Tab Curtain Question

Painterspoon

Member
Joined
Nov 27, 2011
Location
Near Peterborough, Ontario
@JChenault Not to veer TOO far. In a similar manner, a friend used to borrow a local goup's mirror ball once a year for his church's annual young peoples' party. The mirror ball was a British Furse approximately 24" in diameter, aluminum and glass (not plastic) covered, with a 120 volt internal rotator; not exactly a light weight orb. Year after year, one of his church members would stretch plastic coated clothes line perhaps 60' across the width of the curch from a polished brass hand rail on one choir loft to its mate on the opposite side. My buddy was a bus driver who worked until 1:30 a.m. Keith would finish work then go to his church around 2:00 a.m. and use a 12' ladder to suspend the mirror ball from the center point of the taught clothesline then spiral an extension cord around the taught line to a 120 volt receptacle in one of the choir lofts.
The first few years, he borrowed a pair of 6 x 22 Altman 360Q's and hung one on either choir loft hand rail to cross light the ball, often in green and red for Christmas.
After getting away with this for several years, Keith wanted to up the intensity on the ball by eliminating the Altman 6 x 22's and replacing them with a pair of small ACL pars c/w 120 to 24 volt transformers. The pair of ACL's, and their transformers, were added to the taught clotheline approximately 3 or 4 feet either side of the mirror ball. A second extension cord was spiraled out with a two-fer added to power the ACL's. A Variac was positioned in one of the choir lofts to vary the intensity of the ACL's.
Keith wasn't using any old extension cords, no. Keith was borrowing 12 or 14-3 black Cabtire with Twist locks, a twist lock two-fer and three twist to parallel blade adapters to power the ball rotator and ACL's.
Miraculously Keith and his young peoples' group got away with this for another year or two.

Keith wanted to up his game one more time. The local amateur group didn't own any color scrollers or wheels but Keith knew where he could borrow two more ACL's. One night / morning, Keith rolled in after work at 2:00 a.m. and hung four ACL's, two either side of the mirror ball. Each ACL had its own step down transformer and Keith borrowed a second Variac so he could swap color pairs from within one of the choir lofts.

Think about it: The taught plastic coated clothesline sagged a little more each year becoming essentially a 160 degree bridle 60' bridle supporting a 24" glass covered mirror ball with its internal rotator, plus four ACL's, each with their own step down transformer.
The first year Keith hung four ACL's, he vacated around 4:30 a.m. with everything neat and tidy prior to the cleaners arriving around 6:00 a.m.

The cleaners were somewhat surprised to find a mirror ball and four ACL's et al in the middle of the church's central aisle in a tangled mess.
The priests were STARTLED to find one of the polished brass hand rails torn from its choir loft and laying in one of the church's side aisles.
I'm sure I've posted of this at least once before, perhaps @egilson1 and / or @What Rigger? would care to comment??
Had this not been a church with God watching, she likely would've let the whole abortion fail several years sooner.
Toodleoo!
Ron Hebbard
I don't feel like such a doink now!
 

What Rigger?

I'm so fly....I Neverland.
Joined
Aug 24, 2006
Location
PPT.
For @SVF 's benefit. possibly someone will post a photo of their favorite, simple to fabricate, line lock suitable for traveller operating lines and / or operating lines on counter-weighted system pipes. I'm thinking of one of the simple designs, possibly one fabricated from a 12" x 4" scrap of 3/4" plywood with a slot for the operating-lines cut half-way across 1.5 to 2 inches from one end of the ply and a 3/8" threaded open-eye hook bolted securely through the opposite end of the scrap of ply.

