Crack neck repair job (my way)

lapdawg

I've been wanting to try my hand at a neck repair. As someone who likesGibsons, it goes with the territory. When I saw that Wizard had been given a Tanglewood with a typicalneck / HS crack, I persuaded him to let me havea go. I decided against hide glue because getting the glue right into the narrow crack would take a lot of wiggling. Hide glue gels and sets far too quickly for this.
I chose to use phenol resorcinol. This is an old school wood glue. It was used to fix the maple tops to bodies in theold LP's. The gel time may have been a problem for this exercise as well.
I am going to guess that Gearhead may know more about this glue as it is used in yacht building becasue it is waterproof & has good strength. It als sets to hard and brittle - just what is needed on an instrument.
Here are are some "before" pics.

I made a little balance to mix 5:1 parts of glue. Apparently this ratio mst be very accurate. 1 x M8 nut = 1 part.

After lots of careful wiggling and working with a icecream stick, the crack is full of glue:

Wipe - clamp - wipe - tighten - wipe etc. etc. & leave for 18hrs.

Next, the rough edge of the crack is given a light pass with a scraper & some clear nitro is inked on with a match head. This covers the line left in the repair. Its left for a week to harden and settle.

The nitro is then carefully scraped to level

Following this, a bitof rubbing compound & buffing. All that is left to do is is some finer polishing:

IMO, this guitar is now good to go & should not sound any different or be any weaker than before the break.

Wizard

You're pretty damn astonishing. Enough said.

Psean

Looks great. Nice work!

Chabenda

Very nice indeed Lapdawg. ?

Gearhead

lapdawg wrote: I am going to guess that Gearhead may know more about this glue as it is used in yacht building becasue it is waterproof & has good strength. It als sets to hard and brittle

No experience, I never liked the look of this stuff: it comes out black, which is not so nice for clear lacquer finishes. With this instrument you don't mind since its finish does not mind. In any case, the brittleness is nice for a very thin layer in a repair like this, but filling larger gaps becomes problematic on a highly stressed racing dinghy or instrument neck.

lapdawg

Gearhead wrote:
lapdawg wrote: I am going to guess that Gearhead may know more about this glue as it is used in yacht building becasue it is waterproof & has good strength. It als sets to hard and brittle
No experience, I never liked the look of this stuff: it comes out black, which is not so nice for clear lacquer finishes. With this instrument you don't mind since its finish does not mind. In any case, the brittleness is nice for a very thin layer in a repair like this, but filling larger gaps becomes problematic on a highly stressed racing dinghy or instrument neck.

Its not that pretty, agreed, but I know its used for marine ply because it is very water resistant. Where seams are not seen and where the joint doesn't need to be undone, then its OK.

Nick-le-Rock

Hey lapdawg. Good job on that cracked headstock/neck.

Hi have a few question regarding some of the materials you mentioned.

Firstly....where on earth do you get hide glue. I've been looking and asking at all my local hardware shops for years and no one even knows what I am talking about. Also, where do you buy the phenol resorcinol?
What is the nitro you were referring to on the finishing touches?

Have you ever used a product called Balcotan. I have been using it for about three months on all kinds of neck breaks. The nice thing about this product is that it is has a low viscosity and 1 hour 'pot time'. You pour it into the crack and give it 15min to flow into all the little cracks by itself before you clamp it. You won't need to wiggle it around or go mess with a putty knife inside or anything like that. The bottle says 6 hours dry time, but I tend to give 24 anyway.

Cheers

lapdawg

Nick le Rock wrote: Hey lapdawg. Good job on that cracked headstock/neck.

Hi have a few question regarding some of the materials you mentioned.

Firstly....where on earth do you get hide glue. I've been looking and asking at all my local hardware shops for years and no one even knows what I am talking about. Also, where do you buy the phenol resorcinol?
What is the nitro you were referring to on the finishing touches?

Have you ever used a product called Balcotan. I have been using it for about three months on all kinds of neck breaks. The nice thing about this product is that it is has a low viscosity and 1 hour 'pot time'. You pour it into the crack and give it 15min to flow into all the little cracks by itself before you clamp it. You won't need to wiggle it around or go mess with a putty knife inside or anything like that. The bottle says 6 hours dry time, but I tend to give 24 anyway.

Cheers

I get the the hide glue online. For the most part, granular/ powdered is better than the beads. Shop around on eBay. Using it is not easy. Let me know if you need some tips.
I have also made my own from dog chews - that's cheaper but is a time consuming and careful process in terms of managing heating & drying temperature.

The value of hide glue is that you can undo any joint with steam. This is important for most joints on a guitar. I think a neck break is one exception. The other reason that I have used only hide and Resorcinol is that they both set to a very hard and rigid state. This is very important for acoustics.

I know Balcotan well. I guess it might be OK for a neck break, but I'm not 100% convinced of its acoustic quality. Its messiness might be difficult to manage in some cases.

Nick-le-Rock

The ability to undo joints is precisely why I am looking for hide glue, especially for bridge, body and fretboard repairs. Tips will be much appreciated. Even on making them from dog chews.

Where do you get the Resorcinol? And what is the Nitro you were referring to?

Because Balcotan is so permanent, I only use it on neck repairs. With regards to the messiness, I use the Balcotan cleaner.
Thanks for your tips so far.

lapdawg

Nick le Rock wrote: The ability to undo joints is precisely why I am looking for hide glue, especially for bridge, body and fretboard repairs. Tips will be much appreciated. Even on making them from dog chews.

Where do you get the Resorcinol? And what is the Nitro you were referring to?

Because Balcotan is so permanent, I only use it on neck repairs. With regards to the messiness, I use the Balcotan cleaner.
Thanks for your tips so far.

I eventually managed to find the Resorcinol at a glue place in Epping. I will PM you their details & will check them at home this evening. I'll also send you details of the "nitro" I use this evening. I use 2 types of nitro - one that is bought & has platicisers etc. & one that I mix up for vintage stuff from NC solids - its brittle & gives the cracking etc. found on vintage instruments.

Nick-le-Rock

Thanks. I look forward to that PM!

singemonkey

Fine work again Lapdawg.

Skylark

I know about Resorcinol, my father built a boat and used it widely, very strong and hard wearing. He bent some laminates through 90 degrees with steam and then glued them up with resorcinol, 35yrs later the glue joints were still good as new and perfectly stable.

lapdawg

Skylark wrote: I know about Resorcinol, my father built a boat and used it widely, very strong and hard wearing. He bent some laminates through 90 degrees with steam and then glued them up with resorcinol, 35yrs later the glue joints were still good as new and perfectly stable.

Thanks. Nice to hear that. Sounds like the right stuff for this job.

RamiroPriolo wrote: it's so perfect! lucky to have you!you saved your guitar!!

Thanks - fixing head stock breaks is box I have wanted to tick for a while. If anyone else has a candidate.... Let me know.