Learning how to cut glass into complex shapes or patterns requires a certain level of skill and application. You can cut glass in curves with some practice although you need to be careful and have a steady hand. It's also very important to focus on safety as broken glass is incredibly dangerous. Always handle glass with gloves on your hands and wear safety glasses to protect your eyes.
Step 1 - Mark the Curve
To start, you need to use the marker to draw your curve on the piece of glass you’ll be cutting. It’s important that each curve is no longer than 6 inches in length since longer curves can prove very problematic.
You also need to decide what kind of glass cutter to use. There are two choices: you can use either a wheel type cutter or a diamond-tipped alternative. Either one will do the job well. You will need to establish a tight grip on your chosen tool and apply it firmly to the glass in order to exert the correct pressure. It’s best to practice cutting on spare pieces of glass until you feel comfortable using the tool.
Step 2 - Cut
There’s a definite art to cutting glass. It has to be done in a single, smooth stroke along the required cutting line and it can be done by either pulling or pushing the cutter. The sound of the cutter on the glass should be crisp so you know you’re making an effective cut. At the end of the glass, you need to slide the cutter off without letting up on the pressure.
To cut glass in a curve, you’ll need to do it freehand by following the marker line you’ve made on the glass. Once you start, don’t stop until you’ve finished the entire line.
Step 3 - Break the Glass
To break the glass, set it on a table so the scribed line is over the edge. From underneath, tap along the line with the handle of the glass cutter. A crack should appear along the line you’ve cut. Now, hold the glass so the edge is on the table and you’re holding the edges with your hands. Pull the two pieces apart. If you’ve cut well, the glass should come apart easily
Step 4 - Do Longer Curved Lines
If you want longer curved lines, do so by making a straight cut first. Do this by running the glass cutter in a straight line along a metal straight edge on the glass but remember to leave room for the curve. Remove the excess glass. Mark the curve with a marker. Again, each curved section should not be longer then 6 inches in length. Use the cutter to cut glass in the curve. Hold the larger piece of glass in your hand and grasp the piece to be removed with pliers. Pull down on the pliers sharply to finish the cut.
Work piece by piece along the glass, cutting straight lines and then cutting and removing the curves until you have the full curve of cut glass complete. The edges should be reasonably clean. If they’re not, you can file them lightly with a whetstone until they’re perfectly formed.