Stop the Cracks: Getting Your Glass Annealing Right
Anyone who’s spent time bending lab glass knows that feeling. You’ve spent hours shaping a piece, it looks perfect, and then—snap. It’s frustrating. Usually, it happens because of internal stress. When you heat and shape glass, it holds onto that tension. If you don’t bleed that stress out slowly and carefully, the glass just gives up. That’s why hitting your temperature exactly—down to 0.1°C—actually matters. Why regular heaters fail you Here’s the thing: glass is stubborn. It doesn’t heat up evenly. If you use a standard heater, you end up with “hot spots.” Some parts of the glass expand faster than others, and that’s a recipe for disaster. We use shortwave infrared instead. It doesn’t just warm the air around the glass; it actually penetrates the surface. By keeping the temperature locked in at a 0.1°C tolerance, we make sure the core and the exterior cool down together. No sudden shocks, no structural failure. Just a stable piece of glass. The guts of the system To make this work, we pair high-density IR lamps with PID controllers. Speed is everything here. The second a sensor picks up a tiny 0.1°C drift, the power has to adjust. Right then. We usually go with quartz-halogen elements because they ramp up and down incredibly fast. One quick tip, though: these IR arrays put out a lot of waste heat. If your ventilation isn’t pulling that heat away from the electronics, your sensors will start to drift. And once that happens, you lose that precision you worked so hard for. Bringing it to the shop floor You don’t need to rip out your entire setup. We designed these heaters to just drop right into your old, clunky ovens. instead of heating the whole room, you can use zoned IR to target just the flask or tube you’re working on. It’s a huge time saver. You get a stress-free part without having to let it sit in a lehr oven for six hours. Just wire it up to a precision SCR, dial in your profile for borosilicate or quartz, and you’re good to go.