Getting tempering right when you’re working with screen-printed glass is a bit of a balancing act. It all comes down to how you handle the heat. If you crank it up too fast, you’re going to burn your ink or watch your patterns warp right before your eyes. But if you’re too timid with the heat, the glass never hits that sweet spot—the transition temperature—and you end up with a product that isn’t strong enough. That’s why we lean on short-wave infrared lamps. Keeping the patterns crisp The beauty of short-wave IR is that it punches through the glass surface quickly. It heats the bulk of the material without just baking the ink on top for too long. But you can’t just plug them in and hope for the best. You have to get your lamp wattage and spacing exactly right so the heat is even across the whole sheet. If you’ve got hot spots, your ink will bleed or peel, and you’ve just wasted a piece of glass. I usually suggest a zoned heating approach. By tweaking the power in different sections of the tunnel, you get a steady ramp-up. It stops that “thermal shock” that usually kills high-detail prints. The hardware headache Now, high-wattage quartz lamps are great for fast cycle times. They give you the density you need. But there’s a catch. These things runhot. If your cooling blowers aren’t up to the task, you’re looking at melted wiring or warped mounts. And don’t forget the reflectors. If they get dirty or oxidized, your efficiency tanks. You’ll find yourself pushing the lamps harder just to hit your temps, which just burns out the tubes faster. Finding the sweet spot At the end of the day, it’s all about the cooling rate. You heat the glass to the tempering point, then you quench it. The goal is to get enough energy into the core of the glass so it’s structurally sound, while keeping the surface cool enough that the ink doesn’t degrade. It’s a narrow window. Really narrow. Get the timing off by a few seconds, and you’re left with either fragile glass or a blurry mess of graphics.