With fabric designs becoming more complex, many designers now glue denim directly to denim to create some intricate designs. The key to doing this process at home is using the right glue. While traditional white glue is great for gluing paper to paper, it is not waterproof and will wash away when clothes are laundered. Thankfully, there is fabric glue that can be used to glue denim to denim.
Practice placing the various pieces of denim so that you know the exact position of each.
Turn the pieces over and place a bead of fabric glue around the edges about 1/8 an inch from the edge to avoid the glue seeping out.
Press the denim patch onto the denim, gently pushing on the edges.
Leave the glue to dry for at least 24 hours before washing.
For an extra strong hold, consider using a button hole stitch around the outside of the denim patches.