How To Build An Insulated Cooler Bench

Tom and Kevin O’Connor cut the pieces to size and assembled them in about 6 hours, using about $250 worth of materials, beyond the cost of the liner. They could have used less expensive wood and metal, but Tom was in no mood to compromise. “I wanted to build something that would hold up against the weather and look good for a long time,” he says. Mission accomplished.

Build It | Modern Platform Bench

The insulation is foil-face isocyanate rigid foam that is hidden between cedar and a copper bin. Tommy chose to use cedar as a frame for the bench because it is weather resistant and good for outside. Although he built his prototype with mahogany, cedar is a much lighter wood and will be easier to move around.

Steps for Building an Insulated Cooler Bench

Step 1: Cut and plane

Rip the 4x4 legs on a table saw so each face is 3 1/8 inches wide. Using the cut list below, trim them to length on a miter saw, then plane each face to a 3-inch width. (Don’t have a planer? Rip the sides to their final width on a table saw; sand out any blade marks.) Rip the 1x cedar boards and MDO panels to width; cut them to length.

Step 2: Mortise the sides

Using a loose-tenon joiner, make a series of matching 20mm-deep mortises in the edges of the cedar sides and the faces of the caps on each side’s top edge.

Step 3: Glue the pieces together

Brush wood glue into the mortises and onto the mating edge and face of the cedar cap. Tap the 5mm tenons into the edge of one side, then tap the cap’s mortises into the tenons. Clamp both pieces together. Repeat with the other three sides.

Step 4: Attach the MDO

Glue the pieces to the inside faces of the cedar sides; staple them to the cedar. To support the basin’s edge, fasten 1x cedar to the underside of the cap. Clip the ends for a tight fit.

Step 5: Mortise the legs

Plunge-cut 8x22mm mortises into two adjacent faces on each leg and the ends of the cooler’s sidewalls. Drill pocket holes through the faces of the MDO: four in the ends of each short side, eight in the ends of each long side. Smooth the wood parts with 120- and then 180-grit sandpaper.

Step 6: Attach the sides

Glue tenons into the leg mortises on the cooler’s narrow end; apply glue next to them. Drive pocket screws into the legs with a 6-inch square-drive bit. Fit the glue-covered mortises over the tenons in the long sides, and drive in four more pocket screws. Do the same on the other short side.

Metal liner choices

The custom copper basin that Tom used in this project came from an architectural sheet- metal shop that makes liners for shower pans. This one could easily outlast the rest of the chest. But that kind of longevity comes with a steep price: around $500. For about half that, you could fit a couple of off-the-shelf, stainless-steel undermount sinks into the chest, after cutting drain holes in its bottom panel.

Step 7: Add insulation

Turn the cooler upside down. Cut four 8¼-inch-wide strips of foil-faced foam and fit them against the sides of the chest. Notch a 21½-by-42¾-inch sheet of foam to fit on top of the sides’ foam pieces.

Step 8: Cut a drain hole

Cut two panels of MDO to fit the cooler’s underside. Leave a 10-inch gap between the panels, then screw them to the MDO on the sidewalls. Using a hole saw, drill a 3-inch hole in the center of the foam for the basin’s drain.

Step 9: Drop in the basin

Set the chest upright and slide the basin between the foam panels. Fit the basin into the drain hole, then rest it on the cooler’s inner lip.

Step 10: Prep the lid

Using mortises and tenons, edge-glue the 1x cedar boards into two panels; sand them smooth. Cut rabbets, 1/2 inch by 3/4 inch, into the frame pieces’ inside edges, and the ends of the crosspiece. Cut the frame’s half-lap miters (see “Better Miters for Outdoors,” below).

Step 11: Assemble the lid frame

Mortise the crosspiece ends and the midpoint of each long frame piece. Glue tenons into the ends, and into the frame’s mortises. Glue and clamp the half-lap miters and fasten each one with a 1¼-inch stainless screw. Trim the cedar panels to fit inside the lid’s frame. Apply sealant to the rabbets; bed the panels in it. Turn the lid over; fasten the panels with 1¼-inch stainless screws. Apply sealant around the edges of both recesses in the lid; bed the foam pieces in the sealant, foil facing up.

Step 12: Attach the lid

Trim the copper sheet to fit the frame’s perimeter and secure its edges with 3/4-inch stainless screws. Fit silicone weatherstripping alongside it. Screw a piano hinge to the underside of the lid; attach the hinge’s other leaf to a 2 1/2-inch-wide cedar strip. Place the chest upside down on top of the lid, line it up with the hinge, and fasten the strip to the back of the chest with 1 1/2-inch screws. Finally, mount a soft-close strut on the lid to reduce strain on the hinge and prevent the lid from slamming shut.

Tip: Better miters for outdoors

Unlike a standard miter, where both pieces sit side by side, the half-lap miters Tom uses in this project sit one on top of another, eliminating any chance of the joint opening up. To create the four half-lap miters that frame the bench lid, Tom set the depth stop on a miter saw and made repeated side-by-side crosscuts to remove half the stock’s thickness. Then he mitered the ends, as shown.

Resources

Tom built the cooler bench out of dimensional cedar, which can be found at any lumberyard. To cut all the boards to the proper dimensions and assemble the bench, Tom used a variety of tools, including a Domino Joiner and a Kapex KS120 sliding compound miter saw, which are manufactured by Festool, and an Industrial Table Saw from SawStop. Tom and Kevin secured everything together with pocket screws and a K5 Pocket Hole Jig from Kreg and some wood glue from Gorilla Glue. The copper bin and copper piece for the top of the cooler were both custom made by The Tin Shop in Beverly, MA. All of the other tools and materials Tom and Kevin used to build the bench can be found at home centers.

Materials

4x4 clear cedar, 8 linear feet 1x10 clear cedar, 18 linear feet 1x3 clear cedar, 6 linear feet 2x4 clear cedar, 12 linear feet 120-, 180-grit sandpaper 1/2-inch medium-density overlay (MDO), 7 square feet Loose wood tenons, 10x30mm and 5x20mm Copper basin Copper top piece ¾-inch foil-faced foam, 13 square feet Wood glue ¾- and 1¼-inch stainless-steel screws Weather stripping Silicone sealant 36-inch stainless-steel piano hinge Screen door compressors 20-ounce copper sheet, 21½ by 39½ inches