Epoxy on a bad glue joint?

[Gyoon]

I am working on an instrument that has a fingerboard that has become partially unlued (from the nut to the 7th fret, the fingerboard is literally flapping off) Cleaning the glue off hte undersideof the fingerboard is a dicey proposition, considering I don't want to break it (delicate due to the fret kerfs), besides the customer doesn't want to pay much for the repair.

I was thinking about just knifing in some epoxy. I have heard that eposy can join most two surfaces together, unlike white/yellow glue where the two surfaces must be cleaned up. Thoughts?

[62bass]

It might work and hold well enough. It also might not and you'll be left with more to clean up for a permanent fix. Tell the customer to do it right or accept that the cheap fix might not work.

[pkr2]

Originally Posted by Gyoon

I am working on an instrument that has a fingerboard that has become partially unlued (from the nut to the 7th fret, the fingerboard is literally flapping off) Cleaning the glue off hte undersideof the fingerboard is a dicey proposition, considering I don't want to break it (delicate due to the fret kerfs), besides the customer doesn't want to pay much for the repair.

I was thinking about just knifing in some epoxy. I have heard that eposy can join most two surfaces together, unlike white/yellow glue where the two surfaces must be cleaned up. Thoughts?

It all depends. Value of the instrument. condition of the old glue that you plan to leave in the joint, kind of glue that was originally used.

If the old glue has broken down, I wouldn't reglue it without cleaning the surfaces at least enough to level both durfaces and then blowing the joint out as much as possible with compressed air.

There's a lot of shear stress on the FB to neck glue joint so you need a glue that wont "creep" over time. As strong as epoxy is, it wont be any stronger than the bond to the old glue. If the old glue is oxidized and kind of powdery on the surface, I wouldn't trust it with any glue unless it's at least cleaned up on the surface of the failed joint.

If the repair doesn't come out as well as you hope and you have to redo it, epoxy will make it a bear to ever get apart again.

Another thing to consider is that you are leaving a whole lot of glue in that has already failed where the joint seperated so the rest of the glue must be near failure too.

I would either R&R the fingerboard and repair it right or I would pass that job up. If it fails, you can bet that regardless of what you and your customer work out between each other, your reputation as a repairperson could easily be damaged.

IMHO

[Frank Martin]

Don't.
Once you apply epoxy, you can't get it off again (at least it will be much harder).
Take a thin knife or some other metal object, slip it in at the nut between the fb and the neck, and then pull it towards the bridge. If the old glue is as weak as at the first frets, it should come off easily.

[Eric Moesle]

I'm troubled by the original post. He says this is for a "customer" and he's "heard" that epoxy can be used to bind two surfaces.

Its clear from this information that this repair is way over his head and that he shouldn't attempt it for a fee. Refer the customer to a qualified repair shop or luthier, don't attempt to hack it yourself. This kind of repair takes skill. If you try to save the customer a few dollars by attempting it yourself, it will end in disaster and the customer will not be happy and will hold you responsible.

[Gyoon]

The instrument is about $200 in value and is from a company that, for a short period of time in 2003, made a batch of instuments using a glue formula that was faulty. (no names) As a result, there are many acoustic guitars with loose braces, lifting bridges and such. I have never seen one of these with the whole fingerboard lifting.

This company is not doing warranty work on these instruments because it is past the one year warranty period. Having seen warranty repairs come back, I am shocked with the incompetency of some of them. Eric, if you suspect that I may not be qualified, then you should check out the work of these guys. It's like they didn't give a rat's behind. It's as if they had 15 minutes to reglue a headstock or reglue the bridge. (actually, this is probably the reality in a warranty service shop)

The condition of the dried glue was fine actually. The fingerboard has an almost "raw wood" quality to the underside and the mating neck surface isn't too bad.

Here's what I think the required, proper way would be to fix it:

Remove fingerboard

Clean the mating surfaces

Glue fingerboard on (a little tricky because the fingerboard is twisting slightly to the drivers side)

Deal with the slight discrepancies in the joint between the fingerboard and neck edge. Touch up the finish to the best of my ablilities

Deal with the frets (i.e. possible fret job, re-hammer loose frets, fret dress)

Whew! Am I missing anything? I guess some of you would have removed the neck to make a respray possible. I'm not equiped for that.

This is over $700 in work, at least. This is 3 and a half times the cost of the guitar.

I have been in a position to work on these cheap acoustics and perform "guerilla" repair work with no guarantees. I cannot claim to be the best in the world at my job, but where I work I am, by far, the most qualified to do so.

The quality of the work is, well, I haven't any complaints yet. If I had, my boss would have let me have it.

Sometimes I wish I was at the top of my profession, doing the level and the quality of work that you guys do. But I am a man of many talents, doing electronics work, luthier duties, bass and guitar teacher, lover, fighter, general funky cat, etc. . . Lutherie isn't my primary focus. I do have half a year of training, built a handful of acoustics and even an electric. Built pedals from scratch, worked for a year in a repair shop in the Toronto area doing setups on Squiers and such.

Thank you for your replies.

