Im looking to build a super insulated cooler....or ice chest. Im hoping once its cooled off, it will keep ice for several days. I have a 100qt cooler, and am planning on building a wooden box, 6" bigger than the cooler in every direction.....and backfilling that. Im not sure if 6" of insulation is enough or overkill. Im not sure if spray foam insulation would better than say, blown in.... Open to ideas and material ideas.... Best, Sca
Polyurethane foam is what you'll want to use based on what the best coolers use. You can buy a 2 part liquid and use that. They use it for boat floatation too. How much will you need? You're need to determine that, depending on how thick of insulation you'll use. I'm guessing you'll do 2-3" around the entire cooler walls. It's not cheap though. $40 for 1.25 cubic feet worth in a smaller amount, but you can buy a gallon or bigger size too. That's one reason why those rotomolded coolers are expensive, regardless of what name is on the outside. The rotomolding exterior isn't expensive, it's one of the least expensive ways to make things like this, but the foam has been expensive for decades at least.
