Dealing with Thermal Dead Zones in Glassware
If you’ve ever worked with glass that has a weird shape—maybe a narrow neck, a flared rim, or some tricky internal bores—you know the struggle. You put it in a standard annealing kiln, but the heat just doesn’t want to go where it’s needed. We call these “thermal dead zones.” The problem is that air circulation just isn’t enough. It can’t push heat into those deep, recessed spots. That’s why we use targeted infrared (IR) lamps. They bridge that gap, making sure the whole piece hits the annealing point at the same time. No internal stress, no surprise cracks. Getting the heat where it actually goes Standard ambient heating is slow. IR lamps are different. They send out electromagnetic radiation that actually sinks into the glass surface. We pick lamps with wavelengths that the glass naturally absorbs. By setting them up in a multi-angle array, you can basically “aim” the heat at those awkward curves. You stop relying on the wind and start using light. It’s way more efficient. The gear you’ll actually need We usually go with high-wattage quartz halogen tubes. The quartz is tough as nails and won’t warp under extreme heat, and the halogen cycle keeps the filament from burning out too quickly. Your lamps will actually last. But here’s the thing: you have to match the wattage to the size of your vessel. A high-density lamp gets things hot fast, but it’ll pull a lot of power from your electrical panel. If you’re using a high-voltage setup to keep the current draw down, please, for the love of your shop, check your wiring. Don’t use cheap connectors. They’ll melt or oxidize the moment things start cycling, and that’s a headache you don’t want. The danger of going too fast IR lamps are fast. Really fast. And that’s where it gets risky. If you put a high-output lamp too close to a thin piece of glass, you’ll get “hot spots.” The glass can actually deform right in front of you. To stop that from happening, we suggest using a closed-loop PID controller paired with an infrared pyrometer. It lets you throttle the power as the glass gets close to the target temperature. It keeps everything balanced so you don’t accidentally cook one spot while the rest is still cold.