I have a 1993 Hunter 37.5, which has a good sized ice box already set up with an A/B refrigeration system (large evaporator box.) The refer box itself is a large rectangular box, approx 30 x 17, and the lid is divided into two doors (one smaller, one larger.) I want to construct a divider to split the box into separate freezer and frig sections, with a spillover fan cooling the frige from the freezer side. From the setup of the doors, it should work well, and there is a 3/4" x 1" bar accross the top that will be the top of the divider and effectively separate the two sections. Others here have that setup already, but no one seems to know how to build the divider itself. My question is how should I build a dividing wall for the box? What should it be made of? Some I've seen appear to be 1-2" wide walls covered in formica. What's the material that's sandwiched in between? I'm fairly handy, and have relatives that are even handier, so we can make about anything. A/B suggested something called "Z board" encased in formica, but I've not been able to find either a source or any information on it. So, I'm at square 1 in the process. Do you have suggestions/sources/advice? Any help will be appreciated.