Posted 11 October 2018 - 02:22 AM
You need a Sash Clamp (you can find them on Amazon), some PVA glue, masking tape and some suitable packing pieces to protect the guitar (MDF is a good material for this).
1. Mask the edges of the split (because I don't know what effect the glue will have on the nitro finish)
2. Rub the PVA glue into the crack with your finger, making sure you get the glue as deep in the split as you can.
3. Place the packing pieces on either side of the guitars body and use the Sash Clamp to pull the split together, pull it as tight as you can without damaging the guitar. This is where having three hands would help!
4. Remove the masking tape (to make sure it doesn't stick to the guitar when the glue sets) and check to make sure there's no glue on the lacquer, if there is remove it with a damp cloth.
5. Leave the clamp in place as long as you can, ideally 24 hours but you need to keep an eye on your packing material to be sure it won't make the lacquer.
Good luck, I hope this helps.
Ian