Apologies for starting another thread about end block cracks. I managed to derail the old one with too many questions, so I decided to start a new thread.

My Guild F30's end block is cracked, along with a crack on the outside, of course. It's what seems to be a classic example of this type of crack, as shown here. Frank's page is very clear, however, I'm not sure how you glue the outside.

It seems like both sides need to be done at the same time. The procedure I'm thinking of would be to get titebond on the crack from the inside, the brush some hot hide glue on the outside. Clamp the top and bottom above the crack, then clamp the crack from the inside out, as shown in this picture:

The only thing I'm worried about is that I'm first clamping the top and back, and I feel like I would need them to be able to "bend" in order to clamp the end block properly.

What's the proper way of gluing and clamping the outside crack?

(To be clear, when I say inside I mean this, and by outside I mean this)



P.S. I was at Gryphon last week for the first time. Great store!

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 Eliva,I think you really need to know if the crack is mobile in order to make a plan. If you put a clamp top to back, directly over the block, with some padded blocks to protect the finish, and get yourself in position so you can carefully watch the crack from the inside, as you twist the clamp tighter and looser, you should be able to see if it is changing.

It's easy to imagine someone standing the guitar up so gravity would help the glue penetrate, then smearing some glue on the crack and the glue ran down into the crack, leaving a void behind.

no traces of glue on he outside?

How stuck was the pin? did you have to drill it out or drive it from the inside?

If you can get a Que-tip w/  hot water down on that smear it might help identify what it is.

Any signs of glue on the pin?

If you get the light just right from the inside you can see the crack inside the pin hole. Any glue? Magnification might help.

All glues are very strong if they are gluing wood to wood that is tight. None of them are very strong bridging a gap except Epoxy  but even Epoxy won't stick well to old glue.

An end pin that gets banged puts a tremendous splitting force on the block.

If the sides are still glued tight to the surface of the block and the crack won't close because of a previous  glue, I would consider a patch across the crack on the inside glued with Hide and a cosmetic fix to the outside.

I think that if the endpin was the reason for the crack it would be an out side to inside crack, this appears to be coming from both directions but more prominently from the inside. If it won't close and there's no indication of it on the top and back then it's likely a weather related shrinkage crack. In which case it should be patched with a cleat for the same reason you would use a spline on a top crack.

Hi Dave! Thanks for replying.

I clamped above and below the end block with a spool clamp and tightened/loosened the wing nut. No luck, the crack didn't close or open. HOWEVER, I put a long clamp with one end on the end block and the other next to the neck, just like in this picture. The crack certainly widens inside as I tighten the clamp. So I do not to think the crack isn't glued. Also, it would need inside-outside clamping to close it properly. I could get a spool clamp in there and see if it closes.

With that being said, I cleaned up the block with a moist paper towel, and the glue smears are very prominent now. Here's a picture that can be viewed at full resolution. You can see how the glue was smeared along the beveled edges of the block. Also, is it just me or the left side of the crack doesn't seem to be aligned well? It might just be the angle the picture was taken from, though.

I haven't gotten there with a wet and warm q-tip, but I think this is superglue. The residue isn't the color I'd expect from wood glue, and it didn't leave a film over the wood (like I think epoxy would). However, it seems to be absorbed in the wood.

There are no traces of glue on the outside. The end pin was stuck in there pretty hard. I couldn't get it out by pulling with my hand, I had to get a piece of twine around it and use that to pull. Took a lot of effort to get it out. However, it didn't seem like it was glued in place. It was certainly stuck beyond the point it should have been in.

I think there is glue on the pin. It's not clean, and it seems to have some wood dust on it, but the dust can't be cleaned up by just trying to brush it with my hand.

To put it in fewer words, I believe the crack isn't glued, but that someone did attempt gluing it before (unsuccessfully). I'm eager to hear what is your opinion, John, Dave, Ned, and anyone else who's willing to chime in.

John, there is nothing to restrict the expansion and contraction of the block and sides with humidity changes. I can't see any other mechanism for creating this crack except impact/wedging.  

