Fixing the “Cold Spot” Problem in Glass Tunnel Kilns
Most infrared lamps top out at one or two meters. That sounds like plenty until you’re running a massive glass tunnel kiln. When you string those shorter lamps together, you get these tiny gaps—little dead zones where the heat just drops off. It sounds minor, but it’s a nightmare. Those cold spots cause the glass to expand unevenly, and suddenly, your glass is cracking during the cutting process. It’s frustrating and expensive. That’s why we build custom heating units that push way past that 2-meter mark. The headache of long tubes You can’t just stretch a piece of quartz and call it a day. If you do, you’ll run into voltage drops and current spikes. Here’s the thing: if the power isn’t balanced perfectly from end to end, you get “hot spots” in the middle and “cold ends” near the connectors. Your preheating profile goes right out the window. We spend a lot of time dialing in the wattage and voltage so the heat stays steady. Every single centimeter needs to pull its weight. Picking the right gear We stick with high-purity quartz because it can actually handle the thermal stress without giving up. But the real secret is in the layout. Instead of a modular setup with gaps, we overlap the lamps. It creates a solid wall of heat. Depending on how deep you need that heat to soak into the glass slab, you can go with short-wave or medium-wave emitters. Both work, but they feel different depending on your specific glass. A word of warning on installation These units are beasts. Because they put out so much energy in one spot, the wiring has to be heavy-duty. And be careful with your kiln’s chassis. This much heat is brutal on the hardware. If your cooling fans aren’t up to the task or your venting is clogged, the housing will overheat and your connectors will literally burn out. Keep the airflow moving. It’s the only way to keep the system from eating itself.