Laminated Glass Cutting – Equipment and Handling

When I first ventured out with my own company, I formed a partnership with a local glazing company in my hometown. They did flat glass, storefronts and shower doors, and I was able to add auto glass to their business offerings. Early in our partnership, a tempered tractor windshield came in and I was asked to install it into the frame. I asked my partner why they had ordered this piece tempered rather than cutting it from laminated safety glass. He told me their policy had been not cut laminated glass because they never had success fabricating parts without breaking or chipping the glass. My partner was a professional glass cutter with 40 years of experience and 30 years of shop ownership. It surprised me that he would rather pay more for a part than fabricate it from laminated glass. To make matters worse, the part they had ordered was too big and had to be re-cut and tempered. Lesson learned: make sure of your pattern and measure twice, cut once. But there was another lesson here as well. If they had cut the part from laminated safety glass the part would have been much cheaper and the glass, if cut wrong, could be adjusted and installed rather than re-cut and sent out for tempering.

So, let’s learn how to cut laminated safety glass.

First you need the tools and equipment to cut the glass efficiently and safely. You will need:

  • A cutting table, either homemade or professionally manufactured (To comfortably cut the tractor windshields and larger parts I suggest you get a 4’ x 8’ table.)
  • Straight edge and square
  • Clamps
  • Glass cutters, self-oilers or disposable cutters work fine
  • Oil
  • Marker or wax pencil.
  • Glass pliers, I prefer drop-jaw pliers but any glass pliers will work
  • Lamination cutter, I like an old tape measure blade but a single edge razor blade will work too
  • Edgers, manual or power depending on budget and frequency of use
  • Leather apron, safety glasses and glass handling gloves for safety

Next, you will need the glass. Laminated safety glass usually comes in two thicknesses which are determined by the thickness of the laminate, .015″ (1.5mm) sometimes referred to as “sheet” and .030″ (3mm) called “plate.” The plate glass is graded AS1 glass while the sheet glass is graded AS2. You would use the sheet for uses other than windshield applications and the plate for the windshield.

Handling the glass properly is very important for the success of fabricating a part. Before cutting the glass, make sure that it is at room temperature (65⁰F – 80⁰F). If the glass is too cold or too warm you will limit your chance of success. Most glass used for auto glass fabrication is of a smaller block size and can be handled by one man. However, if a large part is needed for off-road equipment or a tractor, a second man or a glass trolley may be needed to transport or handle the glass. Before placing the glass on the cutting table, clean the surface completely. Small chips or slivers can scratch or damage the glass even before beginning the cutting process. If you are placing a large glass sheet on a cutting table, place the back surface of the glass on the table’s edge and pivot the glass down onto the table. This assures that the glass will not prematurely fracture while it is being manipulated on the table.

laminated glass Word Image

Once the glass is positioned on the table and cleaned, the next step is to add the pattern to map out the cutting. Next week we will look at the process of prepping the glass for fabrication so the cut will be accurate and smooth.