The Struggle with Long Glass Kilns (And How We Fix It)
If you’ve ever run a tunnel kiln, you know the headache of cold spots. You need your temperature to climb steadily over a long distance, but standard short-wave lamps usually just aren’t long enough. You end up with these annoying gaps in heat that can ruin a piece. That’s why we build custom infrared units that stretch past 2 meters. It’s all about keeping that heat steady from start to finish. The Voltage Headache Here’s the thing: you can’t just stretch a quartz tube and call it a day. When a lamp gets that long, electrical resistance kicks in. If you aren’t careful, you’ll get a voltage drop right in the middle. The result? Your ends are screaming hot, but the center is barely lukewarm. We spend a lot of time balancing the filament load and tweaking the wattage. We make sure the middle of that 2-meter span hits the exact same temperature as the edges. No guesswork. Building it to Last When you’re dealing with lengths like this, gravity becomes an enemy. We use heavy-wall quartz tubing so the lamps don’t bow or sag under their own weight. We also lay them out in a continuous line. Why? Because we want to kill “striping.” You know those frustrating cold lines that show up on your glass during preheating? Those happen because of gaps. By eliminating the spaces between units, those lines disappear. Depending on what you’re making, you can go with clear quartz for deep penetration or coated tubes if you need to shift the heat spectrum. A Few Things to Watch Out For Installing these isn’t a “plug and play” situation. These arrays pull a lot of power. You’ll need to make sure your control panels can actually handle the total amperage, or you’re asking for trouble. And a word of warning: putting this much infrared power in a closed tunnel creates a massive amount of ambient heat. It gets hot. Really hot. If you don’t get your cooling fans and ventilation dialed in, you’ll fry your wiring and connectors. To help with the physical stress, we use reinforced end-caps. Kilns expand and contract as they heat up, and those caps keep the tubes from snapping when the metal moves.