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!

Views: 2574

Reply to This

Replies to This Discussion

I understand where you (John and Russell), are coming from, but I find this attitude to be cynical. I think there's a lot of value in developing a mentor-protege relationship, and maybe it's internet romanticism, but I feel like I see a lot of luthiers talk fondly about their mentor or mentee. If someone trained me and then offered me a salary that I can live on, then I'd choose that than starting my own business. Even if I were to start my own business, I'd never take their clients with me. That's such a slap in the face.

John, your advice is good and that's something I try doing. I ask about internship/apprenticeship (whatever you want to call it - training where I'm unpaid), and get told that they don't need anything. I say that I can help with cleaning, running to the hardware store to get something, that I can solder, do easy jobs, can wet sand and polish (no one likes that). I don't expect anyone to show me the ropes and teach me everything, then quit on them a few months later. I just find it a bit cynical (although it might be justified) that this is how you think of possible interns/apprentices.

The advice about saving and doing an accelerated luthiery program - it's a good advice, but maybe for someone who's younger and in a different situation. I'm 27, married, and have a degree in math. If I can't find someone to take me as an intern/apprentice soon, I'll get a job as a software programmer and become a "weekend warrior". At that point I assume it'll be hard to quit only to go to be trained as a luthier. But who knows, maybe I will. I hope I get a chance to learn this stuff before I commit to a full-time day job.

It wasn't cynical at all I was referring to past intern/apprentices not possible ones. As far as lutherie courses go I don't actually think it's good training for a repair person. Builders and repairman do different things. I'll catch some flak for this but I think it's rare that someone is good at both. To me they are two different personalities types. One is a craftsperson and the other is a problem solver. Again even the math would tell you that. Do you want your guitar repaired by the guy that builds most of the time and repairs sometimes or the guy that repairs all the time

You'll learn more by doing than anything else, stop asking questions and start solving problems. It's like math figure it out and then do it. 

Most importantly a sense of humor goes a long way. Sometimes this forum is far too serious.

Watch the video.


Invest 20 years and a million bucks in a business and then address the issue of whether "this attitude" is cynicism or prudence.  

I'm 61 and work in 10-15 year blocks for planning and achievement purposes and do whatever is necessary to obtain goals.  

We own our own guitar factory and run our own repair division - We are successful in both endeavours as they are allied trades and all the equipment and knowledge sets are the same.   I don't see building and repairing as being in any way exclusive providing the process is organised, disciplined  and resources are available.  We have never advertised and have a minimal web presence. Both operations are under the same roof and provide cross business synergy. 

Repair returns are much higher per hour than guitar making and both functions are mutually linked:  when people aren't buying new stuff they are making do with and repairing/updating their old stuff.

My principle mentors are also now long time friends and neither are involved in making or repairing musical instruments,  their expertise is in managing business and sales.   Poor luthiery decisions won't send you broke, poor business decisions or job choices will bankrupt and/or disappoint you. 

If I was 27 again I would get a day job, save up the money to do a luthiery course, take a sabbatical 5 years down track having read everything ever written about luthiery, including all the boring stuff, and do a luthiery course to see if it still rings your bells.  Then work out if you can make a living out of it.

This is stuff that works.





Let me try to summarize a few things as I'm known for not beating around the bush:

To reaffirm Rusty's observation: we are here to assist, not teach. You have received many highly detailed ans workable solutions as well as superior advice regarding other possible outcomes. Try them. If you need assistance once you've started, we're here for that.

Alternately, take your guitar to a QUALIFIED repair person & have them do it. 

This thread of posts has definitely run it's course.

Best of luck.

Like i said a sense of humor and an open mind. When I worked with Joe Kovacic i asked after learning a particularly clever technique, "when do you have it all figured out" he looked at me and pointed his finger and said "Chonny you learn and you learn all your life, and then you die stupid" he's still very funny and probably the most brilliant and prolific builder and repairman I've ever met. 

Just remember our chief weapons are ...A sense of humor an open mind and the last word.... Nobody expects the Spanish Inquisition.

Here is my advise and what I have done. I'm 67 years old, and started doing instrument repairs in the early 1980's with no official schooling or training, no luthier class, ect. I started doing my own repairs on my own instruments because I had a number of instruments, and after sending one off repair I figured I could do my own repairs, just as well.

So, I think, I read every book that was available at the time on how to do various repairs. Then just jumped in and started doing them. A few early repairs I done were maybe not up to top standards, but acceptable. With time, quality improved, and I will say today I'd put my work up against the best repair people in the business. Eventually I started doing repairs for others and have plenty of repeat customers and seem to be getting plenty of new customers, sometimes more than I want.

I do not work for free or even cheap. I charge somewhat less than most shops because I work in my home basement, and by myself. So I can be at home and just head to the basement shop to do work when I feel like it.

I had another full time job (retired now) so repairs were just a hobby job or side job, whatever you want to call it, and I never wanted to go into instrument repairs full time.

