Dealing with those annoying “dead zones” in glass annealing
Ever had a piece of glassware look perfect, only to have it shatter out of nowhere? It’s a nightmare. Usually, it happens because of “dead zones.” When you’re working with weird shapes—think narrow necks or deep, chunky bases—standard convection heat just doesn’t cut it. The heat misses the tight spots. The glass doesn’t soak evenly, internal stress builds up, and then… crack. We fix this by using targeted short-wave infrared (IR) lamps. Basically, we stop hoping the air carries the heat and just beam it exactly where it needs to go. Getting the heat to actually hit the glass Here is the thing: you can’t just crank the dial to eleven and hope for the best. That’s a great way to ruin a piece. It’s all about the angle. We use a multi-angle array of lamps to essentially “wrap” the heat around the vessel. Short-wave IR is great because it actually penetrates the glass rather than just bouncing off the surface. It pushes energy into those deep recesses where air-based heating usually gives up. The balancing act: Distance vs. Heat Placement is a bit of a tightrope walk. If you put the lamp too close, you get “hot spots.” The glass can warp or deform before you even realize what happened. But if you push them too far back? You’re wasting power and your annealing cycle takes forever. We usually figure out the sweet spot by looking at the wattage per centimeter of the lamp. It’s all about finding that middle ground where the temperature stays smooth across the whole piece. A few tips for the setup If you’re wiring this up, be careful with your controllers. IR lamps are fast. Like, really fast. Unlike those old resistive elements that take a while to warm up, IR hits the target almost instantly. You’ll want a precise PID loop, otherwise, you’ll overshoot your temperature and end up with a mess. And one last thing—these arrays put out a lot of waste heat. Make sure your kiln’s ventilation can handle the extra load, or you’re just turning your workshop into a sauna.