 Eliya, the cleaned up picture clearly shows a previous repair.

If the glue happens to be Hide,( again not likely put possible) it opens up the possibility of softening the glue with heat and new Hide glue and getting the crack to close properly. This is a difficult thing to pull off. but if it is Hide glue it can be done.

 What purpose would clamping between the inside and outside serve if the sides are not loose from the block? 

The pressure needed, to asses and glue, is straight down between top and back at the center of the block. Not a spool clamp on the outside edge and not a clamp, neck block to tail block, that may be just  hinging the unglued portion of the crack open on the inside.

If the previous glue repair has broken all the way through, you will be attempting a glue on glue repair. That is only effective with Hide glue on top of Hide glue.

 It's still unclear to me if the crack is loose all the way through at this point. If it is, pushing the pin in should open the crack on the outside.

If you are going to attempt filling this crack with anything, (Epoxy, Hide, etc.) wedging it open as far as you dare to get glue in  would be part of the process. The trick is determining if it is broken all the way through without breaking it all the way through.

 Words are mighty cumbersome talking about repairs sometimes.

Eliya, For what it's worth, I just saw your previous post about this back in May. I did not realize this was a first venture into repair (woodwork?). I have to agree w/ Paul Verticchio on this. End blocks are a very remote location to do good work on cleanly, especially if you have to move quickly. You might consider another instrument for your learning or find a local luthier and make some sort of deal with him to be taught or watch over his shoulder.

You can determine if the sides are separated from the block by pushing the side against the block and looking/feeling a void, looking in the endpin hole and seeing if they are still glued there, probing with a thin feeler gauge between the side and the block from the inside, or getting a view of that seam with a mirror or,( what I increasingly use now) a small web-cam.

I agree that this isn't necessarily a beginner's repair, but you also see that I've sat on this for 3-4 months. During this time I gained access to a space with heavy woodworking tools, so I have experience using a table saw, band saw, belt sander, and a jointer. I've also repaired a sunken pickguard on this same guitar and it worked out quite well. That encouraged me to revisit the idea of doing the end block repair myself.

As I mentioned in another comment, the block is most certainly glued to the side.

Lastly, please see my comment on Russell Vance's post. I don't wish to be a nuisance to the members of this forum, nor do I want them to think I'm a threat to them. As I told Russell, I'm here because I have a real interest in this kind of work, and want to learn more.

Thanks again for all your help in this thread.


Sometimes when wood dries out it just cracks there doesn't need to be any pressure on it. It's possible the end block cracked from external pressure put on it.The wedge shape of an endpin would suggest that physics would intervene and make the source of the crack bigger on the outside. But there are no absolutes even when the guitar is in your hands.

As far as looking over a shoulder is concerned, I lose too much of the lucrative regular maintenance work already to the youtube/stewmac apprentices who will do work cheap or for nothing for the "experience ". I get all the work they're afraid of - truss rod replacements and restorations.... Sounds good except that setups and fretdresses used to be the easy money between big jobs. Now it's harder to make a go of it. I'm not picking on you David it's just that the "find a local luthier and make a deal..." Statement is starting to make my skin crawl. 


With all respects, David is doing his best here and offering considered advice:  This crack was very unlikely to have been caused by environmentals.   A drop on the endpin is most likely  I also agree with David that the amount of time expended here to teach a newbie a complex procedure has gone far enough.  

This is straghtforward fix for a qualified repairer with material, wood and glue knowledge and experience but a nightmare for a complete novice.   

I sympathise with the current stress being put on full time breadwinners working in the repair and luthiery industry and as we also run a repair function I am on the receiving end of having to compete with the wannabes and the "work for nothing" crowd.   Encouraging and assisting rank amateurs to conduct repairs that they clearly do not understand just further exacerbates the problem of encouraging your off-grid competition to compete using as their safety net and free (to them) learning pool.  I do not encourage or support running a distant 101 learning facility via already provides a fine service doing just that and much much more.

Those who do not have to make a living from this trade may disagree with me, as is their right.



