Official Luthiers Forum!

A friend called me for some help. His Taylor has a hairline crack in the soundboard starting behind the bridge and stopping at the end block. It appears to be right where the soundboard is joined together but it is hard to tell exactly. I used a piece of paper as a feeler gauge and the crack seems to be fairly deep in some locations but is not very wide. For the fix I was considering wicking CA down the crack but am concerned it will make a mess of the top. Once dry I am sure I could level and polish the top where the crack was but still have concerns of the final fix cosmetically.

Any thoughts or ideas?

_________________
Brad
Avon, OH

Reach inside and pry it open, work some hide or white glue in to it, and clamp it shut. If it's not closed tight right now, rehumidify it until it is. Don't try to stick anything in to a crack to check - you're tearing (or at least pushing) small wood fibers out of place that will get in the way of a proper reglue. Just make sure it's remumidified until the crack is tight, then glue it up. Necessity of cleats will be up to your judgement.

_________________
Eschew obfuscation, espouse elucidation.

David...thanks for the quick feedback.

_________________
Brad
Avon, OH

Take a straight edge across the top, is there a dome? please refer to Taylor's video regarding humidity. You will need to rehumidify then get glue into the crack and somehow clamp it up. If you don't feel up to it you should take it to a repair person.

_________________
Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

Is this under warranty? This type of crack is often caused by humidity . You need to rehydrate the guitar before you do anything if the crack is not closed. You won't be able to clamp it closed if the wood cracked from dryness.
Once the wood is rehydrated you can address the crack.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

The guitar is no longer under warranty. I am sure the crack was formed as a result of the guitar being stored in a church where the floor is headed and the guitar is probably very dry. I will re-humudify and then see how things move and address from there.

_________________
Brad
Avon, OH

Not sure if by "pry" David meant to say "push," but that's what I do. With the guitar properly humidified, if the crack is closed, push up from inside to expose the gluing surfaces, apply glue, release from inside, let dry. Then cleat. If the crack line is peaked, you will need to cleat at the same time you glue the crack to flatten it with your cleating system (tuner clamps or magnets in my shop).

Centerline cracks are common, and usually are actually right alongside the glue line; not glue line failure. It's a place where humidity stress concentrates--the two sides of the top both pull away from the center in dry conditions.

_________________
Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

What Howard said !

he 's done many of these !

Mike

_________________
Mike Collins

Check out Bob Taylor intentionally drying out a guitar to the point of cracking, and not being playable.
http://www.youtube.com/watch?v=eusLzn9ZhCE

Then re-humidifying..
Part 1
http://www.youtube.com/watch?v=tB8tELj43RE
Part 2
http://www.youtube.com/watch?v=bWcGdWFiv4M

_________________
Jim Hansen

http://www.frets.com/FRETSPages/Luthier ... crack.html

As Frank does here, clamping the area flat with an acrylic caul on the outside and appropriate caul on the inside is often a good thing. This can be done whether or not you are simultaneously gluing in a cleat.

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

I'd also like to add a little tip. What I do is trace the lower bout out on a 2x4 and cut out that shape on the band saw. Then line the face of the clamping caul you just made with cork. Use those to gently squeeze the lower bout. Never use CA on top wood. It doesn't seem to glue well to spruce and it will surely leave an ugly yellowy glue line. It may also help to get a bit of water in the crack then saturate it with Titebond messaging it into the crack. Use a mirror and check the inside to make sure the glue went all the way through. Acrylic cauls on the top help keep the joint flat.