Shoes don't last forever and need to be repaired from time to time. The most common repair is fixing a split shoe sole. The sole is made up of two pieces--the outsole and the welt. According to the "Shoe Guides Anatomy of the Shoe," "The outsole is the exposed part of the sole that is in contact with the ground. The welt is a strip of material that joins the upper part of the shoe to the sole." A split shoe sole takes place when the welt separates from the outsole. The welt and outsole can usually be repaired by gluing them together with a shoe repair adhesive.
Cut all broken or loose threads with a utility knife and remove them from the area to be glued. Clean this area with a damp paper towel until all loose materials, which could limit the adhesive's bond, are removed. Center the outsole with the welt to realign the sole of the shoe. Inspect the edge of the two pieces for uniformity. If the edges of the welt and outsole are not realigning, the shoe repair clamps can keep these materials together to reform the alignment.
Apply a generous amount of shoe repair adhesive to both the welt and the outsole using an adhesive applicator brush. Stick the welt and the outsole together and place shoe repair clamps around the entire sole of the shoe. The seam of the outsole should be firmly pressed together along the entire length of the split. The clamping process may squish some of the adhesive out of this seam, but it's OK.
Slide a shoe tree inside the shoe to maintain the shape of the shoe. Set the shoe upright so its sole is in contact with a hard surface such as a floor. Cover the shoe with a bath towel for padding and put a few heavy books on top of the towel to ensure the outsole and welt are pressed together in the centre of the shoe's sole. Follow the drying time calculations on the label of the shoe repair adhesive before removing the clamps and wearing the shoe. Use a fine grit sandpaper to remove any adhesive around the perimeter of the shoe sole. Touch up the sole colour with like-coloured shoe polish.