Rusty, I'm sorry if I barged in to a forum that is reserved for professional. I wouldn't if I had known that it is. I would also like to make it clear that I'm not trying to steal anyone's job, nor am I trying to save a buck. I'm here because and I'm trying to repair my own guitar because I have a real interest in this kind of work. I've been going from one store to the next around Chicago, trying to see if someone need an unpaid apprentice. I'm willing to help around and do the tasks no one wants to do, as long as I can watch what they do and learn some techniques. Everyone's been very nice, but they all turned me away. The only way I can learn more about this kind of work is by reading and asking questions online, then applying what I learned on my own instruments. I'm also strong believer and supporter of sharing the wealth of information. I think it makes us all more informed and better craftsmen, scientists, teachers, doctors, what have you.

As for the repair itself, the technically difficult part (in my opinion), is gluing the end block, and I find it to be very straightforward. I believe I can do that easily using wood glue. It's figuring out how to remove old glue (if necessary), and how to fix the outside of the crack that I'm taking my time thinking about. Again, I'm not a professional, but I'd like to think that I'm taking a professional approach to my studying of guitar repair. I try and be very methodical, meticulous, and thorough, and this is why this thread have been longer than others. I try and understand all the possibilities and angles to this repair. With that being said, I know that it's hard to teach a craft online. There's no substitute to showing (and learning) this kind of work in person; I try to do with what I have.

If the sort of questions I'm asking is frowned upon, then I'll switch to being a fly in the wall.



I appreciate your plight and can emphasize with your predicament.  It was not a personal attack but the observations I made were never going to please everybody.  They may in fact be wrong or inappaoropriate in the spirit of and I will take it on the chin if that is so.

The forum here is for everybody, beginners, amateurs, craftsmen and professionals and as we all know and demonstrate we will get each other out of trouble and do the best to help when problems arise.  There are outstanding photo essays and links provided every other day and we all learn from these.

However, my observation takes into account determining where assistance stops and teaching starts -  The fix is detailed to the n'th degree in (as you have already noted).  Do the fix exactly as detailed by FF and repair the outside in accordance with other sections on repairing side splits found on  You can do both repairs simultaneously if you have sufficient clamps, the right glue and three hands etc.  Do a dry run before you go in and follow the procedure word for word.  

Getting three lots of additional and differing advice just confuses the issue and increases the verbiage here.

Also, my observations about the industry and the extant skill levels are just things I see.  I'm a qualified technician with a factory and a workshop  but I can be easily put out of business by a guy with a hammer and chisel and a kitchen table who works for nothing and will lose interest quickly.    Tough stuff sometimes.


I agree, Dave, writing about repairs is very cumbersome.

My comment about the spool clamp was to thread it through the end pin hole, and clamp down the block. I'm pretty sure the crack is the result of the guitar falling on its butt, meaning that the wood cracked inward, towards the neck. By clamping it this way, I push it back to its natural position. I did that just now, and the crack is narrowing down. You can still see it, but it's closed up a little bit. I larger spool (maybe 2", mine is 5/4") might be able to close the crack even further.

The block isn't separated from the side. I looked through the end pin hole, and I checked with a 0.002" feeler gauge. All these seems are very tight.

I think that whatever repair that was done didn't take. If part of the crack was still glued, then I wouldn't be able to wedge the crack open with a clamp (by the way, this is something I picked up from Perhaps I'm wrong though? I felt like I could tighten the clamp more, to see if the crack opens further, but I was worried I'll expand the crack. I certainly managed to open it enough to get glue in there.

If I attempt this repair, I will not do it with hot hide glue. There's just no way I could get it all in the crack before it starts to dry. Frank Ford seems to use wood glue for these repairs, and that's good enough for me.

I'll respond to your other post and John's post soon. I need to get going.

Here's a rig that will spread and clamp at the same time. You could try it and see if the crack closes up. Be careful not to spread it to much. The long dowel had a hole right through out and T nut on the inside facing the end block, at the other end you have all the workings of a spool clamp. You have to put all the inside peices on after you thread the rod through from the end. 


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