Jump to content

Noooo! :-( ... Broken Headstock


Recommended Posts

Everything was going very nicely with my project (a neck through), with no issues what so ever so far. I'd just got everything glued together nicely and was onto sanding when I went and knocked the guitar of my workmate and broke the [insert expletive here] ing headstock.

:D:DB)

It's not broken off completely, its just cracked along the scarf joing glue line, as in this diagram:

headstockbreak1wt.jpg

Just the red bit is cracked, and from what I can see when I carefully prise it open, its not cracked directly along the glue joint, which I was pretty sure was a good joint.

What shall I do?

My best idea was to prise it open and pour some thin CA glue into the crack... could that work?

Thanks

Link to comment
Share on other sites

Thanks Robert,

I have epoxy too, but the CA is a lot runnier and I thought it may penetrate further into the crack

A more extreme method might be to take the whole headstock back off then stick it back on properly rather than trying to drop glue into the joint.

I cant really see how I could do that without removing the fretboard, which would be a major PITA.

Link to comment
Share on other sites

I'm not sure you got a really good glue joint, usually the glued area is stronger than the wood, so it should have cracked anywhere except there. What kind of glue did you use? How long did you let it dry? It sounds like you got in a hurry, and didn't leave it clamped up overnight. Patience is still the key.

Link to comment
Share on other sites

I'm not sure you got a really good glue joint, usually the glued area is stronger than the wood, so it should have cracked anywhere except there. What kind of glue did you use? How long did you let it dry? It sounds like you got in a hurry, and didn't leave it clamped up overnight. Patience is still the key.

+1

I would dampen the glue joint, undo the headstock, let dry, clean, reglue, clamp and wait at least 48 hrs before attempting any work.

If you don't want to undo the headstock, use this glue (http://www.leevalley.com/wood/page.aspx?c=1&p=30261&cat=1,110) . Better than CA/Epoxy this this kind of repair and holds up extremely well.

:D

Link to comment
Share on other sites

I used PVA, and I did leave it clamped overnight (and then some). It's hard to describe, (and impossible to photograph) but when I look inside the crack it seems to start at the glue joint, but its not a clean break along the glue joint. Its not a huge crack either, but its significant

The fretboard is glued to the neck with epoxy, which may mean that I'd need to use heat if I were to remove it.

Here's a better diagram:

breakdetail24sr.jpg

the lump is a veloute thingy.

I'll see if I can get that glue in the UK because I dont think they can send glue from the US by air.

I am tempted to try easier methods before I remove the headstock. With the oil finish I am planning it wont really be any more of an issue to remove and repair the headstock once the guitar is finished if the easier repairs fail.

Thanks!

EDIT: Added glue labels to respective parts on the diagram to make it clearer. Red line is break

Edited by Ben
Link to comment
Share on other sites

They have the chair doctor glue in the UK on the internet. I'll check locally first though to see if I can save on postage.

Link to comment
Share on other sites

If you are sure it isn't the glue joint (maybe it started there) use Titebond (or similar) glue and flex the joint slightly. Very slight. That works it into the crack. Clamp, but not to hard, because that starves the glue joint of enough glue. If it's just the wood that's cracked, then the break should be clean with no pieces of wood missing.

Once dry I would put reinforcement strips. That might be a problem if it will be a clear finish and you have fancy wood for the neck stock.

The strips would span the break and be about 1/4"+ deep.

Glue on top of dry glue is not a good bond. Epoxy might be a good answer as it bonds to almost anything, but to old glue is still a question.

This problem you had made me decide on MY scarf joint.

I will opt for the joint at the peghead with a veneer to reinforce the grain runout.

Is there a picture of the crack?

Hope we are helping.

Mike

Link to comment
Share on other sites

Flex the crack open, and work in Titebond using gravity and a small spatula. Get it as deep in as you possible can, then close up the joint and squeeze it. Clean away as much squeeze out as possible, then clamp it tightly and let it dry for at least 24 hours.

If you find the titebond too thikc you can thin it a little with water, but only a tiny amount, or you'll compromise the strength.

Link to comment
Share on other sites

If you find the titebond too thikc you can thin it a little with water, but only a tiny amount, or you'll compromise the strength.

Bad advice! Thinning the glue with water will weaken the bond. Use the right product. The chair doctor glue is better than CA or epoxy for cracks like this one.

Link to comment
Share on other sites

If you find the titebond too thikc you can thin it a little with water, but only a tiny amount, or you'll compromise the strength.

Bad advice! Thinning the glue with water will weaken the bond. Use the right product. The chair doctor glue is better than CA or epoxy for cracks like this one.

Sorry, but why would that be? Chair doctor works by swelling the wood, doesn't it? Titebond is tried and tested, and I wouldn't start using a product designed for ill-fitting furniture joints on something critical like a headstock.

No offence.

