Stop the Cracks: How to Nail Your Glass Tempering
If you’ve ever worked with glassware, you know that transition to tempering is a nerve-wracking part of the process. You need a sudden spike of heat, but it has to be just right. If you’re too slow, or if the heat hits unevenly, you’ll hear that dreaded snap. Your piece is ruined. That’s why we rely on shortwave quartz infrared (IR) lamps. They give us the kind of “instant” heat control that keeps the glass from shocking and shattering. Getting the heat density right To keep glass from exploding, your heater needs to be able to ramp up and down in milliseconds. We use quartz lamps with high wattage density because they can handle that kind of stress. But the real secret is pairing them with SCR power controllers. This lets you tweak the heat output in real-time. It stops the surface of the glass from expanding way faster than the core, which is usually where things go wrong. If your power supply isn’t perfectly tuned to the lamp, you’ll get hot spots. And hot spots mean scrap. Why quartz? We stick with high-purity quartz tubing for a simple reason: it gets out of the way. It lets shortwave IR radiation pass right through without soaking it up. Instead of wasting energy heating up the air around the glass, the heat hits the surface directly. These emitters react way faster than the longwave stuff. You can flick them on and off almost instantly. That speed is what allows us to hit the glass with exactly the right amount of energy to create that compressive stress layer. Fitting them in The good news is these lamps are basically drop-in replacements for standard IR arrays. We spend a lot of time on the filament alignment because a uniform heat footprint is everything. Just a heads-up, though. These high-wattage lamps pull a lot of juice. They put a serious load on your wiring. Make sure your cables and connectors can handle the peak current, or you’ll be dealing with burn outs during your rapid cycles. Not a fun way to spend a Tuesday.