K42

Does anyone have suggestions for making a temperature controlled wet box? My pottery space is on my porch, but I can store most of my clay in the basement. I'd like to store a bag of clay and in-progress pieces on the porch, but it keeps freezing. I thought about storing stuff in a cooler or unplugged mini fridge and trying to add heat by adding hot water and replacing it every few days. Maybe a birdbath heater in a small bucket of water would do the trick? I've seen instructions for making a heated fridge for brewing purposes (instructions here:https://www.youtube.com/watch?v=LUj89cBBgDc, but that seems overkill. I just want it to stay above freezing. Has anyone found any tricks?