Fixing the “Cold Spot” Problem in Glass Tunnel Kilns
Most infrared lamps stop at about a meter. That’s fine for small jobs, but if you’re running a glass tunnel kiln that needs a steady heat zone over two meters, you’ve got a problem. Standard lamps leave gaps. Those little cold spots might not seem like a big deal, but they lead to uneven curing and—worst of all—warped glass. It’s frustrating. That’s why we build custom twin-tube infrared units. We basically make them long enough to cover your entire layout in one go. The tricky part: Power. You can’t just stretch a piece of quartz and call it a day. The longer the tube, the higher the electrical resistance. If you don’t get the math right, you’ll either blow a circuit or end up with a lamp that’s hot at the ends and lukewarm in the middle. We spend a lot of time dialing in the voltage and wattage to fit your specific Power grid. Usually, we go with a higher voltage setup to keep the heat steady from one end to the other. Just a heads-up: make sure your power supply can handle that initial surge when these things kick on. It’s a lot of energy hitting at once. Why two tubes instead of one? Think of it as spreading the workload. Twin-tube designs give you a much larger surface area to emit heat. This keeps the glass from getting blasted in one tiny spot and overheating. We use high-purity quartz because it can take the thermal shock without cracking. But the real secret is in the end-caps and connectors. If those aren’t seated perfectly tight, the heat will eat through your terminals long before the filament even thinks about quitting. A few things to keep in mind The great thing about these is that you stop seeing those annoying “stripes” on your glass. Everything comes out smooth. But, there’s a trade-off. Long tubes are fragile. One clumsy bump during installation and—snap—there goes your quartz. I always suggest using reinforced mounting brackets to soak up any vibrations from the factory floor. Also, these things put out a massive amount of heat in a small space. Don’t skimp on your cooling fans. If you don’t move that air, you’ll end up warping the actual kiln housing, and that’s a headache nobody wants.