To make the breakaway box hinges stronger, you need to apply them on the inside and the outside of the hinged sides. When the inside hinges have been applied, (see previous step) turn the box upside down so the base is facing you, and apply hinges to the base of the box and the outside base of the sides, just like you applied them in the previous step. Cover the fabric strip with glue, right to the edges, then fix it to the base of the breakaway box. Line up the side you are preparing to hinge, and press the cloth hinge firmly over the base of the side, making sure the cloth adheres smoothly without bumps or folds, to the base of the hinged side. It is important that the hinges are applied smoothly so they won't show through any finishing paper. Test that your hinges work and that there are no gaps which allow the side to swing away from the base of the box when it is in the upright position. Trim away any areas of fabric overlap where the hinged sides meet to keep the thickness of the hinge material to a single layer across the base of the box.
Set the box aside to dry, with all four hinges now in place. The inner hinge you applied in the previous step should help to hold it securely while the hinge on the outside dries.