Crack in top that needs a splint

[Justin]

Hello again,

 

I have another problem that I would like to get some suggestions about. The problem is I have a guitar in for repair that has a split top, right down the center seam. I have fixed many cracks, but I was able to get them to close up really well with proper humidification. This guitar has such a wide crack, that I'm going to have to splint it...This is a new thing for me. Please let me know how you guys would approach this problem.

 

Thanks

Justin

[Paul Breen]

Before going to more drastic measures, first try wetting (not dampening) the underside of the top using a paintbrush on either side of the crack a good 3 or 4 inches. I've had decent luck with this in the past when humidifieying doesn't do the trick.

[Howard Klepper]

As with most supposed "center seam" cracks, this is not a separation of the center seam at all.  It's a wood crack.  What's the white stuff in it?  How have you humidified?

 

It's called a splint, BTW, not a spline.  And it is one of the hardest things to get right on a guitar, especially the cosmetics.  You can find instructions in Dan Erlewine's repair book, and Irving Sloane's "Martin" repair book.  There are some online sources.  All of them are inadequate in explaining how to match grain, chatoyance, and finish; mainly because this comes from experience. If it is a valuable guitar, I recommend that you pass until you have done this a few times on inexpensive guitars.

[William F.Eden]

 If i had this Guitar I would take the bridge off first then I would set up a strait eadge on ether side of my Dremal tool right down the centre of the crack so as to keep it from moving from side to side.I would use a 3/32nd router bit if that is big enoff to clean up the crack and i would make my starting point over were the bridge would cover any damadge i may do getting the cut started and then make your self a pice of spruce to glue in the space.I WOULD not wet the inside of the top as you will just cause the top to cural up  and you are never going to get it closed tite shut  that  way because some of the wood is already missing. Good luck Bill.''''''''''''''''''''''''''''

[STGuitarworks]

Hi Justin,

Ive had that kind of repair in a couple of times.... well more than a couple. The process that I have used:

-Using a very thin exactoblade (I will thin the blade further using sandpapers) I would clean out and even out the crack.

-I then saturate the crack with water (to simulate how the crack will swell when saturated with wood glue). I repeat this 2 or 3 times.

-Table saw your spruce spline (maybe a couple, they break easily). Sand to a gentle taper so that it fits, hit it with water to raise the grain, let it dry, sand, water, dry and sand to 320grit. Then glue it in, dry, cut it down so that its a bit shallower than the surrounding area. Colour match (if natural) using a strong cup of tea. If high gloss I use cyano.

Hope that helps 

[Paul Breen]

I WOULD not wet the inside of the top as you will just cause the top to cural up  and you are never going to get it closed tite shut  that  way

 

This method does work, any tendency to curl can easily be controlled with flat clamping cauls. A bigger problem for this job is getting the white stuff out of the crack, is that stuff polish or wax? 

 

Here are pictures of a 72 D35 with a bad crack from a shrinking pick guard, you could drop a penny through it.

 

The area is whetted, in this case above and below the top. Then flat cauls are used above and below the top and things are left to dry. (I have done minor cracks though without using cauls at all. Leave a bit of a margin of dry top directly next to the crack, 1/8 or 1/4 inch and keep the crack dry.) The process is repeated until you can't get any more out of it. 

 

Here is a view from inside, the small brace has been removed to accommodate the caul.

 

And a final shot with the crack repaired - NO splint used. The original pick guard was missing and I ended up making a slightly over sized one to hide any cooties. 

[William F.Eden]

 Paul   please read the rest of the sentence. The reapair you did on the D-35 is not the same as the job at hand . I don't think the man wants to take the braces a part on this repiar and it would be kind of hard to clamp all the joint on each side of the center to stop them from curling be sides there is some of the wood already missing   by the way you did a wonderfull job on the D-35   .BILL.'''''''''''''

[Paul Breen]

Bill, thanks for the kind words on the D35 job. I did read your whole post, you seem to think some wood is missing from the split and it can not be re-hydrated to close it. I am simply demonstrating that top whetting can potentially close the center seam crack pictured and some that are worse, like the D35. There are no guarantees or absolutes here but it is certain that putting a splint in there is far more invasive and has a high potential for an ugly repair. Other methods should be exhausted first before such drastic measures are taken.

 

The curling isn't as big a problem as you are speculating, I've done this without clamping anything flat. The D35 pick guard area was badly curled from the pick guard damage and needed some extra help to flatten it. The brace was already hanging by a thread from the damage so it was easier to remove it. If one was concerned or extra careful, you would only need a plexiglass caul on the outside and light clamping in a couple of spots against the spruce inside.