http://www.controlbooth.com/forums/question-day/22761-why-pipe-battens.html#post201164 , I thought a discussion of various ways to make a pipe longer might prove beneficial.

a. Welding end to end, butt splice

b. Threading and couplers View attachment 4285

c. Inner spline (sleeve) and bolts or blind rivets or plug welds.

d. Expanding splice such as The Light Source's Mega-Quick Pipe Splice View attachment 4286 and Rose Brand's Expanding Batten Splice View attachment 4287 .

e. Exterior sleeve, such as Kee Klamp #14-Straight Coupling fitting View attachment 4288

f. Other?

Pros/cons for each of the above?
A. Welding is a fine method for extending pipe as long as it is not done to a threaded section, the threads need to be cut off.
B. Couplings are fine as long as you are supporting it on either side.
C. Intersplicesare good but I would stick to bolts as opposed to blind rivits or plug welds, a little more stupid proof.
D. Have not used either product so I will leave it alone.
E. Never in a million years.
 

chausman

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I don't think you would call this splicing the pipe, but at a high school I did a show at, they had a few battens that just a long piece of smaller pipe fitted in the batten and when you wanted it longer for what ever reason, you could just loosen the bolt and slide it out. then tighten the bolt again. Is that something you would normally do?
 

FatherMurphy

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a) Welding end to end is only as good as the person doing the welding. Improper preparation or process could lead to failure, and getting a good straight joint can be an issue.

b) As was pointed out to me in a Glerum/Donovan seminar years ago, couplings are designed to withstand internal pressure, not outside structural forces. They're fine for holding ends in alignment in 'supported on both sides' applications, but shouldn't be considered for more strenuous uses.

c) Plug welded internal splices are my favored joint. If you have good burn-in into the splice with the welds, there's no way it can come apart again, and weld shrinkage won't pull the joint out of line. Once the weld is ground off, you have a smooth joint that is free of obstructions and injury hazards.

d) Fine for bottom pipes in drops, not sure I'd want them anywhere permanent or load bearing. What happens if the set screw works loose?

e) Both a big blob on the pipe, and a set screw that can work loose - ok for temporary light duty stuff, but not for permanent or overhead.


The telescoping extension mentioned above is somewhat common, the main things to watch for is if the extension itself can come free of the main batten and fall, and if the far end is properly supported for whatever weight is hanging from it. Some object to permanently installed sliding extensions because the arbor capacity for the weight of the extension pipe isn't made available for scenery when the extension isn't being used.
 
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mstaylor

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I agree with the welding comment, it is only as good as the welder. I tend to like it because I was a high pressure steam pipe welder so I know I can put it together properly. Do I trust just anybody's welds, not as much.
 

MPowers

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Pros/cons for each of the above?

Each of the methods have a place and in that place, are the best method. One of the real problems of correct pipe splicing is to determine which method of pipe splicing is most appropriate for a specific circumstance.

a. Welding end to end, butt splice: Good for pressure applications where the pipe contains a gas or fluid, or in a visual structural application where high strength 90 degrees to the pipe axis is not critical.
b. Threading and couplers. Good for pressure applications where the pipe contains a gas or fluid. Also good for pipes used as a bottom weight for drops and scrims. Not suitable for any application where the pipe experiences loads perpendicular to it's axis. Extremely weak and prone to failure at the point where threads start when subjected to bending moments.
c. internal spline. The strongest and most suitable method of joining pipes used as a structural, weight bearing member such as stage rigging battens. Most common length of splice sleeve is 18". Common methods of joining all involve two fasteners on each side of the joint, usually at 90 degrees or "cross bolted" to each other. Fastening methods include bolts, plug welds, blind rivets or hardened roll pins. Bolts are the fastest, cheapest and easiest method but protrude and can catch instruments, tools and hands. Plug welds require welding and proper precautions, on stage but are smooth and very strong. The disadvantage is that they can not be "undone" or disassembled for any reason and must be cut apart if needed. Blind rivets or roll pins (my choice) are actually stronger than bolts but about twice the cost in both materials and labor for installation. The advantage is they can be easily removed if needed and are flush and do not catch or block "C" clamps, tools or hands.
d. Expanding splice: Very good for temporary joints. Not allowed by many architects, consultants and AHJ for permanent installations. Does require access holes to be drilled in the pipe.
e. Exterior sleeve, such as Kee Klamp #14-Straight Coupling: Very good for hand rails, scaffolding and materials racks and storage structures. Often used for temporary light hanging structures such as drop down ladders, wall mount brackets and other structures. Not suitable for stage rigging battens.
 
