Okay, just started building my insulated waterer. I took a 3L bucket and a 8L bucket, glued some space blanket to the bottom of the smaller one, and then taped some more space blanket around it. Then I glued it to the inside of the larger bucket. Once the glue has dried, I'm going to pack some rock wool inside plastic to make it water tight and put that around the empty space in there, and then cut out a round piece of polyurethane insulation to go on the top. I might make a hole in that though and make a funnel out of a soda bottle that sits there for easy filling. Not sure about that yet, because then I can't look into the thing that easily. But I hope this turns out well.