Not wanting to risk the aftermath of using the kitchen oven, I picked up locally a mid-sized, used Blue-M lab oven a couple years ago. Not pretty, but it works. Interior shelves are 11" x 16" and the useable height is about 16". The temperature controller isn't calibrated, but set with a simple liquid-filled thermometer (the oven has a thermometer mounting clamp and hole in the top), it holds a stable temperature, up to 200 deg C (392 deg F). Good enough for casting work, but I mostly use it at 80 deg C to bake small to mid-size painted parts. Model SW-17TA. Very simple construction, and with some luck, can be found for $25-$50 from industrial surplus sellers. Mine needed the power cord replaced.
