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Taking the Pain Out of Glass

These days, automotive glass serves a bigger purpose than simply keeping bugs out of a driver’s teeth. Some passenger-side airbags depend on the windshield to act as an integral part of the system. With such a critical repair at hand, proper glass replacement is of the utmost importance — but isn’t nearly as complex as you might think.

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Writer Mike West, a contributing editor to BodyShop Business, retired and closed his shop in Seattle, Wash., on July 1, 2011, after more than 40 years in collision repair. The mayor of Tukwila declared that day “Mike West Day” to honor West for his 39 years as a businessman in the city. He is keeping active by restoring a 1933 Rockne Sedan Delivery and a 1934 Pierce-Arrow Rumble Seat Coupe. He plans to continue administering the I-CAR in-shop welding series in the Western Washington area.

There seems to be a lot of silence in the collision repair industry when it comes to glass work. You see very few articles in trade magazines or papers that address the issues and importance of glass as part of our industry. Why?

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One reason is the shrinking number of collision repairers who do their own glass work. And one of the major reasons glass work became a sublet item was that the insurance industry started requesting that repairers allow glass companies to come in the shops to perform glass work on site. Cost reduction was the prime purpose behind this tactic.

Glass shops were in a better position to offer insurers a larger discount because of their close ties to the aftermarket glass manufacturer. Glass shops generally have lower labor costs than collision repairers, as well. If work is done on someone else’s premises, your overhead will be significantly lower than if you had to pay for heat, lights, water, sewer and taxes for a facility large enough to handle the work you do. Lower overhead equals a deeper discount.

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Do I do my own glass work in my shop? Yes.

I own the shop and I pay the overhead; therefore I control what happens inside the building. This basic principle was a deciding factor for me. Why would I allow someone else to come into my shop and use my facilities and utilities to conduct their business? Additionally, I’d carry the liability for the quality of work, the inherent safety issues, the quality of the glass and the materials used for the job. My decision was to continue controlling and doing what I believed was right for my customers and my business.

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I’ve had no major problem with any insurer. I make the same profit on glass as I do on any part, and I like to do glass work because, generally, gross profit per labor hour is higher thanks to the price of glass. I also control the quality of glass used, the materials and the quality of workmanship.

More Than a Window
Why is proper glass replacement so important within our industry?

As the cost of fuel rose to new highs in the early ’70s — brought on by the oil shortages — the federal government mandated that more fuel-efficient vehicles be manufactured. Hence, the production of the lighter, more fuel efficient unibody car.

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"So what’s that have to do with glass work," you ask?

Everything! It’s actually the basis of the transition we’ve seen take place in our industry, since the mass production of the unibody vehicle began. Of course, part of that transition involves the way glass is now used, removed and installed to meet Federal Safety Standards.

When the auto manufacturers began producing lighter vehicles to promote better fuel efficiency, glass became more and more of a structural component. It was no longer just something to look through.

Federal regulations then mandated specific structural strength requirements for the adhesives used to bond glass to the vehicle. This increased the complexity and the liability involving the performance of glass work.

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These days, some passenger-side top-mounted airbags depend upon the windshield to act as an integral part of the deployment system. The windshield deflects the airbag toward the passenger upon deployment, so it’s imperative the windshield not be pushed out of the opening, or the system won’t work properly. Because this type of system exerts incredible force against the windshield, proper replacement technique is crucial.

As such technical issues began to emerge, many shops opted to sublet their glass work. That took care of the complexity issues, but not the liability issues. Shops that sublet are still ultimately responsible for any liability that may arise from improperly installed glass.

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What’s that mean? It means if your customer’s passenger is launched through the windshield opening in a frontal collision, you may be liable — regardless of whether you sublet the windshield replacement or did it yourself. Why? Because you were entrusted with the repair of the vehicle, so you’re responsible for any substandard repairs that occur during the repair process — suspension alignments, airbags, electrical, mechanical or glass.

"Well hell," you say, "that’s why I sublet it in the first place. To let an expert do it."

OK, I can follow that logic, but we all know the "expert" is somewhat subjective and dependent upon the attitude and policy of management, training, skill level, pay method, etc. These are all things you have little control over in another person’s company.

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Feeling a little vulnerable? You should!

Ever seen glass that was improperly installed? I’m certain you have. We’ve all seen it.

Whether you perform your glass work in house or sublet it, your knowledge of what constitutes a proper repair is of the utmost importance. Your ability to recognize improper methods and techniques is at least as important with glass as with any other repair procedures.

Scary? It doesn’t have to be if you get involved, become informed and gain control of the repair. (You’d better be in control of the repair. After all, your customer has entrusted his safety and well-being to you.)

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Having said that, I’ll try to educate you as to what you’ll need to know to perform and recognize a proper repair.

Glass Removal
What qualifies me to write about glass? I’m an ASE-certified Master autobody repair/refinish technician with 37 years experience, and I’ve owned and operated my own collision repair business for 28 years. We’re an I-CAR Gold Class shop, an ASE Blue Seal of Excellence facility and we perform our own glass work.

To me, much ado about nothing has been made regarding the removal of glass, specifically bonded glass (what this article refers to). With the power tools available today, removal of glass is much easier than it used to be. Yes, some skill is necessary, but it’s easily learned if you’re cautious and you focus.

With that said, let’s get started:
Be aware of the black "frit" band that you see on bonded glass. The purpose of this frit is to provide an ultraviolet screen for the urethane adhesive. This prevents the sun from deteriorating the urethane, which was a very common problem in early bonded glass.

