Fixing end block crack - how? and should I do it myself?

[eliya]

Hi everyone!

I recently bought a 1980 Guild F30 that I like a lot, but it has two cracks that need repairing. The worst one is the end block. Seems like the guitar took a fall sometime and and the end pin got pushed in, and now the side around the pin is cracked and so is the end block.

I read Frank's guide on fixing such cracks but I have a few questions.

First, is it possible that the side got detached from the end block? Is there a way to check that?

Secondly, Frank's guide doesn't mention fixing the crack on the outside. Do you use wood glue for that? Hot hide glue? would that crack be fixed simultaneously or after the end block crack is fixed?

Frank says "First I spanned the entire guitar and clamped the crack inward". I assume this means clamp the two ends of the body, pushing the crack to open on the inside. Is that correct?

I was told to first bring the guitar's humidity to 45%. I assume that's necessary so that once I remove the inward clamping action, the crack would close on its own. Correct? What happens if the crack doesn't close well on its own? Is 45% enough or should I go higher?

How much of an effect on the sound does fixing the crack has? I like the guitar the way it sounds right now, so I can only assume any changes in sound would be for the better, not worse.

How silly is it for me to attempt fixing this myself? It's not a matter of frugality as much as it is a matter of me wanting to learn more about guitar repair. So far it seems like the hardest parts are 1) making sure the guitar is humidified enough so that the cracks will close by themselves. 2) dislodging the end pin. 2) Making the mahogany patch. I assume it requires some chiseling, but should the beveled edges be of any particular dimensions and slopes?

I apologize for dropping all these questions, but I like (or at least try) to be thorough.

Thanks!

[Ned Knepp]

Good Morning Eliya,  It probably seems like the mantra around here but pictures of the damage would help a lot. We can't see what you see. 

It's a long way to the tail block but you should be able to get a peek of the edges of the block with a light and mirrors. It's also possible to rig a rod with a thin blade attached to the end ( at an angle) which you can try to slip under the block. You're going to need some way to get glue into the cracked block anyway so rigging something now can benefit you with checking for gaps as well as effecting a repair.

 You should also look at the outside where the sides meet. Is there any sign that that sides are puckered out along the center seam? Is the curve around the body even and the center seam mostly flat?  What you're looking for is to see of the sides may have remained attached at the edges of the block but broken loose where they meet in the center. Tapping on this area can sometimes help you hear a pocked where the block and side are separated. 

Getting the guitar to 45% humidity is to insure that the wood is at a good moisture content level. It's not a guarantee that the crack will close tightly. If the wood was in any tension before it cracked it's probably not going to close up completely without help. On the other hand, it's possible that it will close up and only need to be glued. I would still figure on clamping things up even if it appears to be tight. 

If you click on the pictures next to Frank's explanations, you can get a larger picture so you can see what he's talking about. The clamping he did was from the center of the tail block to the top of the body next to the neck. Notice that he left the end pin in place to help wedge the block open. By putting pressure on the center of the tail block he was able to slightly push the crack across the center of the block inward, toward the sound hole just a bit. Be careful not to over do it. You're trying to open the crack a bit on the inside not split the sides more than they already are. This should open the crack across the block enough to be able to work glue into the block. Once you release the pressure the crack should close up with the glue inside. I would probably remove the pin and clamp it with the clamp located  on the top and back of the guitar, centered on the tail block. 

It looks like Frank used Titebond or something very like it for this repair which is probably because this requires longer working time than hot hide glue will afford. It also not a "sonic" repair as it's not going to effect the sound at all. Even the cracked sides shouldn't have any discernible effect on the sound of the guitar.

 I can't comment on how I would go about repairing the side cracks in any useful way because it depends on how extensive the damage is in that area and I don't have any idea of how extensive this is.  

[eliya]

Thanks Ned!

I'm including a picture of the crack. It only shows one side of the crack (the crack spans both sides of the end pin). I'll upload a better one later.

