Repairing small crack on the top spruce

WarnerB138 · November 2017

Hi, I'm repairing a small crack on a guitar that I bought used (see photos). It is my understanding that this crack was not caused by any impact or pressure, but formed due to the wood shrinking/expanding slightly from lack of humidity. As seen in the photos, the crack is along the grain, right along the right side of the base of the neck, and "protected"/held together by the cross braces and neck brace, so it doesn't look like there's any pressure on this crack, just a slight splitting due to atmosphere. Notice also a small turn in the crack along the rosette. I want to ask what the best course of action would be for the repair. I've consulted a luthier friend about it and she said use Titebond, rub it deep into the crack, wipe the top surface clean with wet rag. And install small spruce cleats, one butted along the flat brace inside the guitar (along the line of the crack) and another crossing the rest of the crack closer to the sound hole. Clamp with magnets while the glue sets. Seal with a line of polyurethane. Is this the optimum repair method for this crack? What would YOU do if you were repairing this? Thanks

HCQ · November 2017

It is usually recommended to humidify the guitar first as the cracks might close up a bit. Then follow up with repairs.

GreatBohemian · November 2017

Some year ago I had exactly same guitar and exactly same problem...How is that possible??..I got rid off that guitar soon as I had a disire to play french guitar.I still remember those strong bass and mid sounds which I loved for rhythm,but two high strings never tuned up so it caused me a lot of headaches.Also strong sound.Bad bridge setting...
Today I do play very old guitar which I bought in Lion (but originally from gypsy community of Strasbourg) ...Has many cracks and is very light weight and great set up!..I can say I love her.And yes I don't know her "name".

alton · November 2017

I have the Jorgensen Tuxedo model that has the exact same crack. It came with a black plastic pickguard which I removed in an effort to open up the sound a bit. That's when I discovered the crack, and two small holes that I am guessing were drilled for some kind of pickup system.

And to think that I bought it on eBay as being in "near mint" condition.

Craig Bumgarner · November 2017

I have two views of how to repair top cracks. One is to humidify the guitar well and close up the crack before gluing. This gives the glue a better chance at doing the job and looks nice, but only works IF the owner is committed to keeping the guitar humidified in the future. If not, it will surely crack again, often within a week or two. The other approach is to assume the guitar will not be kept sufficiently humidified going forward. If so, the best thing is to install a spline into the crack. Not as pretty, but more stable if the guitar is not going to be kept humidified.

Cleating a crack with small bits of wood on the underside is a common reinforcement approach, but one has to be careful not to induce more stress risers like the fingerboard. The best cleats are thin, light and either diamond shaped or round so a straight edge of the cleat does not align with the grain in the top.

I'd use Hot Hide Glue or Fish Glue instead of Titebond for both the crack and the cleats. HHG or FG will be less visible in the crack than Titebond but more importantly, the seam can be reglued with heat and fresh HHG or FG if it cracks again. Titebond does not stick well to itself, so if the crack opens up again, the edges will have to be cleaned well of Titebond before regluing and this will surely open the crack up to the point it will need a spine. Also, in spite of all three glues being water based, HHG and FG seem to hydrate the wood less than Titebond. Excess hydration causes the edges of the crack to curl up. If this happens, do not sand it down. Just leave it alone for a week or two and it will shrink back to normal on its own.

WarnerB138 · November 2017

So, I ended up removing and replacing the spruce flat brace (as seen in "underside" photo between the sound hole and truss rod) with a longer one that covers the crack. And sealing the crack with titebond. Although hot hide glue would have been nice, had I had any at my disposal. I also used a spongebag to humidify prior to repair although couldn't tell if it had any effect on the crack. But the crack is sealed and reinforced so it seems good.

Yes, so I got this DG 300 Jorgenson for $600 off craigslist. And, not counting the crack, it's in like new/excellent condition. There are no noticeable signs of wear outside of the crack. It plays nicely, although I think there is one noticeable fret buzz at around 14-16 on the high e. I'll see if a truss rod adjustment will fix that before getting any frets redone by my luthier friend.

And yes the crack was something that I wanted to look nice for resale value as well. Since this will definitely not be my last GJ guitar investment. But for now, it's quite good to play on and sounds (and looks) awesome. And now i'll be sure to keep it humidified at all times.

Thanks!

Bones · November 2017

how did you remove the brace? Was it difficult?

WarnerB138 · November 2017

I used a 2" putty knife, angled it in a vise and thinned the blade end with a sander. lined the sound hole with masking tape. I actually didn't use any heat because my luthier friend said to try removing it without heat first, sometimes they come off easily. It was not easy to remove, but eventually with some finessing and awkward plying it came off in one piece. With no scratches to the finish! So, yes it takes some skill and care. Especially with such a small sound hole. Removing the old flat brace took about 15 minutes.