Getting Long-Format Quartz Heaters Right in Tunnel Kilns
If you’re designing an infrared array for a massive glass tunnel kiln, you quickly realize that you can’t just take a standard tube and stretch it out. Once you cross that 2-meter mark, things get tricky. You start fighting physics—specifically voltage drops and the way materials stretch when they get hot. The struggle with power Here’s the thing about these long tubes: you can’t just pull the filament longer and call it a day. If you do, you’ll end up with cold spots at the ends or, even worse, a filament that burns out right in the middle because the voltage is too high. We spend a lot of time obsessing over the ohms per centimeter. It’s all about balance. You want that medium-wave heat to feel the same at the start of the tube as it does at the end. Just make sure your power supply is beefy enough to handle the whole row without popping a breaker the moment you flip the switch. Choosing the right materials We stick with high-purity quartz glass. It’s the only way to handle the shock of rapid heating and cooling without cracking. But there’s a catch. A 2-meter tube is basically a long piece of hot glass, and hot glass likes to sag. If you don’t support it properly, it’ll bow under its own weight. We usually suggest a tight support pitch. Keep it snug, or you’re going to have a messy problem on your hands. The real-world trade-off Putting these into a tunnel kiln is a bit of a gamble. On one hand, it’s great. Fewer tubes mean fewer electrical connections to wire up. It cleans up the build. But there’s a downside. If a 2-meter tube cracks, you’ve just lost a massive chunk of your heating zone in one go. It’s a big single point of failure. You have to decide if the easier wiring is worth the risk of a bigger headache during maintenance. One last tip: check your cooling fans. These units put out a ton of heat, and if the air around the mounts gets too stagnant, you’ll fry your wiring. Keep it cool, or you’ll be replacing more than just a tube.