How to Stop Your Glass From Cracking During Tempering
If you’ve ever worked with quartz or glassware, you know the nightmare of the cooling phase. It’s where most of your hard work ends up in the scrap bin. One minute everything looks great, and the next—snap. Usually, it happens because the glass gets hit with a wall of heat or cooled down too aggressively. That internal stress is a killer. To fix this, we lean on short-wave infrared (IR) lamps. Unlike those clunky convection ovens that take forever to react, these lamps let you tweak the power in milliseconds. You get actual control over the temperature, which is the only way to keep the glass happy. Getting the heat right, right now To avoid thermal shock, your system can’t lag. It needs to ramp up and down instantly. We use IR lamps with high power density so the surface hits tempering temps the second it needs to. Pair these with SCR controllers, and you can basically throttle the wattage in real-time. It stops those dreaded “cold spots” that usually shatter thin-walled quartz tubes while you’re reheating them. It’s a huge relief not having to hold your breath every time a piece goes through. Why the lamp design actually matters We stick with quartz envelopes for the heating elements because they don’t hold onto heat. They just radiate it. Think of it like this: the moment you kill the power, the heat stops. If you use a heavy metal heater, it keeps pumping heat into the glass long after you’ve told it to stop. That’s how you end up with deformed pieces and a lot of frustration. A few things to watch out for Now, high-wattage IR arrays are fast—which is great for keeping the line moving—but they’re hungry. You’ve got to make sure your power supply can actually handle those peak current spikes during rapid cycling. And here is a pro tip:Keep your lamps clean. Seriously. A single fingerprint or a smudge of oil on the quartz envelope creates a hot spot. That hot spot will eat through the lamp, and it’ll burn out way faster than it should. Keep them spotless, or you’ll be replacing tubes a lot more often than you’d like.