does my scarf joint need to be repaired?

[88footiee]

not too sure when does it happen but just notice the scarf joint on my neck look like this now
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[mech]

From the way the grain matches and the curve in the crack at the fret marker, I don't think that's a scarf joint. What ever it is, it is separated and does need to be repaired. Looks like string tension pulled the peg head to the treble side.

mech

edit: I would suspect the peg head took a lick or it was caused by truss rod pressure and the wood in that area being really thin at the truss rod channel.

 

[202dy]

It is a scarf joint. It appears to be cut from the same billet. It failed because the joint was "glue starved." It may have been exposed to mechanical shock. It is doubtful that the truss rod had anything to do with it.

Whether it has let go completely or is on it's way it should be diagnosed by a qualified tech. This is not a job for the casual woodworker.

The protocol is to separate the joint enough to clean out the existing glue. Clamping cauls are constructed so that the clamp(s) can exert pressure in the proper direction. Glue is applied and the joint is clamped and cleaned of glue squeeze out. The following day there is a final clean up, touch up if necessary, and a complete set up performed.

 

[JLS]

I've seen way too many of these joints fail.

 

[bassman10096]

I've seen way too many of these joints fail.

It's frustrating when that happens because of poor gluing. But scarf joints are used to prevent more serious damage to the neck or peghead in a fall. A scarf repair is very easy and reliable compared to a random break where the wood may shatter, pieces get lost, edges at bad angles to reglue, etc. Not sure whether they might also be used as a construction convenience in cheaper basses, but virtually all high end instruments have them. I read somewhere that all the surviving Stradivarius violins have had scarf joint repairs - I guess that beats losing the instrument altogether.

 

[mech]

It is a scarf joint. It appears to be cut from the same billet. It failed because the joint was "glue starved." It may have been exposed to mechanical shock. It is doubtful that the truss rod had anything to do with it..

Man, learn something every day. I don't recall noticing a scarf joint that far into the neck but as well as this one could be hidden by using the same stick, there's no wonder. I do see the mismatch in the grain on the side now. Looks like about a 7 degree cut which would have removed about 5/16" of wood at the base of the cut (just eye-balling).

The finger board will need to be un-glued from the peg head portion for a good clean up.

What brand is it?

mech

 

[202dy]

Man, learn something every day. I don't recall noticing a scarf joint that far into the neck but as well as this one could be hidden by using the same stick, there's no wonder. I do see the mismatch in the grain on the side now. Looks like about a 7 degree cut which would have removed about 5/16" of wood at the base of the cut (just eye-balling).

The finger board will need to be un-glued from the peg head portion for a good clean up.

What brand is it?

mech

Open the joint enough to work. Using thin scrapers, clean the joint. A scraper can be made from a thin pallette knife, an old X-acto saw blade or the like by turning a hook on the end. It is important to stay away from the edges of the joint. Any wood that is removed is going to be easy to see and feel. It is also more work to fix another problem.

Another way to do it is to heat the blade till it is good and warm and place it on the mating surface. It will melt the glue and stick to the metal. Pull it, clean it, do it again until both sides of the joint are clean.

Do not use sandpaper for this task!

Once the joint is clean, apply woodworking glue, clamp, clean and do any touch up work that is necessary.

Fingerboard removal is unnecessary. Removal is more of a hindrance than an advantage, and it turns this into a much more expensive job.

This is a job for the seriously handy only. If you hear the word "tool" you think "software", that a vise is a bad habit, or that stuffing toothpicks in a stripped out strap button hole is woodworking, take this to a pro.

 

[mech]

.....A scraper can be made from a thin pallette knife, an old X-acto blade or the like by turning a hook on the end....

Set a burr on the edge?

...Another way to do it is to heat the blade till it is good and warm and place it on the mating surface. It will melt the glue and stick to the metal. Pull it, clean it, do it again until both sides are clean....

Good info. Thanks.

mech

 

[202dy]

Yes. Turn a burr on the edge. Usually multiple times, depending on how much glue is in the joint. The trick is remove the glue and leave the wood as it was originally machined. Not for the faint of heart.

 

[88footiee]

Man, learn something every day. I don't recall noticing a scarf joint that far into the neck but as well as this one could be hidden by using the same stick, there's no wonder. I do see the mismatch in the grain on the side now. Looks like about a 7 degree cut which would have removed about 5/16" of wood at the base of the cut (just eye-balling).

The finger board will need to be un-glued from the peg head portion for a good clean up.

What brand is it?

mech

its a aria pro ii. i only noticed it when i took out for some photos after reading the bass photography thread. quite a bummer