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I always use the long-cut method, which refers to where you cut the urethane bead (close to the glass or close cut, or close to the pinch weld or long cut). I use the long-cut method because most OEs that recommend a procedure recommend long cut.

• Step 1: Cut the urethane adhesive from inside the vehicle. I use two different power knives when removing a windshield. Both are air operated. One uses a long sheath enclosed blade that’s thin and looks like a hacksaw blade without teeth. This works well along the bottom and protects the dash while cutting the bottom bead. The other cutter uses different knife blades and works well for the top, side cuts and final trimming,

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It’s a must to keep these blades sharp. The sharper the blade, the easier the work. I don’t hand hone my blades. Instead, I use a metal polishing wheel and stainless compound to bring them to a fine razor-sharp edge. It takes about three minutes to do both blades.

• Step 2: Put some soapy water in a squirt bottle and lubricate the cut area. (Many auto glass workers use water from a squirt bottle as a lubricant when cutting urethane. Installers argue that soapy water can leave a residue on the base for the close-cut method, but this isn’t an issue if you trim out the old urethane later.)

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• Step 3: Let the knife do the work. Don’t force the cut, and be aware of what you’re cutting — metal, glass or urethane. Use your ears and your sense of feel to determine this.

• Step 4: Remove the glass. Most side glass and back glass come out nicely because they’re tempered and resistant to pressure breaking. (I’ve even used light pressure with the rubber aft end of a 4-ton porto power to apply pressure when cutting the urethane. This works best on side glass. I’ve never broken one yet.) Windshields are difficult to remove without breaking because they’re safety glass and subject to stress cracks or runs (splits) from nicking glass with your blade. Be patient. Most glass can be removed successfully in 15 to 25 minutes, plus all trim and cleanup time.

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The windshield breakage issue is rare because most are removed because they’re broken anyway and are replaced as part of the repair. If you need to remove an unbroken windshield to facilitate a repair, inform all parties involved of the possibility of breakage during removal. I’ve found that most adjusters appreciate the warning and are willing to cover the cost of replacement if breakage occurs. Be upfront.

Glass Installation
If you’re re-installing the glass, inspect it for "frit" damage. I’ve touched up minor nicks to the inside with black urethane pinch weld primer. It sticks to the glass well and blends into the surrounding black frit.

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I don’t trim the glass or the pinch weld at this time. I don’t want to expose the urethane base to any pollution like dust, grindings, overspray, masking tape gum, etc. Urethane sticks best to urethane, so I want a freshly cut base just before I apply my new urethane adhesive. I do all of my repair work and painting prior to setting the glass. Immediately before setting the glass, I wash the inside of the glass to prevent pollution of the base and then trim the old urethane from both the glass and the pinch weld.

If there are any nicks in the pinch weld after trimming, touch up the nicks only with urethane pinch-weld primer. Don’t use this on the entire pinch weld. Remember: Urethane sticks best to urethane.

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I use a 6 mm square foam dam tape on the inside edge of the pinch weld. This serves two purposes: One, it provides a dam to prevent unsightly gooey urethane from entering the passenger compartment. And two, it allows the urethane to cure. There are two ways to cure urethane: moisture and heat or warm air. The foam dam allows warm air and humidity to enter the urethane from inside the passenger compartment.

Urethane doesn’t cure well inside the tube, does it? And if you use a butyl tape dam or the close-cut method, you create an airtight enclosure when you put the molding on the outside, much like the tube the urethane came out of. It’s well-sealed in that cavity and can remain uncured. Use foam dam tape instead, and make sure you have at least 6 mm to apply the adhesive.

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Now you’re ready to apply the urethane adhesive. (Choose a urethane from your supplier that’s ideal for your shop conditions.) Preparation of the tube tip is very important. I cut it at a 45-degree angle, far enough back toward the tube so I have no less than a 1/4-inch diameter opening. I then V-notch the tip about 3/8 to 1/2 inch on the long side of the tip. This allows me to apply the urethane to the pinch weld in a beautiful even bead, which will compress into a strong even bead that won’t leak.

I use a quality caulking gun powered by me, but with the greatest squeeze ratio available. This gives me the control I need to apply an even bead. Keep practicing and you’ll do fine.

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Now, I set the glass. I use suction cups, but you don’t have to. My goal is to never touch the fresh urethane because that makes a mess. Notice I said that’s my goal — and sometimes I even succeed. Take your time and set the glass properly into the opening. If it’s a windshield or backglass, make sure it sets properly on the rests at the bottom. Press in evenly, ensuring a seal all the way around. Inspect the edge carefully. If necessary, backfill a little with a tip cut for a small bead.

Before the urethane begins to set, apply the molding. If you apply a new molding for the windshield or back glass and it’s the flexible "tree" type, place it in a bucket of hot water to decrease rigidity. This works beautifully.

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You’re almost done!

Roll down the door glass to prevent disturbing the "set" as the urethane cures. Shutting the doors with the windows closed will cause outward pressure and possible leaks. Allow proper cure time, and you’re ready to roll.

Glass Doesn’t Have to Be a Pain in the !*@#!
There’s no mystery to proper glass work. By using consistent, recognized techniques, and quality tools and materials, you’ll produce an outstanding, safe repair — and a tidy little profit for your shop.

Writer Mike West, a contributing editor to BodyShop Business, has been a shop owner for the past 28 years and a technician for 37 years. His shop in Seattle, Wash., has attained the I-CAR Gold Class distinction and the ASE Blue Seal of Excellence.

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