by Bob Beranek
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A few months ago at Auto Glass University in Michigan I had a conversation with one of my students regarding cutting auto glass versus buying it pre-cut. I think it’s becoming a lost art. Cutting laminated glass is a challenge not many professionals pursue since most parts can be purchased pre-cut. However, cutting your own laminated parts can put a few more dollars in your pocket if you have the equipment and time.

In the past I’ve written about some of the techniques used to cut laminated glass and I urge you to look back for more information if you’re interested. Nevertheless, I have not examined the most important tool in glass fabrication, the glass cutter itself. There is more to a glass cutter than you might think.

There is an assortment of glass cutters that each have characteristics that appeal to the glass fabricator. You can choose between:

  • The type of handle;
  • The type of head;
  • The cutting wheel composition;
  • The wheel hone angle; and
  • Self-oiling.

Type of Handle

Pencil Grip – Photo Courtesy Home Depot

Pistol Grip – Photo Courtesy Delphi Glass

There are two types of handles: pencil grip and pistol grip. The pencil grip requires about 2-5 lbs. of finger pressure, while the pistol grip requires the same amount of pressure but requires more hand pressure versus finger pressure. The type of grip depends on the cutter’s preference.

Type of Head

Pattern Cutting – Photo Courtesy AliExpress.com

Straight Cutting – Photo Courtesy Equalizer

There are two types of cutting heads: straight cutting and pattern cutting. The pattern cutting head is narrower and swivels 360 degrees. Meanwhile, the straight cutting head is wider and does not pivot. Though auto glass technicians cut from patterns, most cuts are straight, making the straight cut head preferred.

Cutting Wheel Composition

Most glass cutting wheels are made of steel because it’s the most economical, but they dull faster. The tungsten carbide wheel is another option. If you plan on cutting a large amount, the tungsten carbide wheel is the head of choice.

Wheel Hone Angle

The hone angle for most cutters ranges between 120 degrees – 154 degrees, the higher the number the sharper the wheel. A cutter with a 154 degree hone angle is recommended for glass over ½-inch thick. Auto glass cutters never cut glass this thick, so the lower hone angles are recommended.

Self-oiling Cutters

Oil’s purpose in glass cutting is to lubricate the cutting wheel for smooth scores. Some cutters have a reservoir built into the handle for oil to be dispensed. These are exceptional cutters, but if dry cutters are stored in oil, a less expensive cutter can be used with excellent results.

Photo Courtesy Amazon.com

Photo Courtesy Equalizer

Glass cutters are rarely sharpened, using it hones it and keeps it in “round.” The end of a glass cutter is when the wheel goes out of its “round” shape. If a glass cutter is dropped on the floor it, or at least the head must be replaced. A burr in the wheel will cause the cutter to skip and cause the glass to erratically break.

Consider adding glass fabrication to your area of expertise. With a little practice, it can bring big dividends.

In my last post, I mentioned a discussion I had with one of my students, regarding adding laminated glass cutting as an additional service and profit booster. We talked about the glass cutter and its options. This post addresses an equally important item for glass fabrication, the cutting table or surface.

The cutting surface is an important piece of equipment for successful glass fabrication. If your plan calls for a large amount of fabrication, a professionally designed table is recommended. These tables can cost up to $6,000 with many features to choose from. However, if you plan to fabricate a small number of parts weekly or monthly, you can build your own for a fraction of the cost.

A homemade cutting table starts with a supporting frame, which reduces the chance of warping.  A good-sized table is 4 feet by 8 feet, build a frame with two 2×4 inch by 8-foot boards on the long side and two 2×4 inch 4-foot boards on the short side. Then, support the frame with two center boards evenly spaced between the two short ends and nail all ends together. It may be a good idea to dove-tail or screw and glue the connections together for a long-lasting joint.

For the top, take one-4 foot by 8 foot by ¾ inch piece of particle board and one-4 foot by 8 foot by ¾ inch piece of plywood and glue and screw them together. The plywood should be the top surface and the particle board should be the underside. Use a generous number of 1-1/4-inch flathead wood screws and a liberal amount of carpenter’s glue to attach the particle board to the plywood. It’s a good idea to drive the screws from the underside into the top.

Mount the top to the frame with 2-1/2-inch or 3-inch flathead wood screws and carpenter’s glue. Drive the screws from the top and countersink. Place the screws in the corners and evenly space them along the perimeter of the frame and the center supports. Fill any of the countersunk divots in with wood filler.

