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This repair is relatively simple on the surface. The hard part is designing the clamping rig. There are generally two styles employed. The first utilizes a strap attached at the top of the headstock and the end pin. The strap is tightened so as to create clamping force. The second method uses F or C style clamps with appropriate clamping cauls. The cauls look like wedges. They are created (custom) at a complimentary angle to the headstock to allow the clamps to operate in a straight line.
- Remove strings and tuning machines.
- Open the crack using either clamping method.
- Remove any dirt or foreign objects from the crack.
- Avoid damaging wood fibers. Realign any that might impede having perfectly mate surfaces.
- Apply glue.
- Reverse clamps.
- Clean up any glue squeeze out.
- Allow to glue to set for recommended time.
- Final cleanup.
- Touch up if desired.
- Reinstall tuners and restring.
- Set up.
- Play.
Wood glue is the glue of choice, either yellow or white. White (polyvinyl resin, Elmer's) has a longer open time of seven minutes. Yellow (aliphatic resin, Titebond) is a bit stronger with an open time of five minutes. If your experience with glue is limited to construction adhesives or making Popsicle stick cabins, go with white as it will allow for a little more time to clean up a mess. If you elect to use a brush, make sure to clean any loose bristles from the brush before using, and make sure that there are none in the joint before clamping. These glues can be cleaned up with a damp rag.
Some folks will recommend the use of epoxy because it is stronger than wood glues. While this may be true, it is to be noted that wood glues are stronger than the wood they hold together. Epoxy clean up typically uses acetone. Acetone will disolve some finishes very quickly. It is not a good idea to get it on your skin and it will eat through most protective gloves. If you are an experienced tool user the choice is yours.
Standard caveats:
Practice the clamping routine at least once or twice before applying glue. Seven minutes seems like a long time. It isn't.
Assess your skill level before attempting this repair. If it is done incorrectly it will be difficult (using wood glue) to nearly impossible (epoxy) to reverse and re-do. Expensive, too.
As always, if you think a tool is a piece of software or someone who insulted your significant other, have to rummage through kitchen drawers or the garage to collect together the other kind of tools, or think changing a tire is automobile mechanics please take the instrument to a professional for repair.
and take photos of the neck
