Cutting Flat Glass: This is a demonstration of flat glass cutting done by a professional shop, it is not a “how to” article, as this is something that cannot usually be done by a novice.
Cutting Flat Glass: Safety glass is comprised of two identical layers bonded together with a laminate in the center. To cut it a diamond coated wheel lubricated with oil scores the glass by following the pattern. After scoring the top side it is turned over and the process repeated. The oil lubricates the cut and flushes away the glass shards as the pattern is traced.
Starting the cutline: Scoring the surface creates a stress line for the fracture in the glass to follow. The fracture is started at the edge of the glass pane with a special pair of pliers that have a high center anvil and two fingers that extend to the sides of the jaws ending below the height of the anvil. The anvil is placed on the centerline of the cut and when closed the fingers push down past center on each side creating the fracture along the cut line on both sides of the laminated glass.
Continuing the cutline: Once the fracture is started the striker on the other side of the special pliers is used to tap the glass along the cutline. This gentle tapping progresses along the cutline until a curve or deviation in the cutline is encountered.
Rounding the curve: Continuing the cutline around a curve is done with pliers with a flat smooth jaw. This requires a gentle touch and the patience to progress in short small segments as you round the corner.
Completing the cut: Once the fracture line is complete the laminate between the layers has to be cut. The temptation here is to breakaway the excess because the laminate is soft and can be pulled in-two relatively easy. This will stretch the laminate between the edges of the layers creating a separation around the edges of the glass. The proper way to cut the laminate is to soften it by squirting acetone or lighter fluid into the fracture line, lighting it with a cigarette lighter and then cutting the softened laminate with a razor blade or razor knife.
Finishing the edge: Tyler Phillis at Sanders Reproduction Glass uses this belt sander equipped with special guide rollers to create a true straight edge along the outside edge of the glass pane. Piece is compared to pattern as the finishing process proceeds to assure that the finished piece matches the pattern.
Polishing or beveling the edge: Trace Phillis at Sanders Reproduction Glass uses this high-tech polisher and beveller to finish the edge on glass calling for this treatment. Table at the left is a suction cup apparatus that holds the glass while the edge is finished by the abrasive stones in the machine at the right. A continuous water supply is fed into the cutter to cool the glass and clean away the debris during the process.
Stress-relieving the edge: Sharp edges on the glass create stress zones in the pane. Saucer-shaped chips along the edge like the one in the photo will eventually create a crack across the pane. When this occurs during the cutting process it is necessary to discard the piece and start over with a fresh pane of glass.
Sandblasted script: A small sandblaster is used to apply original manufacturers sandblasted script (logo and date, sometimes referred to as the "bug") duplicated to reproduce the OEM appearance. This is not necessary for hot rods or customs but needed on restoration projects.
Black edging: Early laminating processes were not as good as the current ones so the manufacturers used to coat the cut edges of the glass with a black sealer. That is no longer necessary but for an authentic restoration this little detail can add to the points earned in a competition