Repairing broken guitar headstock?

[MickCheese]

I would be interested in your opinion.

I have just got a acoustic guitar from freecycle. The head and the nut has been broken off.

The two parts are a fairly good fit so I am confident I can glue and clamp it back together.

Should I use Titebond three or Gorilla glue to do this?

Mick

 

[jimi43]

Titebond Original

If it is mahogany you may find that you will be doing it again though...it's not going to break again on the joint but it may on adjacent grain.

Is this the sort of problem you have?

I have since polished and added the logo but this is pre-polish finished:

In the end I had to splice in a new overlay to stop the mahogany sheering again.

If we can see pictures of your problem we could comment further.

Jim

 

[Kalimna]

Would it be fair to say that, even if it is a clean break the mating surfaces would be less than idea and small gaps may be present?
As PU glues have essentially no gap filling strength, and aliphatic resins like Titebond arent too much better, then my guess would be to use an epoxy resin which will have good strength as well as gap filling.

As mentioned above, a piccy of the 'problem' might help...

Adam

 

[jimi43]

I would agree to some extent with that view Adam...and I have used West Systems on contaminated or poorly retained breaks but if the surfaces push back ok..the aliphatic resin glues will work...

The repair above was done with just Titebond Original once and then sheered again but along a new grain line...the first repair glue joint held fast!

If it is mahogany...this is an accident waiting to happen and I laminated some American walnut on the face and matched it up to help prevent this. So far it has held...and I don't think it is going anywhere now.

I wouldn't use a cheaper epoxy though...West Systems are the only ones I trust now for that sort of repair

Special scarf joints will also work..but are complicated to get right for the uninitiated.


Jim

 

[MickCheese]

Thanks for the replies.

I will sort our a picture so you can see what I mean. The break is not clean but splintered. I see that as a bit of a bonus as it is almost a mortice and tenon.

It is a Yamaha F310 and looks like mahogany.

When I push the two pieces back together they form a fairly good tight join that will only take a little cleaning up.

Mick

 

[MickCheese]

Here are some photos

Placed together

As you can see the previous owner has tried to glue it himself but it failed. The glue looks worse in the photos than to the eye.

Mick

 

[jimi43]

Oh dear...that is very unfortunate....the old glue is going to contaminate the joint to the point where I don't think that it will hold...especially since (unusually) it is a completely radial sheer not in line with the grain.

I can't honestly say that I have seen a headstock sheer like that before.

I think you are going to have to use epoxy...try the West System ones...Axminster sells them but they are not that cheap.

You will probably need to put dowels in to strengthen the joint, I recommend carbon fibre rod.

I have just thought...I may have a Yamaha F310 neck going spare....it's yours if you want it...I am not sure what would be easiest....taking the old neck off or fixing the headstock...I will check to see how and what it is fixed to the body with.

PM me if you are interested...just the postal costs is all I would want.

Jim

 

[MickCheese]

Oh dear...that is very unfortunate....the old glue is going to contaminate the joint to the point where I don't think that it will hold...especially since (unusually) it is a completely radial sheer not in line with the grain.

I can't honestly say that I have seen a headstock sheer like that before.

I think you are going to have to use epoxy...try the West System ones...Axminster sells them but they are not that cheap.

You will probably need to put dowels in to strengthen the joint, I recommend carbon fibre rod.

I have just thought...I may have a Yamaha F310 neck going spare....it's yours if you want it...I am not sure what would be easiest....taking the old neck off or fixing the headstock...I will check to see how and what it is fixed to the body with.

PM me if you are interested...just the postal costs is all I would want.

Jim

Jim

Thanks for the very kind offer. I may yet take you up on this but first I will try a good dollop of epoxy and some cramps.

The break is strange in that there is a lot of glue surface so, providing the old glue does not ruin the joint, I am hopeful.

You were right the West System epoxy was expensive but got some this afternoon. This is scheduled for the weekend so I will let you know how I get on.

