New answers tagged lutherie
Have you considered putting it in a case instead? That way it is protected from dust, dirt and damage - nobody will be tempted to grab it and it will also look nice "framed" this way. You can also test the smudge risk by putting a small dot on the back with the same pen, leaving it a few hours and then seeing if it does actually smudge when you rub it.
If you are just hanging it on a wall and not playing, then don't worry about any of the acoustic properties and give it a couple of coats of spray lacquer or acrylic. Just spray the body - necks don't do well with lacquer - very difficult to avoid it cracking or rubbing off. So if it is just the body that had been signed then mask off all hardware and the ...
I would check with a local luthier, he surely knows the right materials for both the guitar body and the signs so that none of them will be damaged.
I imagine you could use a clear acrylic coating on the body of the guitar if you aren't planning on playing it. Even then, it shouldn't affect the sound too much.
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