Volume 14, Issue 3 - May/June 2012


Industry Professionals Discuss Pros and Cons
of Various Windshield Removal Technologies
by Sahely Mukerji

While suppliers might recommend one windshield removal technology over another, technicians seem to agree that many kinds of tools—cold knife blades, power tools and wire tools—are required for successful removal of windshields with minimal damage.

“I wouldn’t direct anyone to any one particular tool,” says Jeff Olive, training manager at Glasspro in Charleston, S.C. “Each device has its use and an experienced technician would realize the need for each tool. Each tool has its advantages, and you have to use each of them to become comfortable. ”

All three methods are necessary, says Robert Birkhauser, president of Aegis Tools International Inc. in Madison, Wis. “It depends on the actual removal and the part that you’re removing,” he says. “You need to have all three in your shop. Maybe use a cold knife near the A-pillars, and at the bottom use power tools.”

“There really isn’t a perfect tool, because cars have become more technical,” says Gilbert Gutierrez, vice president of Equalizer in Round Rock, Texas. “Technicians are having to use a greater arsenal of tools. All the tools come to play together. No one tool can do one car.”

Robert Nilsson, president of A.N. Designs Inc. in Torrington, Conn., agrees. Technicians use a combination of all the tools, powered or not, to remove glass from vehicles, he says. “Each one knows what is most comfortable for them,” he says.

Neil Duffy, owner of Auto Glass Menders in San Jose, Calif., agrees. “There’s a tool for every job,” he says. “I use all three. What tool I use depends on the kind of car I’m working on. The idea is to minimize collateral damage.”

Duffy likes cold knives. “I try to use a short blade to make cuts and use power tools at the bottom,” he says. “I have better control with the cold knife.”

A cold knife is the first thing that a technician will pull out of his toolbox, Gutierrez says. “It’s easy. You don’t have to plug it into the wall or anything,” he says. “Limitation of the cold knife is if the urethane is very thick and the windshield is too close to the pinchweld, it could scratch the paint. Then rust becomes a factor.”

Some manufacturers make edge protectors, such as Teflon coating on the edge, Gutierrez says. Some offer adjustable blades and pinchweld protectors.

Both power tools and cold knives have been used in the U.S. for many years, Olive says. “Cold knives and piano wire were the only tools available before 1985,” he says. “The manual piano wire—a handheld wire without the tool—was commonly used in the 1960s-1970s. It has existed for a long time, but wasn’t used much.”

Advantages and Disadvantages
Only 3 percent of the population has the upper body strength to lift a windshield, says Rick Nelson, product manager for Nelson Glass Tools in Garden Valley, Calif. “A National Institute for Occupational Safety and Health (NIOSH) report also calculated the strain ratio, and cold knives were rated at 5.1 and power tools were off the chart,” he says. “The scale was 1 through 5, with 5 bordering on injuries to upper back, shoulder, elbow and other parts of the body.”

However, a lot of the tests that are done on power tools are based on an 8-hour day, Gutierrez says. “You can get white knuckles if you use power tools for 8 straight hours,” he says. “No technician does that. Techs probably use the tools for 3 to 5 minutes per job. And if he’s using it in conjunction with other tools, he’s probably using it even less. You’d have to have hundreds of cars standing in line and a technician cutting their windshields one after the other to go eight hours.”

In a body shop, where a technician’s using a sanding board or jitterbugs or grinders, they use power tools on a longer basis. “And that’s where all these researches have been done, not in the auto glass industry,” Gutierrez says. “A chain saw will do the same thing if you use it for hours, it will. So will a snowmobile.”

Like power tools, strain is a factor when using cold knives, but many technicians prefer those because of their price and speed, Nilsson says. “Most technicians say it’s the most cost-effective and quickest method to remove a windshield,” he says. “With new designs including … interior and paint protection blades for special applications, they have become more than just a blade to cut the urethane around the windshield. Of course, a disadvantage of cutting with a cable knife is it’s a physical method, so keeping your tools sharp and using proper methods including an approved cutting lubricant is important to help reduce the strength needed. The blade shank thickness is an issue with certain vehicles due to the minimal roof-to-glass clearance. Some are narrower than the wire that is used.”

Cold knives require more physical strength than wire tools, Duffy says, and power tools can cause Carpal Tunnel Syndrome, “but it all depends on the technique,” he says. “I’m 6’2”, over 200 pounds, and I’m no winnie. I do a lot of removals in body shops. I use a lot of wires, too, but it takes more time to set it up. I’m a one-man outfit, and I do four to five windshields a day; I’m not doing eight. So, I can afford to take my time. You can take out a windshield in 10 minutes with a power tool.” Power tools are a great boon to saving time, Birkhauser says, but if used incorrectly, they can cause problems. “Power tools have vibration issues,” he says. “So, don’t operate the tools for long periods of time. Use the tools properly, don’t pull/push, and don’t use them in a hurry. Use vibration-dampening gloves” (see related box on page 24).

“We have 60 retail outlets and we use the Extractor tool,” says Alfie Ogston, regional manager at Crystal Glass/Extractor of Calgary, Alberta. “No tool will remove everything but the Extractor removes 90 percent of them.”

The other advantages of power tools are the reduced strength required to cut, Nilsson says. “Also they can easily remove glass without breaking it during cutout," he says. "Disadvantages that I can see are the price, and the damage that can be caused when not used properly. They are powerful and cut fast whether it’s urethane or something else in the way.”