Link to comment
Share on other sites

Thanks everyone,

I tried to measure the crack size when I flex it open [as much as I dare to], and the 0.002"/0.05mm feeler gauge just fits in it. I doubt that PVA would penetrate into it much without thinning, and the epoxy I have is quite thick (can you get thinner epoxy?), so thats what led me to think CA may work. The CA I have has a needle on the end too that with a bit of force may fit into the crack.

The scarf joint is still quite rigid, it takes a fair amount of force to flex the crack open. I would guess that it would hold up to string tension as it is (I have an acoustic with much thinner wood at the headstock, which [with no strings on] flexes more than this one does)

I tried taking a photo, but the size of the crack is too small, and my camera is poor at taking close ups. The photos show nothing at all.

Once dry I would put reinforcement strips. That might be a problem if it will be a clear finish and you have fancy wood for the neck stock.

Not a problem, I'm pretty new to building and it has plenty of visual imperfections already, however considering the size of the crack, the reiforcement may be more trouble than its worth. My wood is from an old table, so its definitely not fancy.

Would that extra info change anybody's advice? do you still think I could get the PVA / epoxy to penetrate into such a narrow space?

Thanks again

Edited by Ben
Link to comment
Share on other sites

If the crack is that small and you're having to put that much preasure on then maybe CA might be strong enough....CA forms good bonds with flat surfaces so I should think its gotta be pretty flat inside that crack with no gaps. I don't think you'll be able to get much else in there due to the small size. The only problem I can forsee is that CA can dry very fast and if you're not quick in getting the glue in there and quickly closing the crack again it might dry with the crack spread open.

Robert

Edited by Robert_the_damned
Link to comment
Share on other sites

Thanks everyone,

I tried to measure the crack size when I flex it open [as much as I dare to], and the 0.002"/0.05mm feeler gauge just fits in it. I doubt that PVA would penetrate into it much without thinning, and the epoxy I have is quite thick (can you get thinner epoxy?), so thats what led me to think CA may work. The CA I have has a needle on the end too that with a bit of force may fit into the crack.

The scarf joint is still quite rigid, it takes a fair amount of force to flex the crack open. I would guess that it would hold up to string tension as it is (I have an acoustic with much thinner wood at the headstock, which [with no strings on] flexes more than this one does)

I tried taking a photo, but the size of the crack is too small, and my camera is poor at taking close ups. The photos show nothing at all.

Once dry I would put reinforcement strips. That might be a problem if it will be a clear finish and you have fancy wood for the neck stock.

Not a problem, I'm pretty new to building and it has plenty of visual imperfections already, however considering the size of the crack, the reiforcement may be more trouble than its worth. My wood is from an old table, so its definitely not fancy.

Would that extra info change anybody's advice? do you still think I could get the PVA / epoxy to penetrate into such a narrow space?

Thanks again

Use Titebond or similar aliphatic resin glue, flex the neck to work it in.

Link to comment
Share on other sites

If it's a tight fitting, long grain break, titebond or hide glue will produce the strongest repair. Hide glue is going to be a beast to get into the crack before it gells, so titebond it is.

You'd be surprised how easy it is to work glue down into a joint. Flex it open as much as you dare, and use a feeler gauge or other thin applicator to push glue as far down as you can. Flex the crack open and closed, and the glue will get pulled in by capilary action. Push in more with the feeler gauge, Flex it again. Blow down the crack as hard as you can. Flex it some more.

etc.

When you feel you've got the glue in as far as it's going to go, squeeze it tight, wipe away the squeeze out and glue it up.

The problem with CA is it's brittle, and will start to cure before the joint is aligned and clamped - this will stop the joint closing up, and this in turn will force the glue to gap fill, which will produce a weak joint.

Titebond will give you a good open time to work it into the area where it needs to be, and plenty of time to get the joint clamped up tight. It's also less likely to stain the wood around the joint, and infinitely less likely to end up glueing you to the guitar!

Sorry, but why would that be? Chair doctor works by swelling the wood, doesn't it? Titebond is tried and tested, and I wouldn't start using a product designed for ill-fitting furniture joints on something critical like a headstock.

Exactly. Swell that joint and you'll never get the damn thing closed up! Titebond will swell it a little, more so if you thin it a touch, but chair doctor is specially formulated to swell the wood *and keep it swollen once it dries*. Not what you want on a joint which is tight and perfectly suited to repairing with conventional wood glue.

Ben, did you feather the joint out so that the end was paper thin, or did the joint end at a 'hard' corner? This makes a big difference to the stregnth of a scarf joint. The feathered end will 'spring' with impact, allowing it to flex with the glued on headstock. A hard corner will not be able to bend, and so will want to crack open. I supect this happened with your joint - the corner allowed a crack to start, which then ran out into the grain because the rest of your glue joint was still solid.

Link to comment
Share on other sites

OK, im going to use the PVA. I'll get to it once I've finished this post.

