Whats the best method for soundboard crack repair?

Even if it ain't broke you can still fix it.
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bishopbautista
Posts: 5
Joined: Thu Mar 01, 2018 2:07 pm

Whats the best method for soundboard crack repair?

Post by bishopbautista »

Hello everyone,

I recently bought a used Flamenco guitar and by the time I received it, I notice it had a lot of problems. At this point I can't return it and it's not worth paying someone too fix it so I was going to give it a shot myself. I've got a series of grain cracks on the soundboard and the bridges starting to slightly lift at the back. I'd appreciate anyone's advice on how to best go about repairing this. If there's a video that covers this type of repair Perhaps you can forward it to me? :) Again any advice is greatly appreciated

Please see images attached

Image 01: https://pasteboard.co/H9UZsNj.jpg

Wishing you all the best!

-Bishop
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Diane Kauffmds
Posts: 3246
Joined: Sun Mar 09, 2014 8:13 pm

Re: Whats the best method for soundboard crack repair?

Post by Diane Kauffmds »

The bridge needs to be taken off, cleaned of all glue residue. The top will have to be prepped by removing all glue remnants too. Then, you can glue and clamp the bridge. It will probably come off easily with a hammer and chisel. You can also use heat. There is a video from John Hall, here on the forum, that demonstrates bridge removal with a chisel.

The soundboard separation is due to dryness. I've repaired a few of these. You need to rehydrate the guitar, which will help close that separation/crack.

There are a lot of ways of doing this. You can use something like an Oasis, with the guitar in the case. Or, put the guitar into a large plastic bag. Along with the guitar, place a couple of cheap plastic containers with lids, each containing a wet sponge. The sponges should be wet, but not dripping. Drill a few small holes in the tops. Close it all up in a bag, and check daily. I've also put one of these containers inside of the soundhole, laying it on a cloth inside of the guitar, then I close the case.

If you have a controlled humidified room, just put the guitar there, with the case open. It may take a few days, but the crack should close.

Once closed, use 2 cleats, and glue them over the closed crack. Depending on the length of a crack, you may only need one. Always put a cleat over the end of a crack, to keep it from spreading. If it's long, I put a second one in the middle. They can be made thin, so they don't interfere with the vibration. Use Original Titebond, cold hide glue, hot hide glue, fish glue. Do not use ca glue on spruce, because it can discolors it. CA glue can be used on the sides/back.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
bishopbautista
Posts: 5
Joined: Thu Mar 01, 2018 2:07 pm

Re: Whats the best method for soundboard crack repair?

Post by bishopbautista »

All I can say is wow what an incredible reply! articulate comprehensive and complete I can't thank you enough for taking the time to explain all of this to me in such great detail. A lot of it reinforces what I've seen on YouTube and I've already read about but I feel an actual level of confidence hearing it from you. A couple quick questions.

1. So for sure the bridge has to come off I can't either leave it until it pops off or just try to re-glue it the way it is?

2. I'm taking your advice and humidifying the guitarI don't have a proper guitar humidifier but I do have a bedroom humidifier and putting it in my bathroom along with the guitar and just letting it run I'm hoping that after a few days of the guitar be properly humidified. I'm never done this before so I've no idea for killing is a good idea lol.

3. I've read the cleats should be made of the same word that the top is made out ofBut I'm finding it very hard-to-find spruce cleats locally. I'm wondering if I can use another crossgrain complete of another wood?

4. I saw video video where they used to clique the entire length of the crack using the Thompson top crack Corrector tool I'm wondering if that's a good idea?

Thanks again for your intelligent thoughtful and detailed suggestions a look forward to your reply, all the best!.

-Bishop
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bishopbautista
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Re: Whats the best method for soundboard crack repair?

Post by bishopbautista »

Do all replies need to get moderated before they post? I just left a long reply and its not here and I didn't want to re-write the whole thing :(
tippie53
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Location: Hegins, Pa
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Re: Whats the best method for soundboard crack repair?

Post by tippie53 »

it is an anti spam process and you may have one or 2 more posts then your totally approved. Sorry but we sometimes have to deal with some not nice people and it is a way to protect the members. Thanks for your support and understanding.
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
bishopbautista
Posts: 5
Joined: Thu Mar 01, 2018 2:07 pm

Re: Whats the best method for soundboard crack repair?

Post by bishopbautista »

I totally understand, ;) I promise to always behave :)

I'm going to delete my question since it doesn't relate to the post if thats ok

I don't see an option to delete entries, but is it possible for you to remove these regarding the moderation process?

Thank you!
Last edited by bishopbautista on Fri Mar 02, 2018 1:11 pm, edited 1 time in total.
bishopbautista
Posts: 5
Joined: Thu Mar 01, 2018 2:07 pm

Re: Whats the best method for soundboard crack repair?

Post by bishopbautista »

OK I got the bridge off, not sure if I cause more damage but I know it had to come off.

Any suggestion on sanding it down before re-gluing. I'm also assuming I should fix the grain cracks first?

Thanks again!

-Bishop
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Diane Kauffmds
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Joined: Sun Mar 09, 2014 8:13 pm

Re: Whats the best method for soundboard crack repair?

Post by Diane Kauffmds »

I know that classical guitars can have a pretty thin sound board at times. If the sound board is in good shape where the bridge sits, just clean that area up. You can level it by sanding or scraping. Clean off the bottom of the bridge, so you have clean wood for regluing. Make sure that the bottom of the bridge is flat, so it makes good contact all the way around.

I like to double check the bridge placement, to make sure it was correct. I even do this on Martin guitars that I repair. You'd be surprised at how many bridges are mistakenly glued in the wrong position. This is an opportunity to correct a mistake if it was made.

I would rehydrate the guitar, get your cleats in and fix any other cracks, then glue the bridge as the last step.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
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