Hairline frame cracks or cracks in the butt cap at the end of a tennis racket's handle are rare, but can develop over time from wear and tear. Unfortunately, a permanent repair to restore the structural integrity of the racket’s frame is not possible. Even so, a temporary patch or butt cap replacement may buy you enough time to purchase a new racket.
Frame Crack Patch
The surface around the crack must be clean before you make any repairs. Take a cotton swab, apply a dab of isopropyl alcohol to the swab, clean the area and wipe the frame dry with a clean rag. Allow the area to thoroughly dry. Run a bead of fast-bonding cyanoacrylate glue, such as Super Glue, along the crack. Wait until the glue has dried and apply a second bead of glue. Let the area thoroughly dry before using your racket.
Butt Cap Repair
Unlike a frame crack patch, the repair of a cracked butt cap restores the racket's handle to a new condition. A replacement cap, which can be acquired through many racket dealers, is required. To install the new butt cap you must unwind and remove the grip, and then remove the existing cap, which is held to the handle by small staples. Once you've done this, simply slide on the new cap, staple it to the handle and rewrap the grip.