DIY Icebox

Cut the base section of the box out of ¼-inch plywood, using a table saw. This will define the maximum width and length dimensions of the box. Use these dimensions to cut two end and side pieces that will form the outside layer of the box. Cut the side sections a ½-inch shorter than the length of base to facilitate glue to the end sections.

Spread glue around the rim of the base, on the inside edges of the end pieces and the ends of each side piece. Press the pieces into a perfectly vertical position for five minutes to allow the glue to set. Squeeze a bead of caulk along the inside base of the walls to seal the outer layer of the box.

Cut the 2-inch foam insulation to the inside diameters of the box using the table saw, with the base spanning the entire inside dimensions and either the end or side pieces 4 inches short to facilitate a tight “T” seam. Spread glue on the back side of each foam piece and slide them into position against the outer layer of plywood, once the glue on the plywood pieces has cured -- around two hours depending on temperature.

Cut the inside layer of plywood using the table saw. Glue the sections into place against the foam.

Paint the resin mixture over the inside and outside plywood surfaces to seal the plywood from water. Caulk the inside base of the inner plywood layer.

Cut a rectangle piece of plywood to the outside dimensions of the box. Place over top of another piece of plywood, using it as a template to cut out an identical rectangle. These sections will serve as the seal between the top of the box and the lid. Clamp both pieces together and cut the center of the boards out, leaving a rectangle strip 2 ½ inches wide. Glue one section to the top of the box and paint with resin to seal the base section of the box.

Cut a piece of 2-inch foam ½ inch short in both width and length, to begin the lid building process. Cut 2-inch strips of plywood for the both the length and width of the foam and glue to the side of the foam pieces. Cut the top and bottom panels for the lid to the outer dimensions of the box and glue them to the top and bottom of the foam respectively.

Glue the rubber gasket to the top of the box base, in the center of the rim. Round the top edge of the lid with a router, ensuring not to cut through the plywood. Paint the entire lid with resin. Screw in a lid hinge onto the back side of the lid, equally spaced to share the load of the lid. Screw a “latch and throw” style latch to the center of the box joint on the front side of the lid.