[pkr2]

Attachment 40105

Attachment 40106

Originally Posted by Gyoon

The instrument is about $200 in value and is from a company that, for a short period of time in 2003, made a batch of instuments using a glue formula that was faulty. (no names) As a result, there are many acoustic guitars with loose braces, lifting bridges and such. I have never seen one of these with the whole fingerboard lifting.

This company is not doing warranty work on these instruments because it is past the one year warranty period. Having seen warranty repairs come back, I am shocked with the incompetency of some of them. Eric, if you suspect that I may not be qualified, then you should check out the work of these guys. It's like they didn't give a rat's behind. It's as if they had 15 minutes to reglue a headstock or reglue the bridge. (actually, this is probably the reality in a warranty service shop)

The condition of the dried glue was fine actually. The fingerboard has an almost "raw wood" quality to the underside and the mating neck surface isn't too bad.

Here's what I think the required, proper way would be to fix it:

Remove fingerboard

Clean the mating surfaces

Glue fingerboard on (a little tricky because the fingerboard is twisting slightly to the drivers side)

Deal with the slight discrepancies in the joint between the fingerboard and neck edge. Touch up the finish to the best of my ablilities

Deal with the frets (i.e. possible fret job, re-hammer loose frets, fret dress)

Whew! Am I missing anything? I guess some of you would have removed the neck to make a respray possible. I'm not equiped for that.

This is over $700 in work, at least. This is 3 and a half times the cost of the guitar.

I have been in a position to work on these cheap acoustics and perform "guerilla" repair work with no guarantees. I cannot claim to be the best in the world at my job, but where I work I am, by far, the most qualified to do so.

The quality of the work is, well, I haven't any complaints yet. If I had, my boss would have let me have it.

Sometimes I wish I was at the top of my profession, doing the level and the quality of work that you guys do. But I am a man of many talents, doing electronics work, luthier duties, bass and guitar teacher, lover, fighter, general funky cat, etc. . . Lutherie isn't my primary focus. I do have half a year of training, built a handful of acoustics and even an electric. Built pedals from scratch, worked for a year in a repair shop in the Toronto area doing setups on Squiers and such.

Thank you for your replies.

Gyoon, I'm certainly not questioning your ability. I've done enough repair work to fully understand time constraints and profit margins. You can't stay in business if you lose money on your time. What you are describing is not a job that should take a huge amount of time of time even if you go the extra yard and R&R the FB.

It sounds as though the glue itself has not broken down so much as it didn't adhere to the FB itself. The mating surfaces that were glued together were, no doudt, two planed surfaces. Without roughing up the surfaces prior to glue up, the stage was set for a possible failed joint. Planed surfaces are too "slick" for the glue to attain full adhesion. Some woods are more prone to weak glue joints than others. Especially ebony or any of the other oily woods commonly used for fingerboards.

There is one common step in using every kind of glue that I know of, including epoxy. That step is the caution to make sure both mating surfaces are clean and dry. If that step is not taken, a joint failure is a distinct possibility. It's not written in stone that the joint will fail, just that it MAY fail.

If you choose to remove the FB completily, you, more than likely can avoid any major fret work if you adjust the truss rod for a straight neck before glue up and clamp the neck to a perfectly flat surface while the glue sets up. I have a thick piece of alminunum channel stock 4" wide that has been run through a jointer to true up the face that I use and it works very nicely.

If you remove one of the position dots at the octave point on the neck before you remove the board, you can just drill a temporary "dowel" hole through the FB and into the neck in the center of the cavity that the dot was removed from. Simply use the butt end of the bit that you drilled the hole with as a temporary dowel to maintain the board in its exact original position. Don't attempt this on a center dot or you may get into the truss rod with the bit.

If you decide to go the full removal route, use a scraper rather than sandpaper to remove the glue. It's real easy to remove wood at the edges of the board with sandpaper and leave a gap between the neck and the FB. Be sure to rough up both sufaces wit some fairly rough grit sandpaper to give the surfaces some "tooth" to adhere to, but avoid the very edges in order to not chip the finish on the neck.

Since the FB is already loose, it shouldn't take very long at all to finish removing it. The fingerboard is not as delicate as you might think as long as the frets are still in the board.

Not counting set up time for the glue, I would estimate it to be no more than a two hour job. The first one that you do will take a bit longer but the experience that you gain will be well worth the time that you spend.You'll be glad when it's finished that you took the time to do it right. The self satisfaction of knowing that the job will hold up is worth far more than the time saved by cutting corners.

The pix are of a job that had some real surprises under the fingerboard. The bass had the same problem as the one you are working on, except that after the fingerboard lifted it was stuck in a closet, still tension on the strings and propped up against the corner with the headstock against the wall. It was in the closet, forgotten, for at least 15 years. The neck looked like a ski ramp.

It came out surprisingly well.

Just thought you may find them of some interest.

Good luck and let us know the outcome.

[Gyoon]

Thank you for all who responded, especially you, pkr62.

It turned out that the customer didn't want to spend the money on it afterall. (the way my situation works is that I quote the store a price and they in turn charge a commission, like 40%! But I digress) This little exchange has taught me a little something about repairwork, about the pride that a lot of you take in your work in doing it right. It's not enough to have skill, "you gotta have heart".

Thanks all. I am coming back here next time I need a reaity check.

Your friend,

Glenn