I had the same problem some other reviewers did with the foam turning back into a brown liquid after application. Here's what customer service said:
"...all one-component polyurethane foams, like MaxFill, require both air and moisture to cure properly. This is why one-component foams, like MaxFill, don't work very well in enclosed spaces. When you inject foam into a void, only the foam closest to the injection points will have enough air and moisture to cure properly. The rest of the foam, as you unfortunately discovered, will breakdown into a liquid and make a mess.
In order to make it set-up within an enclosed space, you must either: 1) make the space no longer enclosed by opening it up so all of the foam would have access to air and moisture OR 2) apply the foam in layers, though in an enclosed space, this is also very difficult.
We don't normally recommend injecting foam into enclosed spaces, though if you must, we recommend using a TWO-component foam. Unlike one-component foams, like MaxFill, two-component foams will harden due to the chemical reaction taking place and requires neither air nor moisture. However, the common problem with 2-component foam is that it tends to have a much higher expansion rate. This means you must be very careful when injecting the foam into an enclosed space, so as not to over fill. During the expansion process, the foam does not necessarily follow the path of least resistance and will expand in all directions at the same time. This means that if too much foam is accidentally injected, and it continues to expand, it could end up doing damage. In walls, this could lead to broken drywall; with your cooler, it could split open the top."