(For those playing along at home:) You hold the length of ply vertically at approximately waist height with the slotted end down and the end with the hook up and facing towards the operating lines. Slip both operating lines all the way into the slot then lift the other end of the plywood up forcing a pair of close to 90 degree bends into the pair of operating lines, hook the open eye-hook around both operating lines and MISSION ACCOMPLISHED:
The open-eye hook keeps the plywood standing vertical while the slot in the plywood securely captures both the operating lines with a pair of nearly 90 degree reverse bends 3/4" apart. Simple, easy to fabricate from scrap wood, and only the cost of one 3/8" threaded open eye hook, two hex nuts, two flat washers and a lock washer to be thorough or spring the extra few pennies for a pair of Ny-Locks.
There are other easy designs bent from 1/2" diameter steel rod but not every shop as the ability to crank smooth tight bends into 1/2" diameter steel rod.
@Van @What Rigger? @anyone else Have you any comments or other cheap 'n cheerful, yet easy, quick and damage-free designs to pass along??
Toodleoo!
Ron Hebbard
Well, there's a few things in here I'm not clear on and the sort of DIY nature of all the things we're talking about here gives me definite pause. Anyone got a quick sketch of what you're hoping the end result will be? Any photos of the venue this is to be done in?
 
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What Rigger?

I'm so fly....I Neverland.
Joined
Aug 24, 2006
Location
PPT.
@JChenault Not to veer TOO far. In a similar manner, a friend used to borrow a local goup's mirror ball once a year for his church's annual young peoples' party. The mirror ball was a British Furse approximately 24" in diameter, aluminum and glass (not plastic) covered, with a 120 volt internal rotator; not exactly a light weight orb. Year after year, one of his church members would stretch plastic coated clothes line perhaps 60' across the width of the curch from a polished brass hand rail on one choir loft to its mate on the opposite side. My buddy was a bus driver who worked until 1:30 a.m. Keith would finish work then go to his church around 2:00 a.m. and use a 12' ladder to suspend the mirror ball from the center point of the taught clothesline then spiral an extension cord around the taught line to a 120 volt receptacle in one of the choir lofts.
The first few years, he borrowed a pair of 6 x 22 Altman 360Q's and hung one on either choir loft hand rail to cross light the ball, often in green and red for Christmas.
After getting away with this for several years, Keith wanted to up the intensity on the ball by eliminating the Altman 6 x 22's and replacing them with a pair of small ACL pars c/w 120 to 24 volt transformers. The pair of ACL's, and their transformers, were added to the taught clotheline approximately 3 or 4 feet either side of the mirror ball. A second extension cord was spiraled out with a two-fer added to power the ACL's. A Variac was positioned in one of the choir lofts to vary the intensity of the ACL's.
Keith wasn't using any old extension cords, no. Keith was borrowing 12 or 14-3 black Cabtire with Twist locks, a twist lock two-fer and three twist to parallel blade adapters to power the ball rotator and ACL's.
Miraculously Keith and his young peoples' group got away with this for another year or two.

Keith wanted to up his game one more time. The local amateur group didn't own any color scrollers or wheels but Keith knew where he could borrow two more ACL's. One night / morning, Keith rolled in after work at 2:00 a.m. and hung four ACL's, two either side of the mirror ball. Each ACL had its own step down transformer and Keith borrowed a second Variac so he could swap color pairs from within one of the choir lofts.

Think about it: The taught plastic coated clothesline sagged a little more each year becoming essentially a 160 degree bridle 60' bridle supporting a 24" glass covered mirror ball with its internal rotator, plus four ACL's, each with their own step down transformer.
The first year Keith hung four ACL's, he vacated around 4:30 a.m. with everything neat and tidy prior to the cleaners arriving around 6:00 a.m.

The cleaners were somewhat surprised to find a mirror ball and four ACL's et al in the middle of the church's central aisle in a tangled mess.
The priests were STARTLED to find one of the polished brass hand rails torn from its choir loft and laying in one of the church's side aisles.
I'm sure I've posted of this at least once before, perhaps @egilson1 and / or @What Rigger? would care to comment??
Had this not been a church with God watching, she likely would've let the whole abortion fail several years sooner.
Toodleoo!
Ron Hebbard
As for this, yeah, sounds like someone accidentally (or unwittingly) made a 60' flat bridle. And as we know (or perhaps are learning for the first time), in a 160 degree bridle as Ron says, the load on each leg (that is, each side of the string assuming the load is in the middle) is equal to 300% of the actual object hanging in the middle. So if the object is 100 pounds....
In a 180 degree bridle (a flat bridle), the resultant load on each side of the bridle could well push to 1000% (one thousand percent) of the load. Suddenly, disco balls are more deadly than decorative.
 

