What is the recommended temperature to turn off the Vent-Sure kiln vent when firing glazes, specifically to reach a target temperature of 2190°F? Do glazes continue to release gases after reaching around 2000 degrees? Is there a general temperature at which the vent should be turned off?
Answer:
For optimal performance, it is advisable to keep the Vent-Sure kiln vent running throughout the entire heating process. This ensures that any corrosive fumes are extracted before they reach the kiln's elements, wiring, and other metal components. However, if you need to expedite the cooling process, you can leave the vent on.
During high-fire glaze firings, the outgassing of gases typically occurs until the kiln begins to cool down. Once the glaze has solidified and the clay has vitrified, no further gas emissions take place.
It's worth noting that the heat inside a red-hot kiln consists mostly of radiant heat, and as the temperature rises, the number of air molecules present inside decreases. Consequently, turning off the vent slightly before the firing is complete provides only a marginal improvement to the heating rate. In most cases, it is preferable to leave the vent off during the cooling phase for a slower cool-down.
