Classical guitar repair help

[dozymuppet]

A few months ago my daughter's guitar took a bit of a tumble when someone forgot to zip the case up on the way to school. We looked into getting it repaired, but the quotes that came back were as much as the guitar itself ($300+). At the time I was about to just go and buy a new one, but got out the duct tape out and did emergency repairs instead. Surprisingly, it has held its tone well, and it generally stays in tune.



It's tricky to see in the photo, but the top has come away from the side for about 15cm, and there is about a 6cm split on the top.

School holidays are coming up, and I'm tempted to have a shot at doing the repairs myself while it's not required for a bit. I'm not looking to make it showroom perfect, but would like to have a crack at making it somewhat whole again.

I guess my first questions are:

• What sort of glue do I need?
• How long will it need to cure?

[Simon Barden]

Traditional classical guitars would use hide glue. But a $300 one is more likely to use Titebond or PVA in its construction.

Your best bet is to prise the top off as much as you can, and use sanding sticks or sandpaper taped to thin bits of wood to sand as much of the existing glue off as you can, or use a small sharp edge to scrape it away.

Ideally you'd remove the top completely (which also requires removing the fretboard), sticking a patch over the split on the underside, and then gluing the top and the fingerboard back on (which is why the repair would cost so much).

You may be able to glue a thin wooden patch over the split on the inside if someone with thin arms can hold it inside, but clamping it in place cold be an issue unless you've got a specialist clamp. Otherwise a wood patch and some CA gel would allow some strengthening for the split and would set without needing clamping.

Then use a brush to apply Titebond to both sides of the gap, and clamp the top back on, wiping off any excess glue with a damp cloth.

Traditional classicals would be French polished, but that looks more like a Poly finish. If the finish needs repairing, then you'll need to sand the area around the split and join to key it, but could then use wipe-on or spray poly to finish the job.

[dozymuppet]

Ok great, that all makes sense, particularly cleaning up the area and applying titebond. I'm not so keen on removing the whole top for this project (something for practicing on an op-shop find or the busted uke I've got laying around...). I'll have a think about how I can get in under the split on the top though. That sounds worth doing if I can I figure out a way.

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[Simon Barden]

Thin knife and some thin wooden wedges. It's one of those cases where it's better to increase the amount of 'damage' so that it can be better repaired. It may also be worthwhile watering down some Titebond to say 70:30 Titebond:water so that is penetrates the remaining crack areas at the ends that you can't get a small artist paint brush and full-strength Titebond in. It all helps. And if it really is a very small crack and you don't feel happy about opening it up, then you could mask off around it and wick in some thin CA and then clamp it down.

[McCreed]

Simon has offered good advice and I'm certain has way more acoustic repair experience than me.

I'd be interested in seeing what's under the "100 mile an hour tape" (that's what we called it back the car racing days) just to put the damage and repair next to each other in my head.

[Simon Barden]

Not a huge amount of acoustic guitar repair experience, but a friend makes classical guitars (and is now branching out into steel-strung as there is a limited market for £3k+ classical guitars), and posts lots of pictures and explanations on Facebook, so I've got a good idea of what goes on inside them.

[dozymuppet]

I'd be interested in seeing what's under the "100 mile an hour tape" (that's what we called it back the car racing days) just to put the damage and repair next to each other in my head.

School holidays coming up. I'll do the big reveal then XD


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[McCreed]

Not a huge amount of acoustic guitar repair experience, but a friend makes classical guitars (and is now branching out into steel-strung as there is a limited market for £3k+ classical guitars), and posts lots of pictures and explanations on Facebook, so I've got a good idea of what goes on inside them.

That's a good friend to have and I understand those market limitations. I 've owned cars that didn't cost £3k!
I have great admiration for anyone that undertakes building any acoustic instruments. Give me solid slabs o'timber anyday!

[phrozin]

Simon has offered good advice

When it comes to guitars Simon is the most clued-up guy on the forum by a long way, he's better than google

[dozymuppet]

Revealing photos as promised:






This also shows a smaller split about 2 cm on the top, and also that the top has popped out over the top of the binding at one section. So I'm assuming I'm going to have to apply a bit of brute force somewhere to get it back inside the side. Just not sure how much "give" it has.

(Also, for the Perth crew, I went to Timbecon in Canning Vale yesterday, to buy some Titebond. That place is bloody dangerous...)