During the manufacture of Quartz Glass components, it’s often necessary to cut down the length of stock materials in preparation for additional processing. The most common method for quartz repairs cutting a rod or tube is to ‘snap cut’. This is a manual process, usually employed when the quantities required are small.
Snap cutting involves making a small scratch at the position to break. A compact diamond wheel cutter is sufficient to make the mark which doesn’t have to be completely around the circumference of the workpiece to be cut.
The purpose of the scratch is to fracture the surface and create a strain at the desired point. In preparation to snap the length, some Glassblowers may put a drop of water on the crack. The moisture has the effect of reducing the strength of the tube. Its just possible to see a small scratch mark towards left of centre on this tube.
QUARTZ GLASS CUTTING – IT’S ALL ABOUT TECHNIQUE
After the scratch mark is completed, the tube or rod is ready to be snapped. As we can see below, the craftsman firmly grips the tube at both ends.
The tube is then snapped using a combined pulling and bending operation. The experienced craftsman will know precisely the amount of force and pressure to apply to cleanly snap the tube. It’s all about his knowledge, experience and the workpiece dimensions to be snapped.
It literally takes a second to snap the tube as can be seen in this example.
Precautions must be taken to ensure that no injuries occur, the quartz tubing, or any quartz glass is extremely sharp until the edges are dressed and clean up. The snapped joint is surprisingly clean and straight.