I'm getting some mirrors I can insert inside the guitar to see how things are looking. So far, if I bring my head very close to the top so there's a very shallow angle between my eyes and the top, I can see the cracked block. From what you wrote it seems like you suggest I get a mirror so I can see the side of the block. Any idea how to do that? I assume it'll require at least two mirrors - one sitting flat inside the guitar, one held at the side of the block, but angled, so I can see the reflection in the first mirror. I'm also going to do what Frank does and solder a palette knife to a steel rod so I can reach inside the crack with glue/ check cracks.

The seam seems ok. I put a straightedge on top of the seam and it touches in two-three points. Two of them are halfway between the pin and top/back, one is in the middle. I put a ruler on other areas of the side, and they have the same flatness to them. So I assume the sides are attached to the block still. However, the pin got wedged in a little by the fall the guitar took (not by me, by the way). Is it possible that the pin being pushed inside separated the sides from the block?

Any advice as to how to remove the pin when it comes to it? It seems to be lodged in there pretty good.

[eliya]

Here's a better image which spans the entire crack.

[Paul Verticchio]

Based upon the questions you are asking, I think the best and only advice we can give you is to take it to a pro for repair..

If pulling an end pin is a 'question', I infer that the tasks required for satisfactory execution of this repair are beyond your skill set. 

These skills are best practiced upon 'yard sale specials', not on an instrument of the quality of the one you have.  This type of repair, especially if the sides have separated from the end block (your theory?) is very advanced repair work.

However, if you wish to attempt the repair to the instrument yourself, realizing up front that a botched repair could ruin the instrument or take some serious $$ to correct by a pro, I'm sure you'll receive instruction from other forum members.

Best of luck getting that nice acoustic back in fighting shape :)

[eliya]

Thanks Paul! I definitely wanted to hear some opinions like yours. I know this is a repair that is beyond my skill set (which isn't very large to begin with), and I want to see if I should try and get some practice repairing guitars starting with this crack.

This is also why I asked a lot of questions - I want to make sure I know everything that goes into what this repair is going to require so that I can then see if I should attempt it myself or not. At the very least, I will learn how to identify what kind of a crack this is and how it should be fixed, even if I'm not the one who's going to fix it now.

Pulling the pin is a question because it got pushed inside and I'm not sure how to dislodge properly. It wouldn't have been a problem if it didn't get that far in.

As far as the sides separating from the block. I don't know that it happened with this guitar, but I want to know how to identify it if it were the case.

Also, I want to apologize again for asking these rudimentary questions. I know this is a forum for working luthiers and not beginners, but I haven't found a better source for beginners like myself. And again, thank you for your response, taking the guitar to a professional is definitely something I consider.

[Paul Verticchio]

You're welcome. The questions you ask are valid. We're here for ALL folks interested in quality repair work, not just for experienced guys. I'm sorry if I came off a bit terse with that reply.

Although we always don't come away with the answers we 'want', we always leave with the best answer for the individual instrument.If this were a Harmony or entry level Yamaha, I'd offer advice to give it a go. However, what you have is a quality instrument that deserves experienced attention. You can take it form me, it's heartbreaking to mess-up a nice guitar due to inexperience. I goofed up a couple in my early days and I'm still embarrassed about it.  I'm not eager to see anyone share that experience.

You are asking good questions and you definitely exhibit a growing passion for the craft. We're here to support that passion. It's our privilege to do so.

Btw: when you're finished and it's sounding & looking good, could you post a full body shot of the Guild? As you may have noticed; we love photos.

Have a great week and best of luck :)

[eliya]

Here's an update. I got some mirrors inside, but I actually snapped a pretty good picture of the end block with a small camera. It seems to me like it had been repaired before. The camera might not show it as well, but there's definitely glue smeared along the crack. The crack itself seems stable, but I don't think the repair was done right because the crack is visible beyond just a "seam" (see the second picture).

This is unrelated to this thread, but the third picture shows one of the braces, and the wood along it seems to be brighter. Does this mean that brace had been reglued (and not in the right spot)?

Between all that and the wrinkled top, I'm thinking I should return it.