TimMc

Well-Known Member
Joined
Feb 15, 2017
As for this, yeah, sounds like someone accidentally (or unwittingly) made a 60' flat bridle. And as we know (or perhaps are learning for the first time), in a 160 degree bridle as Ron says, the load on each leg (that is, each side of the string assuming the load is in the middle) is equal to 300% of the actual object hanging in the middle. So if the object is 100 pounds....
In a 180 degree bridle (a flat bridle), the resultant load on each side of the bridle could well push to 1000% (one thousand percent) of the load. Suddenly, disco balls are more deadly than decorative.
A little exercise I've done that requires 2 stout persons, and 2 spring "pull scales", some rope, and 2, 5, and 10 lb weights. Use a 5-ish foot length of rope to one scale, then another 10 foot length on the other side. Have your 2 stout persons stretch the rope at shoulder height and then hang the second scale from the center, and start adding weight under it. Have the stout folk try to keep the rope taught as the weight is increased and note the horizontal scale readings. Then get them up a few feet over the floor and simulate a 90° (45° legs) with the same increasing load and note the scale reading in the bridle leg. It's an eye-opener and surprised the human anchor points at the tension required to keep the line horizontal with the smallest weight.
 

danTt

Well-Known Member
Joined
Aug 24, 2011
Location
NY
As for this, yeah, sounds like someone accidentally (or unwittingly) made a 60' flat bridle. And as we know (or perhaps are learning for the first time), in a 160 degree bridle as Ron says, the load on each leg (that is, each side of the string assuming the load is in the middle) is equal to 300% of the actual object hanging in the middle. So if the object is 100 pounds....
In a 180 degree bridle (a flat bridle), the resultant load on each side of the bridle could well push to 1000% (one thousand percent) of the load. Suddenly, disco balls are more deadly than decorative.
Does it push 1000% of the load as a result of the weight or as a result of the force necessary to keep the line horizontal? I'm not a genious, but I feel like one of the reasons you see such high force numbers at a flat bridle is because lines will naturally deflect if the force isn't there to keep them horizontal.
 

BillConnerFASTC

Well-Known Member
Joined
Jan 30, 2010
Location
Clayton NY 13624
As I said, I was a part of the team doing this once, and in charge another time. I'm sure there was 6-12" if sag. And it was a light weight curtain - scrim like. But a 30-50 pound curtain is at 1000% only 300-500 pounds - not much for wire rope and anchors. Not like Ron's buddies hanging lights and mirror balls.
 
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RonHebbard

Well-Known Member
Premium Member
Joined
Jun 12, 2004
Location
Waterdown, ON, CA
As I said, I was a part of the team doing this once, and in charge another time. I'm sure there was 6-12" if sag. And it was a light weight curtain - scrim like. But a 30-50 pound curtain is at 1000% only 300-500 pounds - not much for wire rope and anchors. Not like Ron's buddies hanging lights and mirror balls.
Also, the weight of your scrim is spread across the entire (or close to it) length of the taught wire, at least until it's all gathered at one end.
Clearly this is appreciably different than applying all of the weight in the centre of the taught wire.
Toodleoo!
Ron Hebbard
 

BillConnerFASTC

Well-Known Member
Joined
Jan 30, 2010
Location
Clayton NY 13624
Also, the weight of your scrim is spread across the entire (or close to it) length of the taught wire, at least until it's all gathered at one end.
Clearly this is appreciably different than applying all of the weight in the centre of the taught wire.
Toodleoo!
Ron Hebbard
And I'm not sure a 15' high scrim "falling" is a terrible hazard. But still needs competent people to rig, no matter how simple and straightforward. Does depend a lot on what the construction is. The one I did myself was anchored to major columns and I was not worried by a few small turnbuckles and 1/8" or maybe 3/32" wire rope pulling the building down.
 
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