Tempeh or yogurt oven legs

I printed these after finding 3 stackable wire racks the perfect size for a tempeh oven. #8 machine bolts are used at the corners to attach the upper and lower racks to the legs. To make tempeh, I put a small heating pad on the lower rack and slide in the middle rack with the bags of beans on it. The whole rig fits inside a very large insulated tote which gets zipped shut when incubating. The heating pad is controlled by an temperature-sensor relay ($15 on Amazon) which turns the heating pad on