I am fairly new to powder coating. What I have learned is that even with a quality oven, it can be challenging to maintain a constant temperature for curing powder coat. At first I would preheat my convection oven to 400 degrees and wait for it to stabilize at that temperature, as monitored by two different thermometers. I would then place my tray with the bullets in the oven. The temperature would drop considerably as the oven tried to maintain the 400 degree setting and bring the contents back up to the setting. In that effort to rapidly reheat the oven, the temp would swing far above 400 degrees and then take a few minutes to settle down to that setting. I came up with a new technique that works well for me and may help others who have the same issue. I don't preheat the oven. I place the tray in the oven first, then turn it on and set for 400. I have found that using this method the temperature doesn't go above the 400 degree setting because it evenly heats the oven and contents together so when it reaches 400 degrees it stabilizes at that point. By then the powdercoat has melted and I can begin the 20 minute cure time. It works very well for me using this method.