My parents bought this kiln to make vitreous enamel, but they just cant get it to work properly. The way we make vitreous enamel works (like jewelry, not just that, but this was the the best place I could find to ask) is to heat up the kiln to 860 celsius, open the door, put in the work, close, wait one minute, take it out. With my kiln at home this works perfectly, the temperature only drops around 10-20 degrees if I’m fast. Every time they tried it with this kiln, the moment they opened the heated up kilns door, the temperature droped several hundred degrees. Is there a way to avoid this? Where they are this is the only brand of kiln they could find, so they are quite frustrated.