The operator’s pre-disposition is also critical, Birkhauser says. “The size of the individual and how much strength they’re exerting are variables in sustaining injuries,” he says. “You really want to opt for a power tool when you can, but there are times when you need to use the manual cutout knife or the wire. Some have more pulleys, some need more physical strength to use. All good technicians are very particular about their tools.”

As with power tools, precautions can be taken when using cold knife blades, as well. “If you’re using a cold knife every day and pushing the glass out, bent like a pretzel, using your head, you will be guaranteed to have skeletal or muscular issues,” Birkhauser says.

With wire and cold knife, “you’ll want to wear cut-resistant gloves and safety glasses at all times,” Olive adds.

And of course, “if you eliminate sharp knives from the toolbox, there’s less chance of someone getting injured and paint damage on the vehicle,” Nelson adds.

Wire Tools
Wire tool technology has recently gained popularity in the U.S. It had its beginning across the pond, in the mid-1980s, when the Europeans developed the wire winding tool that pulls the wire static on one end with a steady tool, while the wire’s anchored in one place, Nelson says. “The old technique was putting a handle on each end of the wire and saw back and forth to cut through the urethane bead,” he says. “The wire tool eliminates the stress and strain on the removal system, and is a lot less stressful on the technician.”

The wire removal technology has been popular in Europe for many years, Olive says. “I see that it’s progressing in the U.S. because we’re seeing more flush-mount windshields, which means the pinchweld is exposed around the windshield, so the painted area around the windshield is exposed,” he says. “That makes the wire tools more popular. With power tools you’ll put a scratch here and there, but the wire tool will minimize scratches.”

They don’t allow any paint damage in Europe, according to Nelson. “They’re more strict than the Americans,” he says. “They have a different respect for the work area. The American market offers a range of products to cover up and eliminate paint damage and get it out as fast as you can. It adds time and materials to the job itself. The wire reduce the paint damage, if not eliminate.”

Wire seems to be a major player in the market due to the reasoning of the pinchweld becoming more exposed, agrees Gutierrez, but it is not the whole answer, either. “It’s not easy to accomplish removal without damage with the basic tools,” he says. “There are areas where you need help, and that’s where wire becomes a factor. Wires can be as thin as a business card, but they won’t cut through guide pins or stops.”

The other advantages of the wire tool are the reduced strength required to cut, Nilsson says. “The powered wire tools are hands-off other than guiding the wire during cutout, and the ratcheting tools require minimal input to operate,” he says. “They can remove glass without breaking it during cutout. Wire also offers the thinness cutting method from the outside. Small pinchweld-to-glass clearance is usually not a problem. The disadvantages I see are price, and speed of total removal.”

The wire tool is “like the sunrise coming over the horizon,” Nelson says. “Everybody knows that’s the way to go. The process will probably go with manual wire and then switch to power wire. We’ve been at it for four years, and we took it to Europe immediately and it caught up. We’re waiting for the U.S. to catch up. It’s been real slow, because of the recession mainly. The marketplace will embrace it.”

Down to the Wire
With windshields and vehicle aperture designs becoming more complex, the risk of technician injury or vehicle damage has increased significantly. These two points led one company to its windshield removal technology of choice and to roll this out nationally across the U.S.

Safelite AutoGlass has adopted a proprietary wire windshield removal tool. The company’s technical arm, Belron Technical, measured the actual physiological strains generated by the existing work methods, says Chris Davies, the head of technical research and innovation for Belron Technical in the U.K. “They measured muscular activity and the actual forces exerted on the tools in order to cut out the windshield,” he says. “With all of the existing, conventional tools, the forces and the muscular activity measured were extremely high showing that the risk of injury to the technician during their working career could be significant.”

A wire tool was subjected to the same ergonomic cutting force measurements as above. The chart above shows the reduction in cutting force exerted by a technician when using a wire tool as opposed to that needed when using conventional tools, Davies says. “The tool delivers a consistent cut irrespective of the vehicle model and bond quality,” he says. This means that using the tool reduces the risk of technician injury and the incidence of vehicle damage during the cut-out process.

Belron eventually chose a tool that uses less force than the aggregate per wire tools and handles, according to company officials.

Avoiding Carpal Tunnel Syndrome
Auto glass repair and replacement professionals agree that the key to avoid getting Carpal Tunnel Syndrome is to know how to correctly use a tool and always observe proper lifting techniques.

Other than the above, the following preventive measures are listed on the University of Maryland Medical Center’s website.
• No task should require the wrist to deviate from side to side or to remain flexed or highly extended for long periods.
• The handles of hand tools should be designed so that the force of the worker’s grip is distributed across the muscle between the base of the thumb and the little finger, not just in the center of the palm.
• People who need to hold tools for long periods of time should grip them as loosely as possible.
• In order to apply force appropriately, the ability to feel an object is extremely important. Tools with textured handles are helpful. • If possible, people should avoid working at low temperatures, which reduces sensation in hands and fingers.
• Power tools and machines should be designed to minimize vibrations.
• Wearing thick gloves, when possible, may lessen the shock transmitted to the hands and wrists. “Some preventative measures conflict with job performance, such as avoiding work in cold environments … but common sense can be invaluable when adapting work procedures,” says Robert R. Birkhauser, president of Aegis Tools International Inc. in Madison, Wis.

Sahely Mukerji is the editor of AGRR™ magazine. She can be reached at smukerji@glass.com. Follow her on Twitter @agrrmagazine and like AGRR magazine on Facebook to receive the latest updates.

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