Thanks, I love your name man, lol. That Expanded Polystyrene Foam sure cuts easily with a soldering wand, lol. I am glad I made my keg-tun lids out of it. The rigidity when covered with a plastic or latex coating is great and insulates very well. I tried both types of insulation on my lid project and the EPS lid is as tight as a drum, while the Reflectix insulated lid looks like a raisin, lol.
I really am having problems finding the correct temperature readings in a 15.5 gallon keg. I checked overnight. As insulated as I am with my new setup I didn't lose but a few degrees. However, moving the thermometer around showed significant temperature fluctuations from what I thought the temperature was. I have to find a way to get a more complete reading of my mash temperature now that I am not losing those degrees through the walls of steel like I used to. The problem with those coolers is the lid isn't insulated near enough. I mean they are made for keeping cold, not really for keeping hot. I bet the same cooler with a better insulated lid would be cheap and good. I mean, I am talking some EPS, particle board, and latex paint and you would probably not drop 2 degrees an hour.