Ben, did you feather the joint out so that the end was paper thin, or did the joint end at a 'hard' corner? This makes a big difference to the stregnth of a scarf joint. The feathered end will 'spring' with impact, allowing it to flex with the glued on headstock. A hard corner will not be able to bend, and so will want to crack open. I supect this happened with your joint - the corner allowed a crack to start, which then ran out into the grain because the rest of your glue joint was still solid.

Its sort of a cross between the two if that makes any sense. It does go paper thin at the end of the transition, but there is a definite corner, which may have acted as the point of weakness for the crack to start at.

Thanks

Edited by Ben
Link to comment
Share on other sites

I have had good success repairing cracks just like yours.Use whatever glue you feel comfortable with but make sure it is not to thick.Get a friend to put as much pressure on the crack to open it as possible and smear the glue into the joint with your fingers and then blow the glue into the joint with a straw or compressed air.This will make sure the glue hits all of the gluing surface.This works on cracked necks well as long the fretboard shows no damadge.Clamp lightly and wait 24 hours.I use regular yellow wood glue and have never had one fail yet.Rich :D

Link to comment
Share on other sites

phto03362hv.jpg

Told you my camera was crap :D

What you are seeing is beads of glue aroung the edge of the crack.

I clamped the guitar body upside down to my bench, then used another clamp on the back of the headstock to carefully apply constant, controlable pressure to it and prise the gap open [no friend handy :) ]. Then I applied the glue and used the feeler gauge/ blew hard on it to force it in, flexed it etc. I then wiped all the excess glue off, and the pic above is the squeezed out glue from when I removed the clamp [so I'd guess there was more than enough in there].

When sticking the feeler gauge in I could feel the depth of crack, and it wasnt really that deep.

Because I couldnt clamp it easily due to the difficult shapes/ angles, it's now drying in a spare room upstairs with some carefully positioned books applying pressure to the joint.

I'll leave it there undisturbed until monday evening at least.

Seems to have worked well!

Thanks! :DB):D

Link to comment
Share on other sites

Hope that it works out for you Ben. For the unfortunate one that in the future has the same problem and searches for a solution:

I'd definitely have used thin CA. I have glued up a mandolin head crack pretty much like yours with CA and it still holds up perfect. Remember that a mandolin has much higher string tension (counting all strings) than a guitar. CA has some definite advantages over the other glues for this type of crack.

-It is the only one that will reach all the way into the crack (without flexing an already weakened joint). With this type of really delicate crack it is necessary to get good glue penetration.

-It will not degenerate from heat or thermoplastic creep

-It adhere to any type of old glue that you have in the crack already

-It doesn't contain water that might give you problem with swelling wood

The CA will not start to cure until you put pressure in the crack if you work reasonably fast. Just do a couple of dry runs with your clamps so you know exactly how to do it.

For some interesting facts about glue in guitar repair have a look at Frank Fords www.frets.com He's a strong advocate for hide glue but for this type of repair I think that he would choose CA.

Link to comment
Share on other sites

Well I'll be using an oil finish on it, so if the crack re-opens any time in the future, its not like it will be hard to touch up the finish over the repair, as it would be with laquer.

If the crack ever does reopen maybe I'll try CA, but I'll cross that bridge when/if I come to it. Hopefully I never will.

Edited by Ben
Link to comment
Share on other sites

I still can't see a well made scarf joint that was clamped correctly and had time to dry, having this type of problem. You claim you let it dry overnight, so that just means it either wasn't prepared correctly, clamped correctly, or glued correctly. You did you Titebond right? Was your scarf joint smooth and flat on both pieces of wood where they join? These are the type of questions you need to answer before you make any more necks. I would have heated and taken the scarf joint back apart, fixed it, glued it and clamped it back together again, even if it means removing the fingerboard to do so. Since this is a new build and not a repair, but that's just me. I'd want to be certain that there would be no problems down the road with the scarf joint. You probably did a good job and won't have any problems though.

Link to comment
Share on other sites

They don't sell Tightbond round here anywhere I've looked, but the PVA I used should be pretty much the same thing.

I thought I did the scarf joint well, the surfaces were both planed flat, I spent a long time on it because I was aware of how critical it is to get a strong joint.

I was pretty sure I clamped it well too, I drilled holes and used tooth picks (in places that would be removed when I carved the neck) to make sure it wouldnt slip, then I used some of the scrap wood to make what I think is called a 'caul' [?] to match the angle of the headstock when clamping.

Because I wouldnt understand what I just wrote if I were reading it, heres a diagram:

clamp1yj.jpg

If the worst does happen and it breaks in future I'll worry about it then. I may as well try the easier repair first.

If it fails later it wont be much [if any] harder to fix then than it is now. Its not like I'm selling the guitar, (its not like anyone would buy it either :D ), its just for myself.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...