How to insulate a cooler box
I have just bought a plastic cooler box. It is two boxes in one: an inside lining, an air cavity, the outside case and of course a lid and handle.. I would like to improve the insulation. I have a 750ml can of expanding polyurethane foam which I thought of spraying into the cavity. It will dry in an hour. I can work out the exact volume to be filled with the foam by prefilling it with water and measuring the amount of water that pours out of the cavity , but I do not know the best way to apply the foam. Any ideas, please. For example should I wrap the inner box in anything before pushing it into the wet foam that I spray against the inside of the outer case?