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mstaylor

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I agree that welded or threaded connections are weaker but fine if supported on either side of the splice. Roll pins are the best retention method for sleeves, although I might argue "easily" removed. :) On occasion they can catch an attitude coming out but at my choice as well. Bolts are the choice if it is a temp pipe.
 

MPowers

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The trick to easy removal is to have a proper punch. The punches I have for removing pins have a short tip about 1/8" long that fits inside the roll pin center. Then a very square shoulder that is the actual punch face. The diameter of the actual punch face is .060" smaller that the diameter of the roll pin and the hole drilled for it. The tip keeps the punch centered on the pin, the close tolerance of the main punch body tends to keep the punch aligned with the hole, but it is small enough to slide through without jamming, assuming the hole was drilled straight through a diameter of the pipe and not off to the side. It also helps to hit the punch very square and not a glancing blow. HTH.
 
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kicknargel

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What do people normally use for method #C: internal spline? 1" (nominal) schedule 40 is the biggest that will fit inside 1.5" sch40, and leaves quite a lot of slop. We've used 1 7/16" solid rod, which fits beautifully, but is a PITA in a lot of ways.
 

FatherMurphy

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JR Clancy sells a splice pipe that fits fairly snugly inside 1.5" Sch 40, but I haven't found a separate source for it, I think Wheatland, the pipe manufacturer has a proprietary die that JRC owns.

1" sch 40 fits nicely inside 1.25" sch 40, but that's a less common batten size.
 

MPowers

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JR Clancy sells a splice pipe that fits fairly snugly inside 1.5" Sch 40, but I haven't found a separate source for it, I...................
H&H Specialties, SECOA, THERN. H&H sells them as a stand alone item in 18" and 24" lengths. THERN only sells them with the batten and rigging. I'm not sure if SECOA sells them as a stand alone item, call and ask. I suspect that most rigging manufacturers sell them with their systems, but again, I do not know individual company policies as to stand alone sales.
 

FatherMurphy

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By 'separate source' I wasn't thinking in terms of other rigging suppliers as much as a source for the raw pipe, in order to buy full sticks and cut my own as needed. MSRP for JRC's splices is $15 each, iirc, which seems a bit high compared to the per-foot price for regular pipe.
 

MPowers

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OH! Bulk source, gotcha. A few years back I sourced a pipe and tube supply somewhere in Illinois, IIRC. They had the product but had a minimum order of$2500.00 which was a lot more tube than I needed. I'll look around this weekend and see if I can find the file with the info. In the meantime, search for manufacturers of structural tubing and pipe, I seem to recall that's how I found the company.
 

Jimmymise

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Here is a picture of a 1 1/2" schedule 40 batten with a pipe extension. The extension is not a standard pipe you can buy at the hardware store. Probably manufactured by one of the companies listed elsewhere in this thread. The white color is the paint on the end of the batten. (The white is part of the 1.5" schedule 40 batten)
 

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gafftapegreenia

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It likely IS standard pipe that has been modified to hold two square head set screws. Neat. Functionally, similar to a Kee clamp, but part of the batten itself.
 

Jimmymise

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It likely IS standard pipe that has been modified to hold two square head set screws. Neat. Functionally, similar to a Kee clamp, but part of the batten itself.
I measured the pipe myself. The batten is standard 1.5" schedule 40. It has two holes drilled into it and two nuts welded on. The extension pipe is NOT standard, at least its not in any of the books I referenced. It fits very snugly inside the 1.5" pipe. I believe it is a custom made pipe, as others have mentioned. The ring welded on to the end is a great addition. Keeps you from losing the pipe inside of the batten, and provides a place to attach a bridle.
 

gafftapegreenia

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I measured the pipe myself. The batten is standard 1.5" schedule 40. It has two holes drilled into it and two nuts welded on. The extension pipe is NOT standard, at least its not in any of the books I referenced. It fits very snugly inside the 1.5" pipe. I believe it is a custom made pipe, as others have mentioned. The ring welded on to the end is a great addition. Keeps you from losing the pipe inside of the batten, and provides a place to attach a bridle.

Oh, my mistake. I didn't know you were referring to the extension pipe specifically. And yes, I love the ring on the end.
 

gafftaper

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I've seen some odd things like this locally produced by theater installation companies. Sometimes they are great, sometimes they make you shake your head and ask why? My guess is it's not a nationally produced product but something dreamed up by a theater designer when your building was constructed and made in a local shop or by a contractor. Someone had a reason that they wanted to be able to extend how wide the batten is. Perhaps they had a setup that required all the cable coming off the end, and they needed to have it way off stage at times.
 
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Jimmymise

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No. This is at the Kaufmann Center for the Performing arts in Kansas City, Missouri, the newest large-scale performing arts venue in the country. I'm not sure who did the installation.
 

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