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Fabricating

Fabricating a high wire

By Gretchen Salois

Escaping death prompted an adventure-seeking fabricator to push even further, mastering the high wire

February 2015 - As a rock climber, your hands are anchors, each finger an extension of the body’s overall strength. Scaling summits in Nepal, Europe and Canada, Jamie Hamilton knew the risks and enjoyed the challenge. One day he dropped 50 ft. during a climb onto a quartzite boulder and “I just sort of bounced—the only word I can think of is miraculous, really, because I was FFJ-0211-webex-wire-image5basically unharmed.”

While others may interpret the near-miss as a sign to either scale back or reassess the sport, Hamilton, also a fabricator and sculptor, went the other route. “About three years ago, after the fall, I decided I wanted to combine all these different activities—climbing, fabrication and art—into a single activity,” he recalls. “That day opened my mind in a way self-help books couldn’t. I fell and hit a hard surface—I’m not a physicist but nothing bad happened to me when it should have.”

From a home with a mother who worked as an architect and a sculptor father, Hamilton was no stranger to the creative arts. His background in steel work, woodwork and light rigging structures aided him when he enrolled in a residency graduate program at Transart University, based in New York and Berlin. He paid his way doing fabrication work like structural welding and some rigging jobs in New York. 

Anchoring trigonometry

To combine his rigging and welding experience with his sports interests, Hamilton decided to take up high wire walking. He sets up and builds everything himself, planning out the logistics to factor in the unexpected.

Using a compass, Hamilton employs his trigonometry skills to figure out the distance across a gorge and then calculates the best places to insert the anchors. 

“The anchors are pretty crucial and it can be complicated,” he explains. “You’re working with the earth and these rocks are often fragmented and broken.” It’s not a fixed structure like concrete and weak points aren’t always visible from the surface.

Hamilton uses Simpson AT glue-in adhesive to anchor bolt studs into monolithic rock structures. A custom-fabricated eye nut connects the bolt studs to shackles. He typically sets up two or more anchor points. “I try to go above and beyond the minimal safety factor, the ratio of the anticipated load to the ultimate load a system can support before catastrophic failure. Typically I use a 7:1 ratio. For example, if I am tensioning my wire to 3 tons, I make certain the system will not break at less than 20 tons.” 

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When bolts cannot be used because sturdy rocks are unavailable, Hamilton drives large stakes deep into the ground or fissures in the rock. The stakes must be tested beforehand to ascertain how they will remain in place without excess deflection or upsetting the material into which they are driven. 

Using 5/8-in. galvanized wire rope or Samson Tech 12 high modulus rope, Hamilton often climbs up one side of a gorge to install anchors; heads back down and up the opposite side to install anchors, and tediously hauls the wire across. 

In creating the anchors he sets up bridles that distribute equal amounts of load onto each bolt or stake. “I use an extending bridle so if one point within the anchor fails, the bridle lengthens, slackening the wire or rope, thus avoiding the potential for a zipper effect of sequential failures,” he explains. 

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The wire needs to be stabilized and able to handle oscillations. “These oscillations and instability of the wire are mitigated by cavaletti, low stretch ropes which attach perpendicularly to the wire and are tensioned to the ground, similar to the guy wires of a radio tower.”

He doesn’t use a balancing pole, preferring to freehand it across, walking from one end to another introducing oscillation into the wire as he adjusts his balance. 

Premeditated process

A lot goes into these preparations, from engineering it to load tables and testing each component individually. His experience with demolition work exposed him to different brands of components; he chooses those that prove most consistent. He prefers American-made shackles because “you need to know those things are good to go.” 

He uses a Hypertherm Powermax 85 and plasma cuts often. “I use a hand torch, mostly with self-made circle straight edge and beveling jigs. I mostly cut hot-rolled steel plate from 1/4 in. to 1 in. but I also use the plasma to create points on the ends of my stakes that are sometimes as large as 2 in. diameter hot-rolled [wire] rod,” explains Hamilton. “I also make my own truss towers and use a JD2 notcher to cope tubes for welding.“

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He TIG welds everything together with a Miller Dynasty. “I love the TIG process. After years of running flux core wires overhead, I appreciate the lack of sparks, the absence of slag raining down, and the quality of weld,” he says. “With TIG I can be absolutely certain I am not getting any cold laps and the fusion is perfect, something that helps keep my mind at peace when I am out on a high wire, held up by my own welding.” 

Hamilton plasma cuts with a template and goes in and grinds material to get rid of slag on edges so there is no contamination in his welds and uses simple clamping methods during the process. 

“I have a plywood table with a piece of 1/8-in. steel on it and I’ll weld and clamp together stiff tubes so I have a makeshift welding table—that’s an investment I have next on my list,” he says.

His labor of love is self-funded. “I live inexpensively [but I] get to enjoy living my nontraditional approach to making a living,” he says. “If we’re just doing something for an outcome, we miss the moment of the doing, which is really where you find joy or pleasure of discovery.” FFJ

 

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