Cover the top with an indoor-outdoor carpet once the wood filler is dry. Make sure the color you choose will not hinder the visibility of a broken score. The most popular colors on professional tables are green or gray. Attach the carpet to the side of the frame with screws and large washers and stretch the carpet as tight as possible. Then attach the carpet to the opposite side and repeat on the remaining sides. The beauty of this carpet attachment is that it can be replaced easily when worn or tightened when necessary.

Place the finished top onto a sturdy base and you have a cutting table that should last you years.

This simple design can also be downsized for mobile use (4ft. X 4ft.) or adapted to any mounting. One shop mounted it on a wall with hinges and stored it there when not in use.

Good luck and happy cutting.

Recently we’ve seen an increase in questions on the Auto Glass Safety Council (AGSC) Master Certification and requests for more study materials for the exam. Master certification is different from the Technician or General exam because it tests more advanced services usually offered by the full-service auto glass shops. These services can include:

  • An in depth understanding of regulations and standards pertaining to our industry,
  • Safety related issues and OSHA regulations for the work place,
  • Laminated glass fabrication (glass cutting and finishing),
  • Pattern-making and template construction,
  • Older and more unique vehicle glass replacement, and
  • Understanding electrical circuits and troubleshooting those circuits.

Though information on some of these subjects is harder to find than others, I thought I would begin this series of “Master” posts with the most common electrical problem a glass shops see – rear window defroster malfunction.

There are three defroster malfunctions that present themselves to the customer; either the defroster does not work at all, one or more gridlines do not work, or the defroster connectors come off. Let’s address each of these.

  1. If the defroster does not work at all, it means that power is not getting to the unit. First, you should check the fuse. If the fuse is blown, replace it and make a suggestion to the owner that they get the system checked by the dealer. A blown fuse means there’s something wrong with the system. The system (circuit) consists of:
  • The power source (battery),
  • The wiring from the battery to the fuse block,
  • The wiring to the switch,
  • The wiring from the switch to the connectors on the defroster,
  • The connectors on the defroster both the incoming power and the ground, and
  • The defroster grid itself (Unit).

Replacing the fuse is a short-term fix.  If you’re able to trace the problem to its source, do so. However, if you do not have the expertise to diagnose and fix the problem’s cause, I suggest you refer the customer back to the dealer.

Photo Courtesy Main Image – Ebay

 

  1. The customer comes in and complains that one or more of the lines are not working. This usually indicates that the grid line(s) is severed and must be repaired.

How do you find the break in the lines and how do you fix it?

You will need a defroster repair kit from your local hardware or auto parts store. It will consist of a small jar of metallic paint, a brush and a template. You’ll need an ohmmeter, which uses an outside source of power for its reading, not a test light. A test light uses the power supplied in the circuit to light the bulb in the tool.  This adds another unit to the circuit and could confuse the internal computer of the added unit and cause further problems.

Turn the vehicle on and connect the ground lead of the ohmmeter to the defroster’s ground connector, this is usually on the passenger side of the back glass. Now take the power lead and gently drag the lead along the suspected grid line. A properly operating grid line would have a slowly decreasing volt reading from 12 volts to 0 as you move the lead from power side to ground side. A broken line would have a consistent 12 volt reading until it suddenly drops to 0. When the voltage drops to zero suddenly, that is where the break in the line is located. Mark the break point and attach the template to its location. Then paint a “bridge” across the two ends of the line with the metallic paint and allow to dry thoroughly. Retest and confirm repair.

  1. The connector tabs frequently break off of the bus bars due to cleaning the inside surface of the back glass or from items stored on the back shelf or storage area. There are several products that do an excellent job of reattaching the tabs and reestablishing the electrical circuit. However, there’s another way that has proven results.

You can simply use a cyanoacrylate glue, such as Super Glue, to reattach the connectors to the glass surface at the point of separation. Then use the defroster metallic paint to make the electrical connection between all circuit components. The circuit components are the connector, the bus bar above the separation point, and the bus bar below the separation point. This will join all of the components and reestablishes the circuit. Then allow the metallic paint to dry thoroughly and test the repair.

Caution:  Do not add concentrated heat to a particular point, such as a solder gun. This could cause a thermal break.

I’ll give you more information concerning the tested knowledge in The AGSC Master’s Certification exam in future posts. My “Lost Arts” series of posts cover the laminated glass fabrication and finishing and can also help when studying for the exam. Please contact me if you have any other questions about Master Certification.