In the small tabletop ovens that most people use for baking polymer clay, the temperature control is not a proper heat controller. The temperature control is approximated by a spring switch behind the dial. As the spring heats up, it turns off the element. Then, when it cools down, it turns the element back on again. When you turn the temperature dial, you’re just tightening that spring. There is no true thermostat or sensor.
If you put the oven in the garage, on an unheated porch, or in line with the AC vent, your oven “thinks” it’s still cold. So the oven’s element stays on, blaring hot, and is toasting your pieces like little grilled cheese sandwiches.
This isn’t just a matter of fumes and safety. The direct heat will not cure your pieces properly, either. You’re likely to get color change, bubbles, and incomplete curing. Yes, it’s possible to burn AND underbake your polymer pieces!
There are a few solutions. The easiest is to move the oven inside or at least to an unused room.
You can also do some things to help your oven keep its temperature. Place ceramic tiles in the bottom of your oven under the element. Place tiles on top of the oven. Place a tile or two on the rack. These will help hold the heat. Try blocking the oven from any drafts. Maybe you can make a “room divider” or small area so the oven heats up a little “room” around it.
However, please don’t block the oven’s vents or put anything flammable near the oven’s sides. You don’t want to overheat the oven. You don’t want the element to stay on constantly, or the oven can malfunction. Watch it!
Ovens are designed to be used at average home temperatures, and putting them in a cold environment dramatically changes how they function.
