Why your glass oven temperature readings are lying to you
Ever wonder why your pyrometer is giving you weird numbers? It’s a common headache. Here’s the thing: most sensors assume they’re looking at a “blackbody,” but molten glass isn’t that simple. When you toss in specific chemicals or additives, they create these invisible “absorption bands.” Basically, your additives are blocking certain wavelengths of light. If your sensor is trying to read through one of those blocked spots, you’re getting a fake reading. It’s frustrating. You think you’re at temperature, but you’re actually not. The fix is simpler than it sounds. Instead of using a generic sensor, we customize the infrared spectrum to match your specific glass recipe. Most off-the-shelf sensors use broad filters. They try to see everything at once. But if your glass has a high concentration of certain oxides, those chemicals “steal” the infrared energy. The sensor gets confused. We just shift the sensor’s focus to a “transparent” window—a spot where your additives aren’t interfering. This way, the sensor sees the actual heat of the melt, not just the chemical signature of your ingredients. How we actually do it We use narrow-band interference filters. Think of it like tuning a radio to one specific station instead of listening to the static of ten different channels. By narrowing that window, we kill the noise. You get a clean, honest signal. Of course, we can’t guess. We need to know your exact glass recipe so we can spec out a filter that hits the sweet spot of maximum transmittance. The trade-off Now, there is a catch. When you tune a sensor for a specific borosilicate mix, it’s not going to work on a soda-lime batch. You’re giving up versatility to get pinpoint precision. Also, these narrow filters are a bit picky about angles. If the sensor isn’t lined up perfectly with the oven opening, the signal drops. It’s sensitive. That’s why we suggest a rigid, fixed mount. Once it’s locked in, it stays locked in, and you don’t have to worry about drift.