Mick

 

[MickCheese]

Hi

This morning I set about gluing the headstock. I intended to use Epoxy but upon reading the accompanying instruction it seems I needed some filler in order to use it as a bonding agent. So rather than waiting (not good at waiting) I decided to use titebond original and see how it goes.

The guitar was free to me and is only about £100 to buy new so I am not practising on a relic.

Here are some pictures.

I cramped a wood block across the fretboard against a fret and used three large rubber bands to the machine heads to hold it tight.

Will leave for 24 hours to see how the joint has taken.

Mick

 

[Setch]

Mick, don't waste time attempting a straight re-glue. It is guaranteed to fail in no time at all, and will make further repair more difficult by introducing mess and dried glue contamination.

EDIT: Looks like I was typing as you were gluing - oh well!

There are several ways to make that repair, but all are time consuming, complex, and would involve more time than an instrument of that value is worth.

However, if you're like me, you'll probably do it anyway for the challenge...

If it were me, I'd scarf on a new headstock, or add a fresh portion with original neck and headstock on either side:

http://galileo.spaceports.com/~fishbake ... /broke.htm
http://galileo.spaceports.com/~fishbake ... broke2.htm

If the instrument was more valuable I'd opt for a less invasive 'back strap' repair:

http://www.frets.com/fretspages/luthier ... erlay.html

Eitherway, use titebond original, or hot hide glue (if you're familiar with it, this isn't a job o learn with!) or good quality epoxy. Don't use titebond 2 or 3 (they will creep under tension) or poly.

 

[MickCheese]

Setch

Too late #-o , and you are right I do like the challenge.

I am considering routing two or three small channels, about ¼"X¼"X2", in the rear of the neck across the joint and gluing in some mahogany filler strips for added strength.

Will see how this comes out and it is good to practice on should my more expensive guitars befall the same fate.

The photo's make this look like a straight break and end grain to end grain join when in fact it is not and there are lots of side grain areas where the glue will have a good chance to hold.

I have my fingers crossed.

Mick

 

[jimi43]

I'm afraid I'm with Setch on this one (out of pure sad experience).

The cheap Takamine that I had to do was free on Freecycle..a lady had given up trying to have it fixed and decided to give it away. I still have that guitar and it is my favourite (until I finish my Martin build sometime in the 22nd Century! )

You can see from the photo below...my break was along the mahogany grain right up to half way down the headstock and because this was a one piece neck....it was going to happen again...

You can just see the first repair to the left of the new break...the Titebond held firm...it's just the nature of these thin neck/headstock transitions. It may look sexy but under string tension...one ding...however light and the grain will sheer.

If I wanted this to be a guitar again...I would have to change the structure of the transition...and this is probably what you will need to do but from the back.

In this shot...the neck/headstock transition is mounted in a quick MDF jig level to enable me to route the entire top end out.

The walnut is then used to give a hard top piece on the headstock and stop the straight grain problem....laminated in place...

You can't see it here but I drilled two dowel holes deep into the neck and inserted two pieces of walnut right in deep....and into the bottom piece of the remaining headstock then put the cap on...

....not a great match...but I was going to stain it anyway....

The final result is not going to win any prizes in the hidden repair category but it was my first attempt and like you said, you can learn on something that will not matter too much if it does screw up rather on a Taylor or Martin which would leave me cold! :wink:

It's been "settling" for over a year now of constant playing....so next time I change the strings...I will match in some vintage headstock binding to finish it off!

My friend in the USA who worked for Gibson...says that this is a common fault with Les Pauls for the very same reason. He would route out two channels on the back....across the transition...bed in West System epoxy and carbon fibre rod (roughed up with 60 grit) and leave space at the top which was then filled in with maahogany patch fillets....and make good.

I think this is your best option...short of replacing the neck.

