Things You'll Need
Instructions
Assemble the frame of the sandbox. For two of the ends you'll use 2 x 12 inch wood that is cut to 4 feet. For the other two, use the same 2 x 12 inch wood cut at a length of 3 feet, 10 1/2 inches. Use untreated wood as pressure treated can contain harmful chemicals. Use 2 1/2 or 3-inch galvanized nails to assemble the frame. Ensure that the ends of the shorter pieces are on the inside of the longer pieces.
Attache an 11 1/4 inch piece of 4 x 4 wood to each corner. This will help to secure the frame. For extra security and strength, use three nails on each side the the 4 x 4 wood.
Cut 3/4 inch plywood into 90 degree triangles that have 15-inch sides. Attach these to each of the four corners to create seats. Ensure that the triangles are flush to the edge of the box.
Fill the sandbox with sand. Use sterile playground or sandbox sand, which can be found at home improvement stores.