For some reason, Hunter, in its infinite wisdom in the early 80s decided that a plywood lid, with another piece of plywood screwed to the underside would be decent insulation for an ice box....NOT. So the first part of this project was getting rid of the insulation plywood.

See 2 Foam from Home Depot

A quick trip to Home Depot got me a sheet of 2 Insulation Foam - R Value of about 8 - which I cut to the dimensions of the opening of the box.

See Gorilla Glue setting

Using my handy squeeze bottle of Gorilla Glue