I've repair most every stringed instrument made, from upright basses, fiddles, ukes, banjo's, mandolins guitars, dulcimers, ect. Even some electric guitar repairs.

When I first started I had a strong desire to repair instruments and do the best job I could. I think I have done every kind of repair possible, from rebuilding total basket case Martin or Gibson guitars to finish repairs ( not into refinish work though)

I don't build instruments, but have built a couple of mandolins, one uke, and a number of 5-string banjo conversion necks.

Repairing, as mentioned, is much different than building. I like the challenge of the mind to figure out repairs. You need to have a mind to figure things out, and there is normally more than one way to do some of these repairs. You need patience, and walk away from a job to think about it before proceeding. Don't get frustrated and in a big hurry. I also started with only basic woodworking knowledge and a few basic tools.

So you can do this without training or working in some ones shop, you can totally do this on your own. You just need a very strong desire to do this. Start reading, gather some basic tools to start, set up a small shop in your house, collect a few inexpensive instruments to work on or start on your own instruments.

You will be nervous when first starting out, and not wanting to mess things up, but when you make a mistake, think about how to correct it and move on, don't give up. You can do it. Everyone makes mistakes, even the best repairmen.

I was in my 30's when I got serious about doing repairs, so you a young and have plenty of time to learn if you make it a priority.



Thanks to everyone who chimed in on how they got their start. I appreciate it and find it inspiring.

As for the thread running its course, I disagree. First, there's always more to learn - for me and others. In a few weeks/months/years, someone else might have the same problem and will stumble across this thread and find the answers. Moreover, a lot of the posts discussed the meat of the repair (gluing the block), and to be honest, I had a good idea how to approach that before I posted. Lastly, I'd like to think that this thread can easily be ignored. No one has to read it or post in it. However, not all the posts concern the repair itself, so future readers might give up on reading the whole thing. Oh, well.

In the spirit of my last paragraph, let me update on what I've done. Like I said, I suspected that the glue smear is superglue, and I was right. I laid wax paper inside the guitar and also covered the top and sides with it. Then I dipped a q-tip in acetone and carefully inserted it through the soundhole and rubbed it along the crack. Sure enough, the smear rubbed off - it was superglue! My thinking was that some glue must have gotten in the crack, so I had to get in there and rub it off. I clamped the guitar so that the crack was wedged open (towards the inside, of course), and I got in there with a fine brush that I dipped in acetone. I got the brush in the crack (not easy), and moved it along it to make sure I get all the (possible) traces of glue. I probably went in with the brush 4-5 times.I hope I got all the old glue out, but it's impossible to know for sure. I'd like to think that I did.

Now it's time for me to actually start do the gluing and cut the supporting block. However, If anyone has any methods for verifying that all the superglue is removed, I'm all ears!

I'm attaching a few pictures showing what I've done. The second picture shows the block all cleaned up (while the crack is still wedged open). There's some discoloration because of the acetone, but I think it's nothing to be worried about.

Thanks for reading.


I got a piece of mahogany to make the reinforcement patch. How thick/thin do people make those? Frank's piece seems like it's 1/4" thick, or maybe even thinner.

Also, how do people like cutting the bevels? A plane? belt sander? Cutting with a band/table saw, then smoothing out with sand paper?

I'd make the reinforcing patch 1/8" thick, should be fine.

There are many ways to make bevels, power tools or by hand, whatever works.

If you just think about it, and have some basic woodworking knowledge, you can answer many of your questions yourself.

Before you start on instrument repairs, gain some basic knowledge first.


Concerning removing old glue before re-gluing. I don't worry about it, unless it's really a mess, then I'll do my best to clean it, if I can get to it.

In normal gluing operations the glue soaks into the wood, so it's still a wood to wood connection.

I like hot hide glue for repairs because it will melt into old hide glue, and even hold well when a different glue was used originally.

Many times you can come up with your own ideas for a repair, by understanding the basics of a repair and using your own thought process to figure out a solution. You don't have to do it like someone else does, maybe you have a better plan.


I ran into another hurdle today. I was doing a dry run and notice that the crack didn't close all the way (see the first picture) . The second picture shows the end block clamped without the supporting block, since it's easier to see the crack that way.

The clamping was, of course, done through the end block with a 1/2" acrylic caul on the outside, and on the inside I had the supporting block (1/8" thick at the center, made of mahogany) and another 1/2" acrylic caul. I also clamped the top and back with a mini bar clamp right at the seam of the top, and a spool clamp on each side of it, see the third picture. The crack closes, but not all the way. Prior to clamping the guitar had a damp it in it for two days.

I'm going to leave it clamped (again, no glue) for a day or two and hope it'll close, but I'm not sure that'll do the trick. Any ideas why it won't close and how to get it to close?


It's been over 15 minutes so I can't edit my post, but I just clamped the top and back and I couldn't get a .002 feeler gauge in the crack. That makes me thing it actually closes well (yet the crack doesn't "blend" into the grain).


© 2024   Created by Frank Ford.   Powered by

Badges  |  Report an Issue  |  Terms of Service