Hope this helps

Jim

 

[Setch]

I don't think dowels or splines are the best idea for neck repairs, they often remove glueing area in the original repair, and it simply isn't possible to fit them such that they are both perfectly fitted *and* well wetted with glue, and they end abruptly creating a stress concentration which could contribute to subsequent breaks.

The back strap is much stronger, better looking, and gives you continuous long grain across and beyond the break.

You can see how I do it, albeit in this case as a construction technique, not a repair:

http://home.asparagine.net/ant/blog/?p=139

In this case however, I would definately look at scarf jointing in an entirely new head or using a scarf to rejoin the old head.

 

[jimi43]

There are probably as many ways of fixing as there are breaks and each break needs careful consideration as the repair should suit the break.

Dowels and Titebond form a completely integrated joint which will not break...but agree a scarf is one answer. The complexity of some scarfs and the care needed to retain the original neck/headstock geometry is something to possibly work up to. But you are right...probably the best option in this case.

Whatever works that you are comfortable with doing...go for it.

Jim

 

[MickCheese]

Setch / Jim

I really appreciate your help and guidance. I have to keep in mind my own skills and work within them. This will be a chance for me to learn some techniques and try to produce a passable repair that will stand up to use.

My thoughts were to make a jig that will allow me to run two splines into the rear of the neck across the joint and glue in a piece of timber, but I understand that what I will be doing is putting in another piece of straight grained wood with the same orientation as the original so am not improving on an already flawed design. But this break was not along the grain, it appears to me to be caused by a weakness introduced by too much wood being removed for the truss rod hole.

I don't want to get too adventurous and make a complete hash of this and I don't want to do anything that means I do more damage.

I don't think by inserting splines I will do more damage and it is within my capability. I am concerned that the truss rod is not a long way from the surface on this fairly slim neck and don't want to wreck my router bit.

I could try, as suggested by Jim, a couple of dowels epoxied in, would that be a good compromise and strengthen my glue joint?

Mick

 

[jimi43]

As I mentioned earlier...every single break requires a different approach to repair in my experience...and this is an unusual one. You are correct in your diagnosis that the truss rod cavity has indeed compounded the problem which is inherent with one piece mahogany necks.

There is incredible tension on the headstock and this type of construction does not survive well if any kind of bash occurs...particularly a fall.

On the Yamaha, the truss rod is really close to the headstock and this means that the option to dowel is probably not the best one. As for routing...I would probably do spline channels by hand given the circumstances...with a very sharp paring chisel to reinforce the first fix.

Setch's links show a very elegant method of rear splicing and laying down a laminate and this is one option but I feel that you are probably not keen on attempting this at this stage of experience. It is actually quite radical but relatively easy once you try it....why not give that option a go.

One thing is for sure...that joint will fail as it is at present...I think we are both in agreement there.

Jim

 

[Setch]

Whilst I'm not sure splines are the best solution here, I think they are probably the easiest approach to reinforce the reglued headstock. They're also unlikely to prevent you using a scarf joint if they fail, so it won't hurt to try them and see how it all holds up.

If it does fail, the scarf joint approach is not nearly as intimidating as it looks - it's actually a very simple joint, and extremely strong. A pretty simple jig would allow you to start the cut with a handsaw, then tidy it up using chisels and sanding blocks.

 

[Benchwayze]

Not exactly a Gibson is it!

Just whack in a few pocket-hole screws.
A spot of 'elmers' glue; plus a biscuit maybe to be posh and job done.


(homer)

:wink: John

best of luck

 

[MickCheese]

Not exactly a Gibson is it!

Just whack in a few pocket-hole screws.
A spot of 'elmers' glue; plus a biscuit maybe to be posh and job done.


(homer)

:wink: John

best of luck

John

I think you have cracked it, I don't think those other two have a clue! :roll: What do you think?

Mick

 

[jimi43]

:ho2 =D>

At least you didn't suggest duct tape......wait.....that is what was used in the photos! :mrgreen:

Don'tcha just lurve these newly exposed emoticons!

:deer

Jim