Hi all- I recently changed to using a plastic waterer for my birds. I found that the metal ones would corrode rather quickly (I use cider vinegar) and lose their shape making it difficult to keep them from leaking. The issue is winter has arrived and I have historically used a regular plug-in base heater. I am wondering if it is safe to put plastic on this base or not? Should I put an insulator between like a piece of plywood or ceramic? I wonder if it would even keep the water from freezing though without direct contact... Any thoughts appreciated!