Cool Tools: Conduit Benders
Published: March 2012
Basic hand benders; mechanical benders; hydraulic models for rigid, large-diameter conduits; sophisticated, computer-controlled bending equipment for high-volume production; and hot and cold bending options for PVC—the wide range of bending equipment available today meets the needs of virtually every bending application an electrician will encounter.
Hand benders have become easier to use and more durable, and many large, high-production electrical benders can calculate layout measurements and make accurate bends in seconds.
“Tools for providing accurate head-down bends have evolved,” said Doug Eichner, Greenlee, vice president for engineering and product development. “Hand bender heads now feature cast-in markings for head-up bending as well as for producing stub-ups, offsets, saddle bends and back-to-back bends. The power pedal feature now has a larger foot area on the head for greater control, stability and leverage. Bender handles offer a bigger grip area, while still straight up and down for fast 30-degree bends. There also are strong, stable square hook designs, and with a choice of aluminum or iron alloy construction, this provides options depending on the user’s preference for feel and weight.”
Mechanical and hydraulic benders
Mechanical benders are a step up from hand benders, although human muscle power still provides the force. Bender components are mounted on a cart or carriage for easily rolling around job sites. Interchangeable shoes are used for various conduit types and sizes.
Hydraulic benders are used most often for rigid conduit or for conduits in sizes from 2 to 5 inches, which are too large for electric benders. They make smooth, round bends without conduit squeeze or bulge and without splitting pipe seams. Power for hydraulic pumps is provided manually or by electric pump motors.
Newer electric bender models on the market today have advanced programmable features and are ruggedly designed and built for use in the most demanding environments, said Greenlee’s Eichner.
“Electric benders are available today with absolute encoder-based control systems with an intuitive LCD user interface that allows users to easily program, save, transfer and recall multiple bends via a USB drive, making them invaluable for jobs that demand many types and high quantities of bends. Electric benders with these capabilities enable contractors to accomplish the most complicated bends with ease and speed,” he said.
For example, some models can bend -inch rigid and 1- to 2-inch rigid EMT or IMC conduit with just one shoe featuring patent-pending “smart” sensors that “know” exactly what diameter conduit and type is going to be bent and automatically factors spring-back for any angle.
Eichner pointed out that jobs containing bends with complex geometries tend to slow down productivity, waste material and create potentially awkward or unnecessary conduit configurations in the work area.
A key advantage with automated electric benders, he said, is the ability to accomplish any bend, including the most complex 3-D bends, with ease, all managed using the user-friendly and intelligent system. The same bend also can be replicated on other similar type benders.
“Electric benders with a control system that uses current-limiting technology is designed to draw the right amount of power which protects the motor and electronics,” Eichner said. “Combined with the absolute encoder-based system, an operator can increase repeatability and productivity while reducing waste of material.”
Electrical benders often come with a solid-state design that eliminates arcing and the potential of relay failure, Eichner said. The solid-state design helps increase the life of electronic components, while enabling the units to handle a variety of job site power sources, including generators and temporary drops.
“Mobility and flexibility also are enhanced with electric benders that are integrated with fork lift tubes, hoist bars, brake bars, adjustable handles and quick-release pivots for both vertical and tabletop bending orientations,” he said.
An increasing number of new benders come with the built-in combination shoes that will bend all 1- to 2-inch rigid, EMT and IMC conduit without additional accessories, Eichner said.
Heat is used to soften PVC conduit for bending. Heat boxes, tubes and blankets are the most common methods. However, in the past few years, new options have become available, including mechanical “cold” bending devices that do not require heat.
HotBend is a propane heat gun for bending or modifying existing bends in PVC, by heating the conduit with 1,200°F forced air. The hot-bending tool can bend PVC from to 8 inches in diameter and requires no electrical power or warm up, said HotBend Manager Chris Weggeland.
PVC Bendit markets a tool that heats plastic pipe from the inside, providing even heat over the length of the tool (3-, 6-, and 9-foot tools are available). The flexible, brushed, galvanized steel, electrically heated tool simply is inserted in a section of conduit, which is rotated during heating. Wearing gloves to protect hands from heated conduit, the required bend or bends are made by manually. The tool then is removed.
Blowing air into conduit speeds up cooling. Inventor Victor Johnson said the tool also can be used to bend acrylic tube and sheet materials, such as polycarbonate.
The Pipe Viper from Rack-a-Tiers is a spring that inserts inside rigid PVC to cold bend the conduit. With the spring inside the pipe, the user bends the conduit over a knee.
Benders marketed to electricians include models from these suppliers:
• Gardner Bender (www.gardnerbender.com) offers hand, mechanical, electric and hydraulic benders.
• Greenlee (www.greenlee.com) offers a complete line of benders and accessories that includes hand, mechanical, hydraulic, and sophisticated electric models and equipment to bend PVC pipe.
• HotBend (www.hotbend.com) offers a handheld propane heat gun for bending PVC pipe.
• Ideal Industries (www.idealindustries.com) markets ductile iron and aluminum hand benders.
• Klein Tools (www.kleintools.com) markets iron and aluminum hand bender heads and handles.
• PVC Bendit (www.pvcbendit.com) is a flexible, electrically heated tool that inserts inside plastic conduit to heat it internally for bending.
• Rack-a-Tiers (www.rack-a-tiers.com) sells a hand bender and “cold” spring PVC bender.
GRIFFIN, a construction and tools writer from Oklahoma City, can be reached at firstname.lastname@example.org.